Release notes for Python 3.5.4

What's New in Python 3.5.4 final?

*Release date: 2017-08-07*


- bpo-30119: ftplib.FTP.putline() now throws ValueError on commands that
  contains CR or LF. Patch by Dong-hee Na.

What's New in Python 3.5.4 release candidate 1?

*Release date: 2017-07-23*


- bpo-30730: Prevent environment variables injection in subprocess on
  Windows.  Prevent passing other environment variables and command

- bpo-30694: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of multiple
  security vulnerabilities including: CVE-2017-9233 (External entity
  infinite loop DoS), CVE-2016-9063 (Integer overflow, re-fix),
  CVE-2016-0718 (Fix regression bugs from 2.2.0's fix to CVE-2016-0718) and
  CVE-2012-0876 (Counter hash flooding with SipHash). Note: the
  CVE-2016-5300 (Use os- specific entropy sources like getrandom) doesn't
  impact Python, since Python already gets entropy from the OS to set the
  expat secret using ``XML_SetHashSalt()``.

- bpo-30500: Fix urllib.parse.splithost() to correctly parse fragments. For
  example, ``splithost('//')`` now correctly returns the
  ```` host, instead of treating ```` as the host in an
  authentification (``login@host``).

- bpo-29591: Update expat copy from 2.1.1 to 2.2.0 to get fixes of
  CVE-2016-0718 and CVE-2016-4472. See for more information.

Core and Builtins

- bpo-30876: Relative import from unloaded package now reimports the package
  instead of failing with SystemError.  Relative import from non-package now
  fails with ImportError rather than SystemError.

- bpo-30765: Avoid blocking in pthread_mutex_lock() when
  PyThread_acquire_lock() is asked not to block.

- bpo-27945: Fixed various segfaults with dict when input collections are
  mutated during searching, inserting or comparing.  Based on patches by
  Duane Griffin and Tim Mitchell.

- bpo-25794: Fixed type.__setattr__() and type.__delattr__() for non-
  interned attribute names.  Based on patch by Eryk Sun.

- bpo-29935: Fixed error messages in the index() method of tuple, list and
  deque when pass indices of wrong type.

- bpo-28876: ``bool(range)`` works even if ``len(range)`` raises

- bpo-29600: Fix wrapping coroutine return values in StopIteration.

- bpo-29537: Restore runtime compatibility with bytecode files generated by
  CPython 3.5.0 to 3.5.2, and adjust the eval loop to avoid the problems
  that could be caused by the malformed variant of the
  BUILD_MAP_UNPACK_WITH_CALL opcode that they may contain. Patch by Petr
  Viktorin, Serhiy Storchaka, and Nick Coghlan.

- bpo-28598: Support __rmod__ for subclasses of str being called before
  str.__mod__. Patch by Martijn Pieters.

- bpo-29602: Fix incorrect handling of signed zeros in complex constructor
  for complex subclasses and for inputs having a __complex__ method. Patch
  by Serhiy Storchaka.

- bpo-29347: Fixed possibly dereferencing undefined pointers when creating
  weakref objects.

- bpo-29438: Fixed use-after-free problem in key sharing dict.

- bpo-29319: Prevent RunMainFromImporter overwriting sys.path[0].

- bpo-29337: Fixed possible BytesWarning when compare the code objects.
  Warnings could be emitted at compile time.

- bpo-29478: If max_line_length=None is specified while using the Compat32
  policy, it is no longer ignored.  Patch by Mircea Cosbuc.


- bpo-29403: Fix ``unittest.mock``'s autospec to not fail on method-bound
  builtin functions.  Patch by Aaron Gallagher.

- bpo-30961: Fix decrementing a borrowed reference in tracemalloc.

- bpo-30886: Fix multiprocessing.Queue.join_thread(): it now waits until the
  thread completes, even if the thread was started by the same process which
  created the queue.

- bpo-29854: Fix segfault in readline when using readline's history-size
  option.  Patch by Nir Soffer.

- bpo-30807: signal.setitimer() may disable the timer when passed a tiny

  Tiny values (such as 1e-6) are valid non-zero values for setitimer(),
  which is specified as taking microsecond-resolution intervals. However, on
  some platform, our conversion routine could convert 1e-6 into a zero
  interval, therefore disabling the timer instead of (re-)scheduling it.

- bpo-30441: Fix bug when modifying os.environ while iterating over it

- bpo-30532: Fix email header value parser dropping folding white space in
  certain cases.

- bpo-29169: Update zlib to 1.2.11.

- bpo-30879: os.listdir() and os.scandir() now emit bytes names when called
  with bytes- like argument.

- bpo-30746: Prohibited the '=' character in environment variable names in
  ``os.putenv()`` and ``os.spawn*()``.

- bpo-29755: Fixed the lgettext() family of functions in the gettext module.
  They now always return bytes.

- bpo-30645: Fix path calculation in imp.load_package(), fixing it for cases
  when a package is only shipped with bytecodes. Patch by Alexandru

- bpo-23890: unittest.TestCase.assertRaises() now manually breaks a
  reference cycle to not keep objects alive longer than expected.

- bpo-30149: inspect.signature() now supports callables with variable-
  argument parameters wrapped with partialmethod. Patch by Dong-hee Na.

- bpo-29931: Fixed comparison check for ipaddress.ip_interface objects.
  Patch by Sanjay Sundaresan.

- bpo-24484: Avoid race condition in multiprocessing cleanup.

- bpo-28994: The traceback no longer displayed for SystemExit raised in a
  callback registered by atexit.

- bpo-30508: Don't log exceptions if Task/Future "cancel()" method was

- bpo-28556: Updates to typing module: Add generic AsyncContextManager, add
  support for ContextManager on all versions. Original PRs by Jelle Zijlstra
  and Ivan Levkivskyi

- bpo-29870: Fix ssl sockets leaks when connection is aborted in asyncio/ssl
  implementation. Patch by Michaël Sghaïer.

- bpo-29743: Closing transport during handshake process leaks open socket.
  Patch by Nikolay Kim

- bpo-27585: Fix waiter cancellation in asyncio.Lock. Patch by Mathieu

- bpo-30418: On Windows, subprocess.Popen.communicate() now also ignore
  EINVAL on stdin.write() if the child process is still running but closed
  the pipe.

- bpo-30378: Fix the problem that logging.handlers.SysLogHandler cannot
  handle IPv6 addresses.

- bpo-29960: Preserve generator state when _random.Random.setstate() raises
  an exception. Patch by Bryan Olson.

- bpo-30414: multiprocessing.Queue._feed background running thread do not
  break from main loop on exception.

- bpo-30003: Fix handling escape characters in HZ codec.  Based on patch by
  Ma Lin.

- bpo-30301: Fix AttributeError when using SimpleQueue.empty() under *spawn*
  and *forkserver* start methods.

- bpo-30329: imaplib and poplib now catch the Windows socket WSAEINVAL error
  (code 10022) on shutdown(SHUT_RDWR): An invalid operation was attempted.
  This error occurs sometimes on SSL connections.

- bpo-30375: Warnings emitted when compile a regular expression now always
  point to the line in the user code.  Previously they could point into
  inners of the re module if emitted from inside of groups or conditionals.

- bpo-30048: Fixed ``Task.cancel()`` can be ignored when the task is running
  coroutine and the coroutine returned without any more ``await``.

- bpo-29990: Fix range checking in GB18030 decoder.  Original patch by Ma

- bpo-26293: Change resulted because of zipfile breakage. (See also:

- bpo-30243: Removed the __init__ methods of _json's scanner and encoder.
  Misusing them could cause memory leaks or crashes.  Now scanner and
  encoder objects are completely initialized in the __new__ methods.

- bpo-30185: Avoid KeyboardInterrupt tracebacks in forkserver helper process
  when Ctrl-C is received.

- bpo-28556: Various updates to typing module: add typing.NoReturn type, use
  WrapperDescriptorType, minor bug-fixes.  Original PRs by Jim Fasarakis-
  Hilliard and Ivan Levkivskyi.

- bpo-30205: Fix getsockname() for unbound AF_UNIX sockets on Linux.

- bpo-30070: Fixed leaks and crashes in errors handling in the parser

- bpo-30061: Fixed crashes in IOBase methods __next__() and readlines() when
  readline() or __next__() respectively return non-sizeable object. Fixed
  possible other errors caused by not checking results of PyObject_Size(),
  PySequence_Size(), or PyMapping_Size().

- bpo-30068: _io._IOBase.readlines will check if it's closed first when hint
  is present.

- bpo-29694: Fixed race condition in pathlib mkdir with flags parents=True.
  Patch by Armin Rigo.

- bpo-29692: Fixed arbitrary unchaining of RuntimeError exceptions in
  contextlib.contextmanager.  Patch by Siddharth Velankar.

- bpo-29998: Pickling and copying ImportError now preserves name and path

- bpo-29942: Fix a crash in itertools.chain.from_iterable when encountering
  long runs of empty iterables.

- bpo-27863: Fixed multiple crashes in ElementTree caused by race conditions
  and wrong types.

- bpo-28699: Fixed a bug in pools in multiprocessing.pool that raising an
  exception at the very first of an iterable may swallow the exception or
  make the program hang. Patch by Davin Potts and Xiang Zhang.

- bpo-25803: Avoid incorrect errors raised by Path.mkdir(exist_ok=True) when
  the OS gives priority to errors such as EACCES over EEXIST.

- bpo-29861: Release references to tasks, their arguments and their results
  as soon as they are finished in multiprocessing.Pool.

- bpo-29884: faulthandler: Restore the old sigaltstack during teardown.
  Patch by Christophe Zeitouny.

- bpo-25455: Fixed crashes in repr of recursive buffered file-like objects.

- bpo-29800: Fix crashes in partial.__repr__ if the keys of partial.keywords
  are not strings.  Patch by Michael Seifert.

- bpo-29742: get_extra_info() raises exception if get called on closed ssl
  transport. Patch by Nikolay Kim.

- bpo-8256: Fixed possible failing or crashing input() if attributes
  "encoding" or "errors" of sys.stdin or sys.stdout are not set or are not

- bpo-28298: Fix a bug that prevented array 'Q', 'L' and 'I' from accepting
  big intables (objects that have __int__) as elements.  Patch by Oren

- bpo-29615: SimpleXMLRPCDispatcher no longer chains KeyError (or any other
  exception) to exception(s) raised in the dispatched methods. Patch by Petr

- bpo-29704: asyncio.subprocess.SubprocessStreamProtocol no longer closes
  before all pipes are closed.

- bpo-29703: Fix asyncio to support instantiation of new event loops in
  child processes.

- bpo-29376: Fix assertion error in threading._DummyThread.is_alive().

- bpo-29110: Fix file object leak in when file is given as a
  filesystem path and is not in valid AIFF format. Patch by Anthony Zhang.

- bpo-28961: Fix unittest.mock._Call helper: don't ignore the name parameter
  anymore. Patch written by Jiajun Huang.

- bpo-29532: Altering a kwarg dictionary passed to functools.partial() no
  longer affects a partial object after creation.

- bpo-28556: Various updates to typing module: typing.Counter,
  typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle
  Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

- bpo-29100: Fix datetime.fromtimestamp() regression introduced in Python
  3.6.0: check minimum and maximum years.

- bpo-29519: Fix weakref spewing exceptions during interpreter shutdown when
  used with a rare combination of multiprocessing and custom codecs.

- bpo-29416: Prevent infinite loop in pathlib.Path.mkdir

- bpo-29444: Fixed out-of-bounds buffer access in the group() method of the
  match object. Based on patch by WGH.

- bpo-29335: Fix subprocess.Popen.wait() when the child process has exited
  to a stopped instead of terminated state (ex: when under ptrace).

- bpo-29290: Fix a regression in argparse that help messages would wrap at
  non-breaking spaces.

- bpo-28735: Fixed the comparison of mock.MagickMock with mock.ANY.

- bpo-29011: Fix an important omission by adding Deque to the typing module.

- bpo-29219: Fixed infinite recursion in the repr of uninitialized
  ctypes.CDLL instances.

- bpo-28969: Fixed race condition in C implementation of
  functools.lru_cache. KeyError could be raised when cached function with
  full cache was simultaneously called from differen threads with the same
  uncached arguments.

- bpo-29142: In urllib.request, suffixes in no_proxy environment variable
  with leading dots could match related hostnames again (e.g. .b.c matches
  a.b.c). Patch by Milan Oberkirch.


- bpo-30176: Add missing attribute related constants in curses

- bpo-26985: Add missing info of code object in inspect documentation.

- bpo-28929: Link the documentation to its source file on GitHub.

- bpo-25008: Document as effectively deprecated and add a pointer
  to aiosmtpd, a third-party asyncio-based replacement.

- bpo-26355: Add canonical header link on each page to corresponding major
  version of the documentation. Patch by Matthias Bussonnier.

- bpo-29349: Fix Python 2 syntax in code for building the documentation.


- bpo-30822: Fix regrtest command line parser to allow passing -u
  extralargefile to run test_zipfile64.

- bpo-30383: regrtest: Enhance regrtest and backport features from the
  master branch.

  Add options: --coverage, --testdir, --list-tests (list test files, don't
  run them), --list-cases (list test identifiers, don't run them,
  :issue:`30523`), --matchfile (load a list of test filters from a text
  file, :issue:`30540`), --slowest (alias to --slow).

  Enhance output: add timestamp, test result, currently running tests,
  "Tests result: xxx" summary with total duration, etc.

  Fix reference leak hunting in regrtest, --huntrleaks: regrtest now warms
  up caches, create explicitly all internal singletons which are created on
  demand to prevent false positives when checking for reference leaks.

- bpo-30357: test_thread: setUp() now uses support.threading_setup() and
  support.threading_cleanup() to wait until threads complete to avoid random
  side effects on following tests. Initial patch written by Grzegorz

- bpo-28087: Skip test_asyncore and test_eintr poll failures on macOS. Skip
  some tests of select.poll when running on macOS due to unresolved issues
  with the underlying system poll function on some macOS versions.

- bpo-30197: Enhanced functions swap_attr() and swap_item() in the module. They now work when delete replaced attribute or item
  inside the with statement.  The old value of the attribute or item (or
  None if it doesn't exist) now will be assigned to the target of the "as"
  clause, if there is one.

- bpo-29571: to match the behaviour of the ``re.LOCALE`` flag,
  test_re.test_locale_flag now uses ``locale.getpreferredencoding(False)``
  to determine the candidate encoding for the test regex (allowing it to
  correctly skip the test when the default locale encoding is a multi-byte


- bpo-29243: Prevent unnecessary rebuilding of Python during ``make test``,
  ``make install`` and some other make targets when configured with
  ``--enable- optimizations``.

- bpo-23404: Don't regenerate generated files based on file modification
  time anymore: the action is now explicit. Replace ``make touch`` with
  ``make regen-all``.

- bpo-29643: Fix ``--enable-optimization`` didn't work.


- bpo-30687: Locate msbuild.exe on Windows when building rather than

- bpo-29392: Prevent crash when passing invalid arguments into msvcrt


- bpo-27867: Function PySlice_GetIndicesEx() is replaced with a macro if
  Py_LIMITED_API is set to the value between 0x03050400 and 0x03060000 (not
  including) or 0x03060100 or higher.

- bpo-29083: Fixed the declaration of some public API functions.
  PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in
  limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and
  Py_BuildValue() were not available in limited API of version < 3.3 when
  PY_SSIZE_T_CLEAN is defined.

What's New in Python 3.5.3 final?

*Release date: 2017-01-17*

There were no code changes between 3.5.3rc1 and 3.5.3 final.

What's New in Python 3.5.3 release candidate 1?

*Release date: 2017-01-02*

Core and Builtins

- bpo-29073: bytearray formatting no longer truncates on first null byte.

- bpo-28932: Do not include  if it does not exist.

- bpo-28147: Fix a memory leak in split-table dictionaries: setattr() must
  not convert combined table into split table.

- bpo-25677: Correct the positioning of the syntax error caret for indented
  blocks. Based on patch by Michael Layzell.

- bpo-29000: Fixed bytes formatting of octals with zero padding in alternate

- bpo-28512: Fixed setting the offset attribute of SyntaxError by
  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

- bpo-28991: functools.lru_cache() was susceptible to an obscure reentrancy
  bug caused by a monkey-patched len() function.

- bpo-28648: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X
  when decode astral characters.  Patch by Xiang Zhang.

- bpo-19398: Extra slash no longer added to sys.path components in case of
  empty compile- time PYTHONPATH components.

- bpo-28426: Fixed potential crash in PyUnicode_AsDecodedObject() in debug

- bpo-23782: Fixed possible memory leak in _PyTraceback_Add() and exception
  loss in PyTraceBack_Here().

- bpo-28379: Added sanity checks and tests for PyUnicode_CopyCharacters().
  Patch by Xiang Zhang.

- bpo-28376: The type of long range iterator is now registered as Iterator.
  Patch by Oren Milman.

- bpo-28376: The constructor of range_iterator now checks that step is not
  0. Patch by Oren Milman.

- bpo-26906: Resolving special methods of uninitialized type now causes
  implicit initialization of the type instead of a fail.

- bpo-18287: PyType_Ready() now checks that tp_name is not NULL. Original
  patch by Niklas Koep.

- bpo-24098: Fixed possible crash when AST is changed in process of
  compiling it.

- bpo-28350: String constants with null character no longer interned.

- bpo-26617: Fix crash when GC runs during weakref callbacks.

- bpo-27942: String constants now interned recursively in tuples and

- bpo-21578: Fixed misleading error message when ImportError called with
  invalid keyword args.

- bpo-28203: Fix incorrect type in error message from ``complex(1.0,
  {2:3})``. Patch by Soumya Sharma.

- bpo-27955: Fallback on reading /dev/urandom device when the getrandom()
  syscall fails with EPERM, for example when blocked by SECCOMP.

- bpo-28131: Fix a regression in zipimport's compile_source().  zipimport
  should use the same optimization level as the interpreter.

- bpo-25221: Fix corrupted result from PyLong_FromLong(0) when Python is
  compiled with NSMALLPOSINTS = 0.

- bpo-25758: Prevents zipimport from unnecessarily encoding a filename
  (patch by Eryk Sun)

- bpo-28189: dictitems_contains no longer swallows compare errors. (Patch by
  Xiang Zhang)

- bpo-27812: Properly clear out a generator's frame's backreference to the
  generator to prevent crashes in frame.clear().

- bpo-27811: Fix a crash when a coroutine that has not been awaited is
  finalized with warnings-as-errors enabled.

- bpo-27587: Fix another issue found by PVS-Studio: Null pointer check after
  use of 'def' in _PyState_AddModule(). Initial patch by Christian Heimes.

- bpo-26020: set literal evaluation order did not match documented

- bpo-27782: Multi-phase extension module import now correctly allows the
  ``m_methods`` field to be used to add module level functions to instances
  of non-module types returned from ``Py_create_mod``. Patch by Xiang Zhang.

- bpo-27936: The round() function accepted a second None argument for some
  types but not for others.  Fixed the inconsistency by accepting None for
  all numeric types.

- bpo-27487: Warn if a submodule argument to "python -m" or
  runpy.run_module() is found in sys.modules after parent packages are
  imported, but before the submodule is executed.

- bpo-27558: Fix a SystemError in the implementation of "raise" statement.
  In a brand new thread, raise a RuntimeError since there is no active
  exception to reraise. Patch written by Xiang Zhang.

- bpo-27419: Standard __import__() no longer look up "__import__" in globals
  or builtins for importing submodules or "from import".  Fixed handling an
  error of non- string package name.

- bpo-27083: Respect the PYTHONCASEOK environment variable under Windows.

- bpo-27514: Make having too many statically nested blocks a SyntaxError
  instead of SystemError.

- bpo-27473: Fixed possible integer overflow in bytes and bytearray
  concatenations. Patch by Xiang Zhang.

- bpo-27507: Add integer overflow check in bytearray.extend().  Patch by
  Xiang Zhang.

- bpo-27581: Don't rely on wrapping for overflow check in
  PySequence_Tuple().  Patch by Xiang Zhang.

- bpo-27443: __length_hint__() of bytearray iterators no longer return a
  negative integer for a resized bytearray.

- bpo-27942: Fix memory leak in codeobject.c


- bpo-15812: inspect.getframeinfo() now correctly shows the first line of a
  context. Patch by Sam Breese.

- bpo-29094: Offsets in a ZIP file created with extern file object and modes
  "w" and "x" now are relative to the start of the file.

- bpo-13051: Fixed recursion errors in large or resized
  curses.textpad.Textbox.  Based on patch by Tycho Andersen.

- bpo-29119: Fix weakrefs in the pure python version of
  collections.OrderedDict move_to_end() method. Contributed by Andra

- bpo-9770: curses.ascii predicates now work correctly with negative

- bpo-28427: old keys should not remove new values from WeakValueDictionary
  when collecting from another thread.

- bpo-28923: Remove editor artifacts from

- bpo-28871: Fixed a crash when deallocate deep ElementTree.

- bpo-19542: Fix bugs in WeakValueDictionary.setdefault() and
  WeakValueDictionary.pop() when a GC collection happens in another thread.

- bpo-20191: Fixed a crash in resource.prlimit() when pass a sequence that
  doesn't own its elements as limits.

- bpo-28779: multiprocessing.set_forkserver_preload() would crash the
  forkserver process if a preloaded module instantiated some multiprocessing
  objects such as locks.

- bpo-28847: dbm.dumb now supports reading read-only files and no longer
  writes the index file when it is not changed.

- bpo-25659: In ctypes, prevent a crash calling the from_buffer() and
  from_buffer_copy() methods on abstract classes like Array.

- bpo-28732: Fix crash in os.spawnv() with no elements in args

- bpo-28485: Always raise ValueError for negative
  compileall.compile_dir(workers=...) parameter, even when multithreading is

- bpo-28387: Fixed possible crash in _io.TextIOWrapper deallocator when the
  garbage collector is invoked in other thread.  Based on patch by Sebastian

- bpo-27517: LZMA compressor and decompressor no longer raise exceptions if
  given empty data twice.  Patch by Benjamin Fogle.

- bpo-28549: Fixed segfault in curses's addch() with ncurses6.

- bpo-28449: with mode "r" or "r:" now tries to open a tar
  file with compression before trying to open it without compression.
  Otherwise it had 50% chance failed with ignore_zeros=True.

- bpo-23262: The webbrowser module now supports Firefox 36+ and derived
  browsers.  Based on patch by Oleg Broytman.

- bpo-27939: Fixed bugs in tkinter.ttk.LabeledScale and tkinter.Scale caused
  by representing the scale as float value internally in Tk.  tkinter.IntVar
  now works if float value is set to underlying Tk variable.

- bpo-28255: calendar.TextCalendar().prmonth() no longer prints a space at
  the start of new line after printing a month's calendar.  Patch by Xiang

- bpo-20491: The textwrap.TextWrapper class now honors non-breaking spaces.
  Based on patch by Kaarle Ritvanen.

- bpo-28353: os.fwalk() no longer fails on broken links.

- bpo-25464: Fixed HList.header_exists() in tkinter.tix module by addin a
  workaround to Tix library bug.

- bpo-28488: shutil.make_archive() no longer add entry "./" to ZIP archive.

- bpo-24452: Make webbrowser support Chrome on Mac OS X.

- bpo-20766: Fix references leaked by pdb in the handling of SIGINT

- bpo-26293: Fixed writing ZIP files that starts not from the start of the
  file.  Offsets in ZIP file now are relative to the start of the archive in
  conforming to the specification.

- bpo-28321: Fixed writing non-BMP characters with binary format in

- bpo-28322: Fixed possible crashes when unpickle itertools objects from
  incorrect pickle data.  Based on patch by John Leitch.

- Fix possible integer overflows and crashes in the mmap module with unusual
  usage patterns.

- bpo-1703178: Fix the ability to pass the --link-objects option to the
  distutils build_ext command.

- bpo-28253: Fixed calendar functions for extreme months: 0001-01 and

  Methods itermonthdays() and itermonthdays2() are reimplemented so that
  they don't call itermonthdates() which can cause

- bpo-28275: Fixed possible use after free in the decompress() methods of
  the LZMADecompressor and BZ2Decompressor classes. Original patch by John

- bpo-27897: Fixed possible crash in sqlite3.Connection.create_collation()
  if pass invalid string-like object as a name.  Patch by Xiang Zhang.

- bpo-18893: Fix invalid exception handling in Lib/ctypes/macholib/
  Patch by Madison May.

- bpo-27611: Fixed support of default root window in the tkinter.tix module.

- bpo-27348: In the traceback module, restore the formatting of exception
  messages like "Exception: None".  This fixes a regression introduced in

- bpo-25651: Allow falsy values to be used for msg parameter of subTest().

- bpo-27932: Prevent memory leak in win32_ver().

- Fix UnboundLocalError in socket._sendfile_use_sendfile.

- bpo-28075: Check for ERROR_ACCESS_DENIED in Windows implementation of
  os.stat().  Patch by Eryk Sun.

- bpo-25270: Prevent codecs.escape_encode() from raising SystemError when an
  empty bytestring is passed.

- bpo-28181: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

- bpo-25895: Enable WebSocket URL schemes in urllib.parse.urljoin. Patch by
  Gergely Imreh and Markus Holtermann.

- bpo-27599: Fixed buffer overrun in binascii.b2a_qp() and

- bpo-19003: m email.generator now replaces only ``\r`` and/or ``\n`` line
  endings, per the RFC, instead of all unicode line endings.

- bpo-28019: itertools.count() no longer rounds non-integer step in range
  between 1.0 and 2.0 to 1.

- bpo-25969: Update the lib2to3 grammar to handle the unpacking
  generalizations added in 3.5.

- bpo-14977: mailcap now respects the order of the lines in the mailcap
  files ("first match"), as required by RFC 1542.  Patch by Michael Lazar.

- bpo-24594: Validates persist parameter when opening MSI database

- bpo-17582: xml.etree.ElementTree nows preserves whitespaces in attributes
  (Patch by Duane Griffin.  Reviewed and approved by Stefan Behnel.)

- bpo-28047: Fixed calculation of line length used for the base64 CTE in the
  new email policies.

- bpo-27445: Don't pass str(_charset) to MIMEText.set_payload(). Patch by
  Claude Paroz.

- bpo-22450: urllib now includes an ``Accept: */*`` header among the default
  headers. This makes the results of REST API requests more consistent and
  predictable especially when proxy servers are involved.

- lib2to3.pgen3.driver.load_grammar() now creates a stable cache file
  between runs given the same Grammar.txt input regardless of the hash
  randomization setting.

- bpo-27570: Avoid zero-length memcpy() etc calls with null source pointers
  in the "ctypes" and "array" modules.

- bpo-22233: Break email header lines *only* on the RFC specified CR and LF
  characters, not on arbitrary unicode line breaks.  This also fixes a bug
  in HTTP header parsing.

- bpo-27988: Fix email iter_attachments incorrect mutation of payload list.

- bpo-27691: Fix ssl module's parsing of GEN_RID subject alternative name
  fields in X.509 certs.

- bpo-27850: Remove 3DES from ssl module's default cipher list to counter
  measure sweet32 attack (CVE-2016-2183).

- bpo-27766: Add ChaCha20 Poly1305 to ssl module's default ciper list.
  (Required OpenSSL 1.1.0 or LibreSSL).

- bpo-26470: Port ssl and hashlib module to OpenSSL 1.1.0.

- Remove support for passing a file descriptor to os.access. It never worked
  but previously didn't raise.

- bpo-12885: Fix error when distutils encounters symlink.

- bpo-27881: Fixed possible bugs when setting
  sqlite3.Connection.isolation_level. Based on patch by Xiang Zhang.

- bpo-27861: Fixed a crash in sqlite3.Connection.cursor() when a factory
  creates not a cursor.  Patch by Xiang Zhang.

- bpo-19884: Avoid spurious output on OS X with Gnu Readline.

- bpo-27706: Restore deterministic behavior of random.Random().seed() for
  string seeds using seeding version 1.  Allows sequences of calls to
  random() to exactly match those obtained in Python 2. Patch by Nofar

- bpo-10513: Fix a regression in Connection.commit().  Statements should not
  be reset after a commit.

- A new version of from -
  Collection (only for 3.6) (Issue #27598) - Add FrozenSet to __all__
  (upstream #261) - fix crash in _get_type_vars() (upstream #259) - Remove
  the dict constraint in ForwardRef._eval_type (upstream #252)

- bpo-27539: Fix unnormalised ``Fraction.__pow__`` result in the case of
  negative exponent and negative base.

- bpo-21718: cursor.description is now available for queries using CTEs.

- bpo-2466: posixpath.ismount now correctly recognizes mount points which
  the user does not have permission to access.

- bpo-27773: Correct some memory management errors server_hostname in

- bpo-26750: unittest.mock.create_autospec() now works properly for
  subclasses of property() and other data descriptors.

- In the curses module, raise an error if window.getstr() or window.instr()
  is passed a negative value.

- bpo-27783: Fix possible usage of uninitialized memory in

- bpo-27774: Fix possible Py_DECREF on unowned object in _sre.

- bpo-27760: Fix possible integer overflow in binascii.b2a_qp.

- bpo-27758: Fix possible integer overflow in the _csv module for large
  record lengths.

- bpo-27568: Prevent HTTPoxy attack (CVE-2016-1000110). Ignore the
  HTTP_PROXY variable when REQUEST_METHOD environment is set, which
  indicates that the script is in CGI mode.

- bpo-27656: Do not assume sched.h defines any SCHED_* constants.

- bpo-27130: In the "zlib" module, fix handling of large buffers (typically
  4 GiB) when compressing and decompressing.  Previously, inputs were
  limited to 4 GiB, and compression and decompression operations did not
  properly handle results of 4 GiB.

- bpo-27533: Release GIL in nt._isdir

- bpo-17711: Fixed unpickling by the persistent ID with protocol 0. Original
  patch by Alexandre Vassalotti.

- bpo-27522: Avoid an unintentional reference cycle in email.feedparser.

- bpo-26844: Fix error message for imp.find_module() to refer to 'path'
  instead of 'name'. Patch by Lev Maximov.

- bpo-23804: Fix SSL zero-length recv() calls to not block and not raise an
  error about unclean EOF.

- bpo-27466: Change time format returned by http.cookie.time2netscape,
  confirming the netscape cookie format and making it consistent with

- bpo-26664: Fix by removing mis-use of ``$``.

- bpo-22115: Fixed tracing Tkinter variables: trace_vdelete() with wrong
  mode no longer break tracing, trace_vinfo() now always returns a list of
  pairs of strings, tracing in the "u" mode now works.

- Fix a scoping issue in importlib.util.LazyLoader which triggered an
  UnboundLocalError when lazy-loading a module that was already put into

- bpo-27079: Fixed curses.ascii functions isblank(), iscntrl() and

- bpo-26754: Some functions (compile() etc) accepted a filename argument
  encoded as an iterable of integers. Now only strings and byte-like objects
  are accepted.

- bpo-27048: Prevents distutils failing on Windows when environment
  variables contain non-ASCII characters

- bpo-27330: Fixed possible leaks in the ctypes module.

- bpo-27238: Got rid of bare excepts in the turtle module.  Original patch
  by Jelle Zijlstra.

- bpo-27122: When an exception is raised within the context being managed by
  a contextlib.ExitStack() and one of the exit stack generators catches and
  raises it in a chain, do not re-raise the original exception when exiting,
  let the new chained one through.  This avoids the PEP 479 bug described in


- bpo-27278: Fix os.urandom() implementation using getrandom() on Linux.
  Truncate size to INT_MAX and loop until we collected enough random bytes,
  instead of casting a directly Py_ssize_t to int.


- bpo-26386: Fixed ttk.TreeView selection operations with item id's
  containing spaces.


- bpo-22636: Avoid shell injection problems with ctypes.util.find_library().


- bpo-16182: Fix various functions in the "readline" module to use the
  locale encoding, and fix get_begidx() and get_endidx() to return code
  point indexes.

- bpo-27392: Add loop.connect_accepted_socket(). Patch by Jim Fulton.

- bpo-27930: Improved behaviour of logging.handlers.QueueListener. Thanks to
  Paulo Andrade and Petr Viktorin for the analysis and patch.

- bpo-21201: Improves readability of multiprocessing error message.  Thanks
  to Wojciech Walczak for patch.

- bpo-27456: asyncio: Set TCP_NODELAY by default.

- bpo-27906: Fix socket accept exhaustion during high TCP traffic. Patch by
  Kevin Conway.

- bpo-28174: Handle when SO_REUSEPORT isn't properly supported. Patch by
  Seth Michael Larson.

- bpo-26654: Inspect functools.partial in asyncio.Handle.__repr__. Patch by

- bpo-26909: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

- bpo-28176: Fix callbacks race in asyncio.SelectorLoop.sock_connect.

- bpo-27759: Fix selectors incorrectly retain invalid file descriptors.
  Patch by Mark Williams.

- bpo-28368: Refuse monitoring processes if the child watcher has no loop
  attached. Patch by Vincent Michel.

- bpo-28369: Raise RuntimeError when transport's FD is used with add_reader,
  add_writer, etc.

- bpo-28370: Speedup asyncio.StreamReader.readexactly. Patch by Коренберг

- bpo-28371: Deprecate passing asyncio.Handles to run_in_executor.

- bpo-28372: Fix asyncio to support formatting of non-python coroutines.

- bpo-28399: Remove UNIX socket from FS before binding. Patch by Коренберг

- bpo-27972: Prohibit Tasks to await on themselves.

- bpo-26923: Fix asyncio.Gather to refuse being cancelled once all children
  are done. Patch by Johannes Ebke.

- bpo-26796: Don't configure the number of workers for default threadpool
  executor. Initial patch by Hans Lawrenz.

- bpo-28600: Optimize loop.call_soon().

- bpo-28613: Fix get_event_loop() return the current loop if called from

- bpo-28639: Fix inspect.isawaitable to always return bool Patch by Justin

- bpo-28652: Make loop methods reject socket kinds they do not support.

- bpo-28653: Fix a refleak in functools.lru_cache.

- bpo-28703: Fix asyncio.iscoroutinefunction to handle Mock objects.

- bpo-24142: Reading a corrupt config file left the parser in an invalid
  state.  Original patch by Florian Höch.

- bpo-28990: Fix SSL hanging if connection is closed before handshake
  completed. (Patch by HoHo-Ho)


- bpo-15308: Add 'interrupt execution' (^C) to Shell menu. Patch by Roger
  Serwy, updated by Bayard Randel.

- bpo-27922: Stop IDLE tests from 'flashing' gui widgets on the screen.

- Add version to title of IDLE help window.

- bpo-25564: In section on IDLE -- console differences, mention that using
  exec means that __builtins__ is defined for each statement.

- bpo-27714: text_textview and test_autocomplete now pass when re-run in the
  same process.  This occurs when test_idle fails when run with the -w
  option but without -jn.  Fix warning from test_config.

- bpo-25507: IDLE no longer runs buggy code because of its tkinter imports.
  Users must include the same imports required to run directly in Python.

- bpo-27452: add line counter and crc to IDLE configHandler test dump.

- bpo-27365: Allow non-ascii chars in IDLE NEWS.txt, for contributor names.

- bpo-27245: IDLE: Cleanly delete custom themes and key bindings.
  Previously, when IDLE was started from a console or by import, a cascade
  of warnings was emitted. Patch by Serhiy Storchaka.


- bpo-28808: PyUnicode_CompareWithASCIIString() now never raises exceptions.

- bpo-26754: PyUnicode_FSDecoder() accepted a filename argument encoded as
  an iterable of integers. Now only strings and bytes-like objects are


- bpo-28513: Documented command-line interface of zipfile.


- bpo-28950: Disallow -j0 to be combined with -T/-l/-M in regrtest command
  line arguments.

- bpo-28666: Now is able to remove unwritable or
  unreadable directories.

- bpo-23839: Various caches now are cleared before running every test file.

- bpo-28409: regrtest: fix the parser of command line arguments.

- bpo-27787: Call gc.collect() before checking each test for "dangling
  threads", since the dangling threads are weak references.

- bpo-27369: In test_pyexpat, avoid testing an error message detail that
  changed in Expat 2.2.0.


- bpo-27952: Get Tools/scripts/ working with Python 3 and the
  current "re" module, avoid invalid Python backslash escapes, and fix a bug
  parsing escaped C quote signs.

- bpo-27332: Fixed the type of the first argument of module-level functions
  generated by Argument Clinic.  Patch by Petr Viktorin.

- bpo-27418: Fixed Tools/importbench/


- bpo-28251: Improvements to help manuals on Windows.

- bpo-28110: launcher.msi has different product codes between 32-bit and

- bpo-25144: Ensures TargetDir is set before continuing with custom install.

- bpo-27469: Adds a shell extension to the launcher so that drag and drop
  works correctly.

- bpo-27309: Enabled proper Windows styles in python[w].exe manifest.


- bpo-29080: Removes hard dependency on hg.exe from PCBuild/build.bat

- bpo-23903: Added missed names to PC/python3.def.

- bpo-10656: Fix out-of-tree building on AIX.  Patch by Tristan Carel and
  Michael Haubenwallner.

- bpo-26359: Rename --with-optimiations to --enable-optimizations.

- bpo-28444: Fix missing extensions modules when cross compiling.

- bpo-28248: Update Windows build and OS X installers to use OpenSSL 1.0.2j.

- bpo-28258: Fixed build with Estonian locale (python-config and distclean
  targets in Makefile).  Patch by Arfrever Frehtes Taifersar Arahesis.

- bpo-26661: now detects system libffi with multiarch wrapper.

- bpo-28066: Fix the logic that searches build directories for generated
  include files when building outside the source tree.

- bpo-15819: Remove redundant include search directory option for building
  outside the source tree.

- bpo-27566: Fix clean target in freeze makefile (patch by Lisa Roach)

- bpo-27705: Update message in

- bpo-27983: Cause lack of llvm-profdata tool when using clang as required
  for PGO linking to be a configure time error rather than make time when
  --with- optimizations is enabled.  Also improve our ability to find the
  llvm- profdata tool on MacOS and some Linuxes.

- bpo-26307: The profile-opt build now applies PGO to the built-in modules.

- bpo-26359: Add the --with-optimizations configure flag.

- bpo-27713: Suppress spurious build warnings when updating importlib's
  bootstrap files. Patch by Xiang Zhang

- bpo-25825: Correct the references to Modules/python.exp and ld_so_aix,
  which are required on AIX.  This updates references to an installation
  path that was changed in 3.2a4, and undoes changed references to the build
  tree that were made in 3.5.0a1.

- bpo-27453: CPP invocation in configure must use CPPFLAGS. Patch by Chi
  Hsuan Yen.

- bpo-27641: The configure script now inserts comments into the makefile to
  prevent the pgen and _freeze_importlib executables from being cross-

- bpo-26662: Set PYTHON_FOR_GEN in configure as the Python program to be
  used for file generation during the build.

- bpo-10910: Avoid C++ compilation errors on FreeBSD and OS X. Also update
  FreedBSD version checks for the original ctype UTF-8 workaround.

- bpo-28676: Prevent missing 'getentropy' declaration warning on macOS.
  Patch by Gareth Rees.

What's New in Python 3.5.2 final?

*Release date: 2016-06-26*

Core and Builtins

- bpo-26930: Update Windows builds to use OpenSSL 1.0.2h.


- bpo-26867: Ubuntu's openssl OP_NO_SSLv3 is forced on by default; fix test.


- bpo-27365: Allow non-ascii in idlelib/NEWS.txt - minimal part for 3.5.2.

What's New in Python 3.5.2 release candidate 1?

*Release date: 2016-06-12*

Core and Builtins

- bpo-27066: Fixed SystemError if a custom opener (for open()) returns a
  negative number without setting an exception.

- bpo-20041: Fixed TypeError when frame.f_trace is set to None. Patch by
  Xavier de Gaye.

- bpo-26168: Fixed possible refleaks in failing Py_BuildValue() with the "N"
  format unit.

- bpo-26991: Fix possible refleak when creating a function with annotations.

- bpo-27039: Fixed bytearray.remove() for values greater than 127.  Patch by
  Joe Jevnik.

- bpo-23640: int.from_bytes() no longer bypasses constructors for

- bpo-26811: gc.get_objects() no longer contains a broken tuple with NULL

- bpo-20120: Use RawConfigParser for .pypirc parsing, removing support for
  interpolation unintentionally added with move to Python 3. Behavior no
  longer does any interpolation in .pypirc files, matching behavior in
  Python 2.7 and Setuptools 19.0.

- bpo-26659: Make the builtin slice type support cycle collection.

- bpo-26718: super.__init__ no longer leaks memory if called multiple times.
  NOTE: A direct call of super.__init__ is not endorsed!

- bpo-25339: PYTHONIOENCODING now has priority over locale in setting the
  error handler for stdin and stdout.

- bpo-26494: Fixed crash on iterating exhausting iterators. Affected classes
  are generic sequence iterators, iterators of str, bytes, bytearray, list,
  tuple, set, frozenset, dict, OrderedDict, corresponding views and
  os.scandir() iterator.

- bpo-26581: If coding cookie is specified multiple times on a line in
  Python source code file, only the first one is taken to account.

- bpo-26464: Fix str.translate() when string is ASCII and first replacements
  removes character, but next replacement uses a non-ASCII character or a
  string longer than 1 character. Regression introduced in Python 3.5.0.

- bpo-22836: Ensure exception reports from PyErr_Display() and
  PyErr_WriteUnraisable() are sensible even when formatting them produces
  secondary errors.  This affects the reports produced by
  sys.__excepthook__() and when __del__() raises an exception.

- bpo-26302: Correct behavior to reject comma as a legal character for
  cookie names.

- bpo-4806: Avoid masking the original TypeError exception when using star
  (``*``) unpacking in function calls.  Based on patch by Hagen Fürstenau
  and Daniel Urban.

- bpo-27138: Fix the doc comment for FileFinder.find_spec().

- bpo-26154: Add a new private _PyThreadState_UncheckedGet() function to get
  the current Python thread state, but don't issue a fatal error if it is
  NULL. This new function must be used instead of accessing directly the
  _PyThreadState_Current variable.  The variable is no more exposed since
  Python 3.5.1 to hide the exact implementation of atomic C types, to avoid
  compiler issues.

- bpo-26194: Deque.insert() gave odd results for bounded deques that had
  reached their maximum size.  Now an IndexError will be raised when
  attempting to insert into a full deque.

- bpo-25843: When compiling code, don't merge constants if they are equal
  but have a different types. For example, ``f1, f2 = lambda: 1, lambda:
  1.0`` is now correctly compiled to two different functions: ``f1()``
  returns ``1`` (``int``) and ``f2()`` returns ``1.0`` (``int``), even if
  ``1`` and ``1.0`` are equal.

- bpo-22995: [UPDATE] Comment out the one of the pickleability tests in
  _PyObject_GetState() due to regressions observed in Cython-based projects.

- bpo-25961: Disallowed null characters in the type name.

- bpo-25973: Fix segfault when an invalid nonlocal statement binds a name
  starting with two underscores.

- bpo-22995: Instances of extension types with a state that aren't
  subclasses of list or dict and haven't implemented any pickle-related
  methods (__reduce__, __reduce_ex__, __getnewargs__, __getnewargs_ex__, or
  __getstate__), can no longer be pickled.  Including memoryview.

- bpo-20440: Massive replacing unsafe attribute setting code with special
  macro Py_SETREF.

- bpo-25766: Special method __bytes__() now works in str subclasses.

- bpo-25421: __sizeof__ methods of builtin types now use dynamic basic size.
  This allows sys.getsize() to work correctly with their subclasses with
  __slots__ defined.

- bpo-25709: Fixed problem with in-place string concatenation and utf-8

- bpo-27147: Mention PEP 420 in the importlib docs.

- bpo-24097: Fixed crash in object.__reduce__() if slot name is freed inside

- bpo-24731: Fixed crash on converting objects with special methods
  __bytes__, __trunc__, and __float__ returning instances of subclasses of
  bytes, int, and float to subclasses of bytes, int, and float

- bpo-26478: Fix semantic bugs when using binary operators with dictionary
  views and tuples.

- bpo-26171: Fix possible integer overflow and heap corruption in

- bpo-25660: Fix TAB key behaviour in REPL with readline.

- bpo-25887: Raise a RuntimeError when a coroutine object is awaited more
  than once.

- bpo-27243: Update the __aiter__ protocol: instead of returning an
  awaitable that resolves to an asynchronous iterator, the asynchronous
  iterator should be returned directly.  Doing the former will trigger a


- bpo-26556: Update expat to 2.1.1, fixes CVE-2015-1283.

- Fix TLS stripping vulnerability in smtplib, CVE-2016-0772. Reported by
  Team Oststrom


- bpo-21386: Implement missing IPv4Address.is_global property.  It was
  documented since 07a5610bae9d.  Initial patch by Roger Luethi.

- bpo-20900: distutils register command now decodes HTTP responses
  correctly.  Initial patch by ingrid.

- A new version of provides several new classes and features:
  @overload outside stubs, Reversible, DefaultDict, Text, ContextManager,
  Type[], NewType(), TYPE_CHECKING, and numerous bug fixes (note that some
  of the new features are not yet implemented in mypy or other static
  analyzers). Also classes for PEP 492 (Awaitable, AsyncIterable,
  AsyncIterator) have been added (in fact they made it into 3.5.1 but were
  never mentioned).

- bpo-25738: Stop http.server.BaseHTTPRequestHandler.send_error() from
  sending a message body for 205 Reset Content.  Also, don't send Content
  header fields in responses that don't have a body.  Patch by Susumu

- bpo-21313: Fix the "platform" module to tolerate when sys.version contains
  truncated build information.


- bpo-26839: On Linux, :func:`os.urandom` now calls ``getrandom()`` with
  ``GRND_NONBLOCK`` to fall back on reading ``/dev/urandom`` if the urandom
  entropy pool is not initialized yet. Patch written by Colm Buckley.


- bpo-27164: In the zlib module, allow decompressing raw Deflate streams
  with a predefined zdict.  Based on patch by Xiang Zhang.

- bpo-24291: Fix wsgiref.simple_server.WSGIRequestHandler to completely
  write data to the client.  Previously it could do partial writes and
  truncate data.  Also, wsgiref.handler.ServerHandler can now handle stdout
  doing partial writes, but this is deprecated.

- bpo-26809: Add ``__all__`` to :mod:`string`.  Patch by Emanuel Barry.

- bpo-26373: subprocess.Popen.communicate now correctly ignores
  BrokenPipeError when the child process dies before .communicate() is
  called in more/all circumstances.

- bpo-21776: distutils.upload now correctly handles HTTPError. Initial patch
  by Claudiu Popa.

- bpo-27114: Fix SSLContext._load_windows_store_certs fails with

- bpo-18383: Avoid creating duplicate filters when using filterwarnings and
  simplefilter. Based on patch by Alex Shkop.

- bpo-27057: Fix os.set_inheritable() on Android, ioctl() is blocked by
  SELinux and fails with EACCESS. The function now falls back to fcntl().
  Patch written by Michał Bednarski.

- bpo-27014: Fix infinite recursion using  Thanks to Kalle Tuure!

- bpo-14132: Fix urllib.request redirect handling when the target only has a
  query string.  Original fix by Ján Janech.

- bpo-17214: The "urllib.request" module now percent-encodes non-ASCII bytes
  found in redirect target URLs.  Some servers send Location header fields
  with non- ASCII bytes, but "http.client" requires the request target to be
  ASCII- encodable, otherwise a UnicodeEncodeError is raised.  Based on
  patch by Christian Heimes.

- bpo-26892: Honor debuglevel flag in urllib.request.HTTPHandler. Patch
  contributed by Chi Hsuan Yen.

- bpo-22274: In the subprocess module, allow stderr to be redirected to
  stdout even when stdout is not redirected.  Patch by Akira Li.

- bpo-26807: mock_open 'files' no longer error on readline at end of file.
  Patch from Yolanda Robla.

- bpo-25745: Fixed leaking a userptr in curses panel destructor.

- bpo-26977: Removed unnecessary, and ignored, call to sum of squares helper
  in statistics.pvariance.

- bpo-26881: The modulefinder module now supports extended opcode arguments.

- bpo-23815: Fixed crashes related to directly created instances of types in
  _tkinter and curses.panel modules.

- bpo-17765: weakref.ref() no longer silently ignores keyword arguments.
  Patch by Georg Brandl.

- bpo-26873: xmlrpc now raises ResponseError on unsupported type tags
  instead of silently return incorrect result.

- bpo-26711: Fixed the comparison of plistlib.Data with other types.

- bpo-24114: Fix an uninitialized variable in `ctypes.util`.

  The bug only occurs on SunOS when the ctypes implementation searches for
  the `crle` program.  Patch by Xiang Zhang.  Tested on SunOS by Kees Bos.

- bpo-26864: In urllib.request, change the proxy bypass host checking
  against no_proxy to be case-insensitive, and to not match unrelated host
  names that happen to have a bypassed hostname as a suffix.  Patch by Xiang

- bpo-26634: recursive_repr() now sets __qualname__ of wrapper.  Patch by
  Xiang Zhang.

- bpo-26804: urllib.request will prefer lower_case proxy environment
  variables over UPPER_CASE or Mixed_Case ones. Patch contributed by Hans-
  Peter Jansen.

- bpo-26837: assertSequenceEqual() now correctly outputs non-stringified
  differing items (like bytes in the -b mode).  This affects
  assertListEqual() and assertTupleEqual().

- bpo-26041: Remove "will be removed in Python 3.7" from deprecation
  messages of platform.dist() and platform.linux_distribution(). Patch by
  Kumaripaba Miyurusara Athukorala.

- bpo-26822: itemgetter, attrgetter and methodcaller objects no longer
  silently ignore keyword arguments.

- bpo-26733: Disassembling a class now disassembles class and static
  methods. Patch by Xiang Zhang.

- bpo-26801: Fix error handling in :func:`shutil.get_terminal_size`, catch
  :exc:`AttributeError` instead of :exc:`NameError`. Patch written by
  Emanuel Barry.

- bpo-24838: tarfile's ustar and gnu formats now correctly calculate name
  and link field limits for multibyte character encodings like utf-8.


- bpo-26657: Fix directory traversal vulnerability with http.server on
  Windows.  This fixes a regression that was introduced in 3.3.4rc1 and
  3.4.0rc1.  Based on patch by Philipp Hagemeister.


- bpo-26717: Stop encoding Latin-1-ized WSGI paths with UTF-8.  Patch by
  Anthony Sottile.

- bpo-26735: Fix :func:`os.urandom` on Solaris 11.3 and newer when reading
  more than 1,024 bytes: call ``getrandom()`` multiple times with a limit of
  1024 bytes per call.

- bpo-16329: Add .webm to mimetypes.types_map.  Patch by Giampaolo Rodola'.

- bpo-13952: Add .csv to mimetypes.types_map.  Patch by Geoff Wilson.

- bpo-26709: Fixed Y2038 problem in loading binary PLists.

- bpo-23735: Handle terminal resizing with Readline 6.3+ by installing our
  own SIGWINCH handler.  Patch by Eric Price.

- bpo-26586: In http.server, respond with "413 Request header fields too
  large" if there are too many header fields to parse, rather than killing
  the connection and raising an unhandled exception.  Patch by Xiang Zhang.

- bpo-22854: Change BufferedReader.writable() and BufferedWriter.readable()
  to always return False.

- bpo-25195: Fix a regression in mock.MagicMock. _Call is a subclass of
  tuple (changeset 3603bae63c13 only works for classes) so we need to
  implement __ne__ ourselves.  Patch by Andrew Plummer.

- bpo-26644: Raise ValueError rather than SystemError when a negative length
  is passed to SSLSocket.recv() or read().

- bpo-23804: Fix SSL recv(0) and read(0) methods to return zero bytes
  instead of up to 1024.

- bpo-26616: Fixed a bug in datetime.astimezone() method.

- bpo-21925: :func:`warnings.formatwarning` now catches exceptions on
  ``linecache.getline(...)`` to be able to log :exc:`ResourceWarning`
  emitted late during the Python shutdown process.

- bpo-24266: Ctrl+C during Readline history search now cancels the search
  mode when compiled with Readline 7.

- bpo-26560: Avoid potential ValueError in BaseHandler.start_response.
  Initial patch by Peter Inglesby.


- bpo-26313: _load_windows_store_certs fails if windows cert store is
  empty. Patch by Baji.


- bpo-26569: Fix :func:`pyclbr.readmodule` and :func:`pyclbr.readmodule_ex`
  to support importing packages.

- bpo-26499: Account for remaining Content-Length in HTTPResponse.readline()
  and read1(). Based on patch by Silent Ghost. Also document that
  HTTPResponse now supports these methods.

- bpo-25320: Handle sockets in directories unittest discovery is scanning.
  Patch from Victor van den Elzen.

- bpo-16181: cookiejar.http2time() now returns None if year is higher than

- bpo-26513: Fixes platform module detection of Windows Server

- bpo-23718: Fixed parsing time in week 0 before Jan 1.  Original patch by
  Tamás Bence Gedai.

- bpo-20589: Invoking Path.owner() and on Windows now raise
  NotImplementedError instead of ImportError.

- bpo-26177: Fixed the keys() method for Canvas and Scrollbar widgets.

- bpo-15068: Got rid of excessive buffering in the fileinput module. The
  bufsize parameter is no longer used.

- bpo-2202: Fix UnboundLocalError in
  AbstractDigestAuthHandler.get_algorithm_impls. Initial patch by Mathieu

- bpo-25718: Fixed pickling and copying the accumulate() iterator with total
  is None.

- bpo-26475: Fixed debugging output for regular expressions with the (?x)

- bpo-26457: Fixed the subnets() methods in IP network classes for the case
  when resulting prefix length is equal to maximal prefix length. Based on
  patch by Xiang Zhang.

- bpo-26385: Remove the file if the internal open() call in
  NamedTemporaryFile() fails. Patch by Silent Ghost.

- bpo-26402: Fix XML-RPC client to retry when the server shuts down a
  persistent connection.  This was a regression related to the new
  http.client.RemoteDisconnected exception in 3.5.0a4.

- bpo-25913: Leading ``<~`` is optional now in base64.a85decode() with
  adobe=True.  Patch by Swati Jaiswal.

- bpo-26186: Remove an invalid type check in importlib.util.LazyLoader.

- bpo-26367: importlib.__import__() raises SystemError like
  builtins.__import__() when ``level`` is specified but without an
  accompanying package specified.

- bpo-26309: In the "socketserver" module, shut down the request (closing
  the connected socket) when verify_request() returns false.  Patch by Aviv


- bpo-25939: On Windows open the cert store readonly in


- bpo-25995: os.walk() no longer uses FDs proportional to the tree depth.

- bpo-26117: The os.scandir() iterator now closes file descriptor not only
  when the iteration is finished, but when it was failed with error.

- bpo-25911: Restored support of bytes paths in os.walk() on Windows.

- bpo-26045: Add UTF-8 suggestion to error message when posting a non-
  Latin-1 string with http.client.

- bpo-12923: Reset FancyURLopener's redirect counter even if there is an
  exception. Based on patches by Brian Brazil and Daniel Rocco.

- bpo-25945: Fixed a crash when unpickle the functools.partial object with
  wrong state. Fixed a leak in failed functools.partial constructor. "args"
  and "keywords" attributes of functools.partial have now always types tuple
  and dict correspondingly.

- bpo-26202: copy.deepcopy() now correctly copies range() objects with non-
  atomic attributes.

- bpo-23076: Path.glob() now raises a ValueError if it's called with an
  invalid pattern. Patch by Thomas Nyberg.

- bpo-19883: Fixed possible integer overflows in zipimport.

- bpo-26227: On Windows, getnameinfo(), gethostbyaddr() and
  gethostbyname_ex() functions of the socket module now decode the hostname
  from the ANSI code page rather than UTF-8.

- bpo-26147: xmlrpc now works with strings not encodable with used non-UTF-8

- bpo-25935: Garbage collector now breaks reference loops with OrderedDict.

- bpo-16620: Fixed AttributeError in msilib.Directory.glob().

- bpo-26013: Added compatibility with broken protocol 2 pickles created in
  old Python 3 versions (3.4.3 and lower).

- bpo-25850: Use cross-compilation by default for 64-bit Windows.

- bpo-17633: Improve zipimport's support for namespace packages.

- bpo-24705: Fix sysconfig._parse_makefile not expanding ${} vars appearing
  before $() vars.

- bpo-22138: Fix mock.patch behavior when patching descriptors. Restore
  original values after patching. Patch contributed by Sean McCully.

- bpo-25672: In the ssl module, enable the SSL_MODE_RELEASE_BUFFERS mode
  option if it is safe to do so.

- bpo-26012: Don't traverse into symlinks for ``**`` pattern in

- bpo-24120: Ignore PermissionError when traversing a tree with
  pathlib.Path.[r]glob(). Patch by Ulrich Petri.

- bpo-25447: fileinput now uses sys.stdin as-is if it does not have a buffer
  attribute (restores backward compatibility).

- bpo-25447: Copying the lru_cache() wrapper object now always works,
  independedly from the type of the wrapped object (by returning the
  original object unchanged).

- bpo-24103: Fixed possible use after free in ElementTree.XMLPullParser.

- bpo-25860: os.fwalk() no longer skips remaining directories when error
  occurs. Original patch by Samson Lee.

- bpo-25914: Fixed and simplified OrderedDict.__sizeof__.

- bpo-25902: Fixed various refcount issues in ElementTree iteration.

- bpo-25717: Restore the previous behaviour of tolerating most fstat()
  errors when opening files.  This was a regression in 3.5a1, and stopped
  anonymous temporary files from working in special cases.

- bpo-24903: Fix regression in number of arguments compileall accepts when
  '-d' is specified.  The check on the number of arguments has been dropped
  completely as it never worked correctly anyway.

- bpo-25764: In the subprocess module, preserve any exception caused by
  fork() failure when preexec_fn is used.

- bpo-6478: _strptime's regexp cache now is reset after changing timezone
  with time.tzset().

- bpo-14285: When executing a package with the "python -m package" option,
  and package initialization fails, a proper traceback is now reported.  The
  "runpy" module now lets exceptions from package initialization pass back
  to the caller, rather than raising ImportError.

- bpo-19771: Also in runpy and the "-m" option, omit the irrelevant message
  ". . . is a package and cannot be directly executed" if the package could
  not even be initialized (e.g. due to a bad ``*.pyc`` file).

- bpo-25177: Fixed problem with the mean of very small and very large
  numbers. As a side effect, statistics.mean and statistics.variance should
  be significantly faster.

- bpo-25718: Fixed copying object with state with boolean value is false.

- bpo-10131: Fixed deep copying of minidom documents.  Based on patch by
  Marian Ganisin.

- bpo-25725: Fixed a reference leak in pickle.loads() when unpickling
  invalid data including tuple instructions.

- bpo-25663: In the Readline completer, avoid listing duplicate global
  names, and search the global namespace before searching builtins.

- bpo-25688: Fixed file leak in ElementTree.iterparse() raising an error.

- bpo-23914: Fixed SystemError raised by unpickler on broken pickle data.

- bpo-25691: Fixed crash on deleting ElementTree.Element attributes.

- bpo-25624: ZipFile now always writes a ZIP_STORED header for directory
  entries.  Patch by Dingyuan Wang.

- Skip getaddrinfo if host is already resolved. Patch by A. Jesse Jiryu

- bpo-26050: Add asyncio.StreamReader.readuntil() method. Patch by Марк

- bpo-25924: Avoid unnecessary serialization of getaddrinfo(3) calls on OS X
  versions 10.5 or higher.  Original patch by A. Jesse Jiryu Davis.

- bpo-26406: Avoid unnecessary serialization of getaddrinfo(3) calls on
  current versions of OpenBSD and NetBSD.  Patch by A. Jesse Jiryu Davis.

- bpo-26848: Fix asyncio/subprocess.communicate() to handle empty input.
  Patch by Jack O'Connor.

- bpo-27040: Add loop.get_exception_handler method

- bpo-27041: asyncio: Add loop.create_future method

- bpo-27223: asyncio: Fix _read_ready and _write_ready to respect
  _conn_lost. Patch by Łukasz Langa.

- bpo-22970: asyncio: Fix inconsistency cancelling Condition.wait. Patch by
  David Coles.


- bpo-5124: Paste with text selected now replaces the selection on X11. This
  matches how paste works on Windows, Mac, most modern Linux apps, and ttk
  widgets. Original patch by Serhiy Storchaka.

- bpo-24759: Make clear in idlelib.idle_test.__init__ that the directory is
  a private implementation of test.test_idle and tool for maintainers.

- bpo-27196: Stop 'ThemeChanged' warnings when running IDLE tests. These
  persisted after other warnings were suppressed in #20567. Apply Serhiy
  Storchaka's update_idletasks solution to four test files. Record this
  additional advice in idle_test/README.txt

- bpo-20567: Revise idle_test/README.txt with advice about avoiding tk
  warning messages from tests.  Apply advice to several IDLE tests.

- bpo-27117: Make colorizer htest and turtledemo work with dark themes. Move
  code for configuring text widget colors to a new function.

- bpo-26673: When tk reports font size as 0, change to size 10. Such fonts
  on Linux prevented the configuration dialog from opening.

- bpo-21939: Add test for IDLE's percolator. Original patch by Saimadhav

- bpo-21676: Add test for IDLE's replace dialog. Original patch by Saimadhav

- bpo-18410: Add test for IDLE's search dialog. Original patch by Westley

- bpo-21703: Add test for IDLE's undo delegator. Original patch by Saimadhav
  Heblikar .

- bpo-27044: Add ConfigDialog.remove_var_callbacks to stop memory leaks.

- bpo-23977: Add more asserts to test_delegator.

- bpo-20640: Add tests for idlelib.configHelpSourceEdit. Patch by Saimadhav

- In the 'IDLE-console differences' section of the IDLE doc, clarify how
  running with IDLE affects sys.modules and the standard streams.

- bpo-25507: fix incorrect change in IOBinding that prevented printing.
  Augment IOBinding htest to include all major IOBinding functions.

- bpo-25905: Revert unwanted conversion of ' to ’ RIGHT SINGLE QUOTATION
  MARK in README.txt and open this and NEWS.txt with 'ascii'. Re-encode
  CREDITS.txt to utf-8 and open it with 'utf-8'.


- bpo-19489: Moved the search box from the sidebar to the header and footer
  of each page. Patch by Ammar Askar.

- bpo-24136: Document the new PEP 448 unpacking syntax of 3.5.

- bpo-26736: Used HTTPS for external links in the documentation if possible.

- bpo-6953: Rework the Readline module documentation to group related
  functions together, and add more details such as what underlying Readline
  functions and variables are accessed.

- bpo-23606: Adds note to ctypes documentation regarding cdll.msvcrt.

- bpo-25500: Fix documentation to not claim that __import__ is searched for
  in the global scope.

- bpo-26014: Update 3.x packaging documentation: * "See also" links to the
  new docs are now provided in the legacy pages * links to setuptools
  documentation have been updated


- bpo-21916: Added tests for the turtle module.  Patch by ingrid, Gregory
  Loyse and Jelle Zijlstra.

- bpo-26523: The multiprocessing thread pool (multiprocessing.dummy.Pool)
  was untested.

- bpo-26015: Added new tests for pickling iterators of mutable sequences.

- bpo-26325: Added to check that no
  ResourceWarning is emitted.

- bpo-25940: Changed test_ssl to use  This
  avoids relying on, which recently changed root certificate.

- bpo-25616: Tests for OrderedDict are extracted from test_collections into
  separate file test_ordered_dict.

- bpo-26583: Skip test_timestamp_overflow in test_import if bytecode files
  cannot be written.


- bpo-26884: Fix linking extension modules for cross builds. Patch by Xavier
  de Gaye.

- bpo-22359: Disable the rules for running _freeze_importlib and pgen when
  cross- compiling.  The output of these programs is normally saved with the
  source code anyway, and is still regenerated when doing a native build.
  Patch by Xavier de Gaye.

- bpo-27229: Fix the cross-compiling pgen rule for in-tree builds.  Patch by
  Xavier de Gaye.

- bpo-21668: Link audioop, _datetime, _ctypes_test modules to libm, except
  on Mac OS X. Patch written by Xavier de Gaye.

- bpo-25702: A --with-lto configure option has been added that will enable
  link time optimizations at build time during a make profile-opt. Some
  compilers and toolchains are known to not produce stable code when using
  LTO, be sure to test things thoroughly before relying on it. It can
  provide a few % speed up over profile-opt alone.

- bpo-26624: Adds validation of ucrtbase[d].dll version with warning for old

- bpo-17603: Avoid error about nonexistant fileblocks.o file by using a
  lower-level check for st_blocks in struct stat.

- bpo-26079: Fixing the build output folder for tix- Patch by Bjoern

- bpo-26465: Update Windows builds to use OpenSSL 1.0.2g.

- bpo-24421: Compile Modules/_math.c once, before building extensions.
  Previously it could fail to compile properly if the math and cmath builds
  were concurrent.

- bpo-25348: Added ``--pgo`` and ``--pgo-job`` arguments to
  ``PCbuild\build.bat`` for building with Profile-Guided Optimization.  The
  old ``PCbuild\build_pgo.bat`` script is now deprecated, and simply calls
  ``PCbuild\build.bat --pgo %*``.

- bpo-25827: Add support for building with ICC to ``configure``, including a
  new ``--with-icc`` flag.

- bpo-25696: Fix installation of Python on UNIX with make -j9.

- bpo-26930: Update OS X 10.5+ 32-bit-only installer to build and link with
  OpenSSL 1.0.2h.

- bpo-26268: Update Windows builds to use OpenSSL 1.0.2f.

- bpo-25136: Support Apple Xcode 7's new textual SDK stub libraries.

- bpo-24324: Do not enable unreachable code warnings when using gcc as the
  option does not work correctly in older versions of gcc and has been
  silently removed as of gcc-4.5.


- bpo-27053: Updates to correctly generate library ZIP file.

- bpo-26268: Update the script to handle OpenSSL releases
  that don't include the contents of the include directory (that is, 1.0.2e
  and later).

- bpo-26071: bdist_wininst created binaries fail to start and find 32bit

- bpo-26073: Update the list of magic numbers in launcher

- bpo-26065: Excludes venv from library when generating embeddable distro.


- bpo-26799: Fix don't get C types once when the Python code
  is loaded, but get C types on demand. The C types can change if python- is loaded before the Python executable. Patch written by Thomas

- bpo-26271: Fix the Freeze tool to properly use flags passed through
  configure. Patch by Daniel Shaulov.

- bpo-26489: Add dictionary unpacking support to Tools/parser/
  Patch by Guo Ci Teo.

- bpo-26316: Fix variable name typo in Argument Clinic.


- bpo-17500: Remove unused and outdated icons. (See also:

What's New in Python 3.5.1 final?

*Release date: 2015-12-06*

Core and Builtins

- bpo-25709: Fixed problem with in-place string concatenation and utf-8


- bpo-25715: Python 3.5.1 installer shows wrong upgrade path and incorrect
  logic for launcher detection.

What's New in Python 3.5.1 release candidate 1?

*Release date: 2015-11-22*

Core and Builtins

- bpo-25630: Fix a possible segfault during argument parsing in functions
  that accept filesystem paths.

- bpo-23564: Fixed a partially broken sanity check in the _posixsubprocess
  internals regarding how fds_to_pass were passed to the child.  The bug had
  no actual impact as already avoided it.

- bpo-25388: Fixed tokenizer crash when processing undecodable source code
  with a null byte.

- bpo-25462: The hash of the key now is calculated only once in most
  operations in C implementation of OrderedDict.

- bpo-22995: Default implementation of __reduce__ and __reduce_ex__ now
  rejects builtin types with not defined __new__.

- bpo-25555: Fix parser and AST: fill lineno and col_offset of "arg" node
  when compiling AST from Python objects.

- bpo-24802: Avoid buffer overreads when int(), float(), compile(), exec()
  and eval() are passed bytes-like objects.  These objects are not
  necessarily terminated by a null byte, but the functions assumed they

- bpo-24726: Fixed a crash and leaking NULL in repr() of OrderedDict that
  was mutated by direct calls of dict methods.

- bpo-25449: Iterating OrderedDict with keys with unstable hash now raises
  KeyError in C implementations as well as in Python implementation.

- bpo-25395: Fixed crash when highly nested OrderedDict structures were
  garbage collected.

- bpo-25274: sys.setrecursionlimit() now raises a RecursionError if the new
  recursion limit is too low depending at the current recursion depth.
  Modify also the "lower-water mark" formula to make it monotonic. This mark
  is used to decide when the overflowed flag of the thread state is reset.

- bpo-24402: Fix input() to prompt to the redirected stdout when
  sys.stdout.fileno() fails.

- bpo-24806: Prevent builtin types that are not allowed to be subclassed
  from being subclassed through multiple inheritance.

- bpo-24848: Fixed a number of bugs in UTF-7 decoding of misformed data.

- bpo-25280: Import trace messages emitted in verbose (-v) mode are no
  longer formatted twice.

- bpo-25003: On Solaris 11.3 or newer, os.urandom() now uses the getrandom()
  function instead of the getentropy() function. The getentropy() function
  is blocking to generate very good quality entropy, os.urandom() doesn't
  need such high- quality entropy.

- bpo-25182: The stdprinter (used as sys.stderr before the io module is
  imported at startup) now uses the backslashreplace error handler.

- bpo-25131: Make the line number and column offset of set/dict literals and
  comprehensions correspond to the opening brace.

- bpo-25150: Hide the private _Py_atomic_xxx symbols from the public
  Python.h header to fix a compilation error with OpenMP.
  PyThreadState_GET() becomes an alias to PyThreadState_Get() to avoid ABI


- bpo-25626: Change three zlib functions to accept sizes that fit in
  Py_ssize_t, but internally cap those sizes to UINT_MAX.  This resolves a
  regression in 3.5 where failed to read chunks larger than
  2 or 4 GiB.  The change affects the zlib.Decompress.decompress()
  max_length parameter, the zlib.decompress() bufsize parameter, and the
  zlib.Decompress.flush() length parameter.

- bpo-25583: Avoid incorrect errors raised by os.makedirs(exist_ok=True)
  when the OS gives priority to errors such as EACCES over EEXIST.

- bpo-25593: Change semantics of EventLoop.stop() in asyncio.

- bpo-6973: When we know a subprocess.Popen process has died, do not allow
  the send_signal(), terminate(), or kill() methods to do anything as they
  could potentially signal a different process.

- bpo-25590: In the Readline completer, only call getattr() once per

- bpo-25498: Fix a crash when garbage-collecting ctypes objects created by
  wrapping a memoryview.  This was a regression made in 3.5a1.  Based on
  patch by Eryksun.

- bpo-25584: Added "escape" to the __all__ list in the glob module.

- bpo-25584: Fixed recursive glob() with patterns starting with ``**``.

- bpo-25446: Fix regression in smtplib's AUTH LOGIN support.

- bpo-18010: Fix the pydoc web server's module search function to handle
  exceptions from importing packages.

- bpo-25554: Got rid of circular references in regular expression parsing.

- bpo-25510: fileinput.FileInput.readline() now returns b'' instead of '' at
  the end if the FileInput was opened with binary mode. Patch by Ryosuke

- bpo-25503: Fixed inspect.getdoc() for inherited docstrings of properties.
  Original patch by John Mark Vandenberg.

- bpo-25515: Always use os.urandom as a source of randomness in uuid.uuid4.

- bpo-21827: Fixed textwrap.dedent() for the case when largest common
  whitespace is a substring of smallest leading whitespace. Based on patch
  by Robert Li.

- bpo-25447: The lru_cache() wrapper objects now can be copied and pickled
  (by returning the original object unchanged).

- bpo-25390: typing: Don't crash on Union[str, Pattern].

- bpo-25441: asyncio: Raise error from drain() when socket is closed.

- bpo-25410: Cleaned up and fixed minor bugs in C implementation of

- bpo-25411: Improved Unicode support in SMTPHandler through better use of
  the email package. Thanks to user simon04 for the patch.

- bpo-25407: Remove mentions of the formatter module being removed in Python

- bpo-25406: Fixed a bug in C implementation of OrderedDict.move_to_end()
  that caused segmentation fault or hang in iterating after moving several
  items to the start of ordered dict.

- bpo-25364: zipfile now works in threads disabled builds.

- bpo-25328: smtpd's SMTPChannel now correctly raises a ValueError if both
  decode_data and enable_SMTPUTF8 are set to true.

- bpo-25316: distutils raises OSError instead of DistutilsPlatformError when
  MSVC is not installed.

- bpo-25380: Fixed protocol for the STACK_GLOBAL opcode in

- bpo-23972: Updates asyncio datagram create method allowing reuseport and
  reuseaddr socket options to be set prior to binding the socket. Mirroring
  the existing asyncio create_server method the reuseaddr option for
  datagram sockets defaults to True if the O/S is 'posix' (except if the
  platform is Cygwin). Patch by Chris Laws.

- bpo-25304: Add asyncio.run_coroutine_threadsafe().  This lets you submit a
  coroutine to a loop from another thread, returning a
  concurrent.futures.Future.  By Vincent Michel.

- bpo-25232: Fix CGIRequestHandler to split the query from the URL at the
  first question mark (?) rather than the last. Patch from Xiang Zhang.

- bpo-24657: Prevent CGIRequestHandler from collapsing slashes in the query
  part of the URL as if it were a path. Patch from Xiang Zhang.

- bpo-24483: C implementation of functools.lru_cache() now calculates key's
  hash only once.

- bpo-22958: Constructor and update method of weakref.WeakValueDictionary
  now accept the self and the dict keyword arguments.

- bpo-22609: Constructor of collections.UserDict now accepts the self
  keyword argument.

- bpo-25111: Fixed comparison of traceback.FrameSummary.

- bpo-25262: Added support for BINBYTES8 opcode in Python implementation of
  unpickler. Highest 32 bits of 64-bit size for BINUNICODE8 and BINBYTES8
  opcodes no longer silently ignored on 32-bit platforms in C

- bpo-25034: Fix string.Formatter problem with auto-numbering and nested
  format_specs. Patch by Anthon van der Neut.

- bpo-25233: Rewrite the guts of asyncio.Queue and asyncio.Semaphore to be
  more understandable and correct.

- bpo-25203: Failed readline.set_completer_delims() no longer left the
  module in inconsistent state.

- bpo-23600: Default implementation of tzinfo.fromutc() was returning wrong
  results in some cases.

- bpo-23329: Allow the ssl module to be built with older versions of

- Prevent overflow in _Unpickler_Read.

- bpo-25047: The XML encoding declaration written by Element Tree now
  respects the letter case given by the user. This restores the ability to
  write encoding names in uppercase like "UTF-8", which worked in Python 2.

- bpo-25135: Make deque_clear() safer by emptying the deque before clearing.
  This helps avoid possible reentrancy issues.

- bpo-19143: platform module now reads Windows version from kernel32.dll to
  avoid compatibility shims.

- bpo-25092: Fix datetime.strftime() failure when errno was already set to

- bpo-23517: Fix rounding in fromtimestamp() and utcfromtimestamp() methods
  of datetime.datetime: microseconds are now rounded to nearest with ties
  going to nearest even integer (ROUND_HALF_EVEN), instead of being rounding
  towards minus infinity (ROUND_FLOOR). It's important that these methods
  use the same rounding mode than datetime.timedelta to keep the property:
  (datetime(1970,1,1) + timedelta(seconds=t)) ==
  datetime.utcfromtimestamp(t). It also the rounding mode used by
  round(float) for example.

- bpo-25155: Fix and datetime.datetime.utcnow() on
  Windows to support date after year 2038. It was a regression introduced in
  Python 3.5.0.

- bpo-25108: Omitted internal frames in traceback functions print_stack(),
  format_stack(), and extract_stack() called without arguments.

- bpo-25118: Fix a regression of Python 3.5.0 in os.waitpid() on Windows.

- bpo-24684: socket.socket.getaddrinfo() now calls
  PyUnicode_AsEncodedString() instead of calling the encode() method of the
  host, to handle correctly custom string with an encode() method which
  doesn't return a byte string. The encoder of the IDNA codec is now called
  directly instead of calling the encode() method of the string.

- bpo-25060: Correctly compute stack usage of the BUILD_MAP opcode.

- bpo-24857: Comparing call_args to a long sequence now correctly returns a
  boolean result instead of raising an exception.  Patch by A Kaptur.

- bpo-23144: Make sure that HTMLParser.feed() returns all the data, even
  when convert_charrefs is True.

- bpo-24982: shutil.make_archive() with the "zip" format now adds entries
  for directories (including empty directories) in ZIP file.

- bpo-25019: Fixed a crash caused by setting non-string key of expat parser.
  Based on patch by John Leitch.

- bpo-16180: Exit pdb if file has syntax error, instead of trapping user in
  an infinite loop.  Patch by Xavier de Gaye.

- bpo-24891: Fix a race condition at Python startup if the file descriptor
  of stdin (0), stdout (1) or stderr (2) is closed while Python is creating
  sys.stdin, sys.stdout and sys.stderr objects. These attributes are now set
  to None if the creation of the object failed, instead of raising an
  OSError exception. Initial patch written by Marco Paolini.

- bpo-24992: Fix error handling and a race condition (related to garbage
  collection) in collections.OrderedDict constructor.

- bpo-24881: Fixed setting binary mode in Python implementation of FileIO on
  Windows and Cygwin.  Patch from Akira Li.

- bpo-25578: Fix (another) memory leak in SSLSocket.getpeercer().

- bpo-25530: Disable the vulnerable SSLv3 protocol by default when creating

- bpo-25569: Fix memory leak in SSLSocket.getpeercert().

- bpo-25471: Sockets returned from accept() shouldn't appear to be

- bpo-25319: When threading.Event is reinitialized, the underlying condition
  should use a regular lock rather than a recursive lock.

- bpo-21112: Fix regression in unittest.expectedFailure on subclasses. Patch
  from Berker Peksag.

- bpo-24764: cgi.FieldStorage.read_multi() now ignores the Content-Length
  header in part headers. Patch written by Peter Landry and reviewed by
  Pierre Quentel.

- bpo-24913: Fix overrun error in deque.index(). Found by John Leitch and
  Bryce Darling.

- bpo-24774: Fix docstring in http.server.test. Patch from Chiu-Hsiang Hsu.

- bpo-21159: Improve message in
  configparser.InterpolationMissingOptionError. Patch from Łukasz Langa.

- bpo-20362: Honour TestCase.longMessage correctly in assertRegex. Patch
  from Ilia Kurenkov.

- bpo-23572: Fixed functools.singledispatch on classes with falsy
  metaclasses.  Patch by Ethan Furman.

- asyncio: ensure_future() now accepts awaitable objects.


- bpo-15348: Stop the debugger engine (normally in a user process) before
  closing the debugger window (running in the IDLE process). This prevents
  the RuntimeErrors that were being caught and ignored.

- bpo-24455: Prevent IDLE from hanging when a) closing the shell while the
  debugger is active (15347); b) closing the debugger with the [X] button
  (15348); and c) activating the debugger when already active (24455). The
  patch by Mark Roseman does this by making two changes. 1. Suspend and
  resume the gui.interaction method with the tcl vwait mechanism intended
  for this purpose (instead of root.mainloop & .quit). 2. In, allow
  any existing interaction to terminate first.

- Change 'The program' to 'Your program' in an IDLE 'kill program?' message
  to make it clearer that the program referred to is the currently running
  user program, not IDLE itself.

- bpo-24750: Improve the appearance of the IDLE editor window status bar.
  Patch by Mark Roseman.

- bpo-25313: Change the handling of new built-in text color themes to better
  address the compatibility problem introduced by the addition of IDLE Dark.
  Consistently use the revised idleConf.CurrentTheme everywhere in idlelib.

- bpo-24782: Extension configuration is now a tab in the IDLE Preferences
  dialog rather than a separate dialog.  The former tabs are now a sorted
  list.  Patch by Mark Roseman.

- bpo-22726: Re-activate the config dialog help button with some content
  about the other buttons and the new IDLE Dark theme.

- bpo-24820: IDLE now has an 'IDLE Dark' built-in text color theme. It is
  more or less IDLE Classic inverted, with a cobalt blue background.
  Strings, comments, keywords, ... are still green, red, orange, ... . To
  use it with IDLEs released before November 2015, hit the 'Save as New
  Custom Theme' button and enter a new name, such as 'Custom Dark'.  The
  custom theme will work with any IDLE release, and can be modified.

- bpo-25224: README.txt is now an idlelib index for IDLE developers and
  curious users. The previous user content is now in the IDLE doc chapter.
  'IDLE' now means 'Integrated Development and Learning Environment'.

- bpo-24820: Users can now set breakpoint colors in Settings -> Custom
  Highlighting. Original patch by Mark Roseman.

- bpo-24972: Inactive selection background now matches active selection
  background, as configured by users, on all systems.  Found items are now
  always highlighted on Windows.  Initial patch by Mark Roseman.

- bpo-24570: Idle: make calltip and completion boxes appear on Macs affected
  by a tk regression.  Initial patch by Mark Roseman.

- bpo-24988: Idle ScrolledList context menus (used in debugger) now work on
  Mac Aqua. Patch by Mark Roseman.

- bpo-24801: Make right-click for context menu work on Mac Aqua. Patch by
  Mark Roseman.

- bpo-25173: Associate tkinter messageboxes with a specific widget. For Mac
  OSX, make them a 'sheet'.  Patch by Mark Roseman.

- bpo-25198: Enhance the initial html viewer now used for Idle Help. *
  Properly indent fixed-pitch text (patch by Mark Roseman). * Give code
  snippet a very Sphinx- like light blueish-gray background. * Re-use
  initial width and height set by users for shell and editor. * When the
  Table of Contents (TOC) menu is used, put the section header at the top of
  the screen.

- bpo-25225: Condense and rewrite Idle doc section on text colors.

- bpo-21995: Explain some differences between IDLE and console Python.

- bpo-22820: Explain need for *print* when running file from Idle editor.

- bpo-25224: Doc: augment Idle feature list and no-subprocess section.

- bpo-25219: Update doc for Idle command line options. Some were missing and
  notes were not correct.

- bpo-24861: Most of idlelib is private and subject to change. Use
  idleib.idle.* to start Idle. See idlelib.__init__.__doc__.

- bpo-25199: Idle: add synchronization comments for future maintainers.

- bpo-16893: Replace help.txt with help.html for Idle doc display. The new
  idlelib/help.html is rstripped Doc/build/html/library/idle.html. It looks
  better than help.txt and will better document Idle as released. The
  tkinter html viewer that works for this file was written by Mark Roseman.
  The now unused EditorWindow.HelpDialog class and helt.txt file are

- bpo-24199: Deprecate unused idlelib.idlever with possible removal in 3.6.

- bpo-24790: Remove extraneous code (which also create 2 & 3 conflicts).


- bpo-22558: Add remaining doc links to source code for Python-coded
  modules. Patch by Yoni Lavi.

- bpo-12067: Rewrite Comparisons section in the Expressions chapter of the
  language reference. Some of the details of comparing mixed types were
  incorrect or ambiguous. NotImplemented is only relevant at a lower level
  than the Expressions chapter. Added details of comparing range() objects,
  and default behaviour and consistency suggestions for user-defined
  classes. Patch from Andy Maier.

- bpo-24952: Clarify the default size argument of stack_size() in the
  "threading" and "_thread" modules. Patch from Mattip.

- bpo-23725: Overhaul tempfile docs. Note deprecated status of mktemp. Patch
  from Zbigniew Jędrzejewski-Szmek.

- bpo-24808: Update the types of some PyTypeObject fields.  Patch by Joseph

- bpo-22812: Fix unittest discovery examples. Patch from Pam McA'Nulty.


- bpo-25449: Added tests for OrderedDict subclasses.

- bpo-25099: Make test_compileall not fail when an entry on sys.path cannot
  be written to (commonly seen in administrative installs on Windows).

- bpo-23919: Prevents assert dialogs appearing in the test suite.

- ``PCbuild\rt.bat`` now accepts an unlimited number of arguments to pass
  along to  Previously there was a limit of 9.


- bpo-24915: Add LLVM support for PGO builds and use the test suite to
  generate the profile data. Initial patch by Alecsandru Patrascu of Intel.

- bpo-24910: Windows MSIs now have unique display names.

- bpo-24986: It is now possible to build Python on Windows without errors
  when external libraries are not available.


- bpo-25450: Updates shortcuts to start Python in installation directory.

- bpo-25164: Changes default all-users install directory to match per-user

- bpo-25143: Improves installer error messages for unsupported platforms.

- bpo-25163: Display correct directory in installer when using non-default

- bpo-25361: Disables use of SSE2 instructions in Windows 32-bit build

- bpo-25089: Adds logging to installer for case where launcher is not
  selected on upgrade.

- bpo-25165: Windows uninstallation should not remove launcher if other
  versions remain

- bpo-25112: py.exe launcher is missing icons

- bpo-25102: Windows installer does not precompile for -O or -OO.

- bpo-25081: Makes Back button in installer go back to upgrade page when

- bpo-25091: Increases font size of the installer.

- bpo-25126: Clarifies that the non-web installer will download some

- bpo-25213: Restores requestedExecutionLevel to manifest to disable UAC

- bpo-25022: Removed very outdated PC/example_nt/ directory.


- bpo-25440: Fix output of python-config --extension-suffix.

What's New in Python 3.5.0 final?

*Release date: 2015-09-13*


- bpo-25071: Windows installer should not require TargetDir parameter when
  installing quietly.

What's New in Python 3.5.0 release candidate 4?

*Release date: 2015-09-09*


- bpo-25029: Fixes MemoryError in test_strptime.


- bpo-25027: Reverts partial-static build options and adds vcruntime140.dll
  to Windows installation.

What's New in Python 3.5.0 release candidate 3?

*Release date: 2015-09-07*

Core and Builtins

- bpo-24305: Prevent import subsystem stack frames from being counted by the
  warnings.warn(stacklevel=) parameter.

- bpo-24912: Prevent __class__ assignment to immutable built-in objects.

- bpo-24975: Fix AST compilation for PEP 448 syntax.


- bpo-24917: time_strftime() buffer over-read.

- bpo-24748: To resolve a compatibility problem found with py2exe and
  pywin32, imp.load_dynamic() once again ignores previously loaded modules
  to support Python modules replacing themselves with extension modules.
  Patch by Petr Viktorin.

- bpo-24635: Fixed a bug in where isinstance([], typing.Iterable)
  would return True once, then False on subsequent calls.

- bpo-24989: Fixed buffer overread in BytesIO.readline() if a position is
  set beyond size.  Based on patch by John Leitch.

- bpo-24913: Fix overrun error in deque.index(). Found by John Leitch and
  Bryce Darling.

What's New in Python 3.5.0 release candidate 2?

*Release date: 2015-08-25*

Core and Builtins

- bpo-24769: Interpreter now starts properly when dynamic loading is
  disabled.  Patch by Petr Viktorin.

- bpo-21167: NAN operations are now handled correctly when python is
  compiled with ICC even if -fp-model strict is not specified.

- bpo-24492: A "package" lacking a __name__ attribute when trying to perform
  a ``from .. import ...`` statement will trigger an ImportError instead of
  an AttributeError.


- bpo-24847: Removes vcruntime140.dll dependency from Tcl/Tk.

- bpo-24839: platform._syscmd_ver raises DeprecationWarning

- bpo-24867: Fix Task.get_stack() for 'async def' coroutines

What's New in Python 3.5.0 release candidate 1?

*Release date: 2015-08-09*

Core and Builtins

- bpo-24667: Resize odict in all cases that the underlying dict resizes.


- bpo-24824: Signatures of codecs.encode() and codecs.decode() now are
  compatible with pydoc.

- bpo-24634: Importing uuid should not try to load libc on Windows

- bpo-24798: doesn't properly support manifests

- bpo-4395: Better testing and documentation of binary operators. Patch by
  Martin Panter.

- bpo-23973: Update from GitHub repo.

- bpo-23004: mock_open() now reads binary data correctly when the type of
  read_data is bytes.  Initial patch by Aaron Hill.

- bpo-23888: Handle fractional time in cookie expiry. Patch by ssh.

- bpo-23652: Make it possible to compile the select module against the libc
  headers from the Linux Standard Base, which do not include some EPOLL
  macros.  Patch by Matt Frank.

- bpo-22932: Fix timezones in email.utils.formatdate. Patch from Dmitry

- bpo-23779: imaplib raises TypeError if authenticator tries to abort. Patch
  from Craig Holmquist.

- bpo-23319: Fix ctypes.BigEndianStructure, swap correctly bytes. Patch
  written by Matthieu Gautier.

- bpo-23254: Document how to close the TCPServer listening socket. Patch
  from Martin Panter.

- bpo-19450: Update Windows and OS X installer builds to use SQLite 3.8.11.

- bpo-17527: Add PATCH to wsgiref.validator. Patch from Luca Sbardella.

- bpo-24791: Fix grammar regression for call syntax: 'g(\*a or b)'.


- bpo-23672: Allow Idle to edit and run files with astral chars in name.
  Patch by Mohd Sanad Zaki Rizvi.

- bpo-24745: Idle editor default font. Switch from Courier to platform-
  sensitive TkFixedFont.  This should not affect current customized font
  selections.  If there is a problem, edit $HOME/.idlerc/config-main.cfg and
  remove 'fontxxx' entries from [Editor Window].  Patch by Mark Roseman.

- bpo-21192: Idle editor. When a file is run, put its name in the restart
  bar. Do not print false prompts. Original patch by Adnan Umer.

- bpo-13884: Idle menus. Remove tearoff lines. Patch by Roger Serwy.


- bpo-24129: Clarify the reference documentation for name resolution. This
  includes removing the assumption that readers will be familiar with the
  name resolution scheme Python used prior to the introduction of lexical
  scoping for function namespaces. Patch by Ivan Levkivskyi.

- bpo-20769: Improve reload() docs. Patch by Dorian Pula.

- bpo-23589: Remove duplicate sentence from the FAQ.  Patch by Yongzhi Pan.

- bpo-24729: Correct IO tutorial to match implementation regarding encoding
  parameter to open function.


- bpo-24751: When running regrtest with the ``-w`` command line option, a
  test run is no longer marked as a failure if all tests succeed when re-

What's New in Python 3.5.0 beta 4?

*Release date: 2015-07-26*

Core and Builtins

- bpo-23573: Restored optimization of bytes.rfind() and bytearray.rfind()
  for single-byte argument on Linux.

- bpo-24569: Make PEP 448 dictionary evaluation more consistent.

- bpo-24583: Fix crash when set is mutated while being updated.

- bpo-24407: Fix crash when dict is mutated while being updated.

- bpo-24619: New approach for tokenizing async/await. As a consequence, it
  is now possible to have one-line 'async def foo(): await ..' functions.

- bpo-24687: Plug refleak on SyntaxError in function parameters annotations.

- bpo-15944: memoryview: Allow arbitrary formats when casting to bytes.
  Patch by Martin Panter.


- bpo-23441: rcompleter now prints a tab character instead of displaying
  possible completions for an empty word.  Initial patch by Martin Sekera.

- bpo-24683: Fixed crashes in _json functions called with arguments of
  inappropriate type.

- bpo-21697: shutil.copytree() now correctly handles symbolic links that
  point to directories.  Patch by Eduardo Seabra and Thomas Kluyver.

- bpo-14373: Fixed segmentation fault when gc.collect() is called during
  constructing lru_cache (C implementation).

- bpo-24695: Fix a regression in traceback.print_exception().  If
  exc_traceback is None we shouldn't print a traceback header like described
  in the documentation.

- bpo-24620: Random.setstate() now validates the value of state last

- bpo-22485: Fixed an issue that caused `inspect.getsource` to return
  incorrect results on nested functions.

- bpo-22153: Improve unittest docs. Patch from Martin Panter and evilzero.

- bpo-24580: Symbolic group references to open group in re patterns now are
  explicitly forbidden as well as numeric group references.

- bpo-24206: Fixed __eq__ and __ne__ methods of inspect classes.

- bpo-24631: Fixed regression in the timeit module with multiline setup.

- bpo-18622: unittest.mock.mock_open().reset_mock would recurse infinitely.
  Patch from Nicola Palumbo and Laurent De Buyst.

- bpo-23661: unittest.mock side_effects can now be exceptions again. This
  was a regression vs Python 3.4. Patch from Ignacio Rossi

- bpo-24608: now always returns bytes, not str.

- bpo-18684: Fixed reading out of the buffer in the re module.

- bpo-24259: tarfile now raises a ReadError if an archive is truncated
  inside a data segment.

- bpo-15014: SMTP.auth() and SMTP.login() now support RFC 4954's optional
  initial- response argument to the SMTP AUTH command.

- bpo-24669: Fix inspect.getsource() for 'async def' functions. Patch by Kai

- bpo-24688: ast.get_docstring() for 'async def' functions.


- bpo-24603: Update Windows builds and OS X 10.5 installer to use OpenSSL

What's New in Python 3.5.0 beta 3?

*Release date: 2015-07-05*

Core and Builtins

- bpo-24467: Fixed possible buffer over-read in bytearray. The bytearray
  object now always allocates place for trailing null byte and it's buffer
  now is always null-terminated.

- Upgrade to Unicode 8.0.0.

- bpo-24345: Add Py_tp_finalize slot for the stable ABI.

- bpo-24400: Introduce a distinct type for PEP 492 coroutines; add
  types.CoroutineType, inspect.getcoroutinestate,
  inspect.getcoroutinelocals; coroutines no longer use CO_GENERATOR flag;
  sys.set_coroutine_wrapper works only for 'async def' coroutines;
  inspect.iscoroutine no longer uses, it's
  intended to test for pure 'async def' coroutines only; add new opcode:
  GET_YIELD_FROM_ITER; fix generators wrapper used in types.coroutine to be
  instance of; and can no longer be used to detect generator-based
  coroutines--use inspect.isawaitable instead.

- bpo-24450: Add gi_yieldfrom to generators and cr_await to coroutines.
  Contributed by Benno Leslie and Yury Selivanov.

- bpo-19235: Add new RecursionError exception. Patch by Georg Brandl.


- bpo-21750: mock_open.read_data can now be read from each instance, as it
  could in Python 3.3.

- bpo-24552: Fix use after free in an error case of the _pickle module.

- bpo-24514: tarfile now tolerates number fields consisting of only

- bpo-19176: Fixed doctype() related bugs in C implementation of
  ElementTree. A deprecation warning no longer issued by XMLParser subclass
  with default doctype() method.  Direct call of doctype() now issues a
  warning.  Parser's doctype() now is not called if target's doctype() is
  called.  Based on patch by Martin Panter.

- bpo-20387: Restore semantic round-trip correctness in tokenize/untokenize
  for tab- indented blocks.

- bpo-24456: Fixed possible buffer over-read in adpcm2lin() and lin2adpcm()
  functions of the audioop module.

- bpo-24336: The contextmanager decorator now works with functions with
  keyword arguments called "func" and "self".  Patch by Martin Panter.

- bpo-24522: Fix possible integer overflow in json accelerator module.

- bpo-24489: ensure a previously set C errno doesn't disturb cmath.polar().

- bpo-24408: Fixed AttributeError in measure() and metrics() methods of

- bpo-14373: C implementation of functools.lru_cache() now can be used with

- bpo-24347: Set KeyError if PyDict_GetItemWithError returns NULL.

- bpo-24348: Drop superfluous incref/decref.

- bpo-24359: Check for changed OrderedDict size during iteration.

- bpo-24368: Support keyword arguments in OrderedDict methods.

- bpo-24362: Simplify the C OrderedDict fast nodes resize logic.

- bpo-24377: Fix a ref leak in OrderedDict.__repr__.

- bpo-24369: Defend against key-changes during iteration.


- bpo-24373: _testmultiphase and xxlimited now use tp_traverse and
  tp_finalize to avoid reference leaks encountered when combining tp_dealloc
  with PyType_FromSpec (see issue #16690 for details)


- bpo-24458: Update documentation to cover multi-phase initialization for
  extension modules (PEP 489). Patch by Petr Viktorin.

- bpo-24351: Clarify what is meant by "identifier" in the context of
  string.Template instances.


- bpo-24432: Update Windows builds and OS X 10.5 installer to use OpenSSL

What's New in Python 3.5.0 beta 2?

*Release date: 2015-05-31*

Core and Builtins

- bpo-24284: The startswith and endswith methods of the str class no longer
  return True when finding the empty string and the indexes are completely
  out of range.

- bpo-24115: Update uses of PyObject_IsTrue(), PyObject_Not(),
  PyObject_IsInstance(), PyObject_RichCompareBool() and _PyDict_Contains()
  to check for and handle errors correctly.

- bpo-24328: Fix importing one character extension modules.

- bpo-11205: In dictionary displays, evaluate the key before the value.

- bpo-24285: Fixed regression that prevented importing extension modules
  from inside packages. Patch by Petr Viktorin.


- bpo-23247: Fix a crash in the StreamWriter.reset() of CJK codecs.

- bpo-24270: Add math.isclose() and cmath.isclose() functions as per PEP
  485. Contributed by Chris Barker and Tal Einat.

- bpo-5633: Fixed timeit when the statement is a string and the setup is

- bpo-24326: Fixed audioop.ratecv() with non-default weightB argument.
  Original patch by David Moore.

- bpo-16991: Add a C implementation of OrderedDict.

- bpo-23934: Fix inspect.signature to fail correctly for builtin types
  lacking signature information.  Initial patch by James Powell.

What's New in Python 3.5.0 beta 1?

*Release date: 2015-05-24*

Core and Builtins

- bpo-24276: Fixed optimization of property descriptor getter.

- bpo-24268: PEP 489: Multi-phase extension module initialization. Patch by
  Petr Viktorin.

- bpo-23955: Add pyvenv.cfg option to suppress registry/environment lookup
  for generating sys.path on Windows.

- bpo-24257: Fixed system error in the comparison of faked

- bpo-22939: Fixed integer overflow in iterator object.  Patch by Clement

- bpo-23985: Fix a possible buffer overrun when deleting a slice from the
  front of a bytearray and then appending some other bytes data.

- bpo-24102: Fixed exception type checking in standard error handlers.

- bpo-15027: The UTF-32 encoder is now 3x to 7x faster.

- bpo-23290: Optimize set_merge() for cases where the target is empty.
  (Contributed by Serhiy Storchaka.)

- bpo-2292: PEP 448: Additional Unpacking Generalizations.

- bpo-24096: Make warnings.warn_explicit more robust against mutation of the
  warnings.filters list.

- bpo-23996: Avoid a crash when a delegated generator raises an unnormalized
  StopIteration exception.  Patch by Stefan Behnel.

- bpo-23910: Optimize property() getter calls.  Patch by Joe Jevnik.

- bpo-23911: Move path-based importlib bootstrap code to a separate frozen

- bpo-24192: Fix namespace package imports.

- bpo-24022: Fix tokenizer crash when processing undecodable source code.

- bpo-9951: Added a hex() method to bytes, bytearray, and memoryview.

- bpo-22906: PEP 479: Change StopIteration handling inside generators.

- bpo-24017: PEP 492: Coroutines with async and await syntax.


- bpo-14373: Added C implementation of functools.lru_cache().  Based on
  patches by Matt Joiner and Alexey Kachayev.

- bpo-24230: The tempfile module now accepts bytes for prefix, suffix and
  dir parameters and returns bytes in such situations (matching the os
  module APIs).

- bpo-22189: collections.UserString now supports __getnewargs__(),
  __rmod__(), casefold(), format_map(), isprintable(), and maketrans().
  Patch by Joe Jevnik.

- bpo-24244: Prevents termination when an invalid format string is
  encountered on Windows in strftime.

- bpo-23973: PEP 484: Add the typing module.

- bpo-23086: The abstract base class added
  *start* and *stop* parameters to the index() mixin. Patch by Devin

- bpo-20035: Replaced the ``tkinter._fix`` module used for setting up the
  Tcl/Tk environment on Windows with a private function in the ``_tkinter``
  module that makes no permanent changes to the environment.

- bpo-24257: Fixed segmentation fault in sqlite3.Row constructor with faked
  cursor type.

- bpo-15836: assertRaises(), assertRaisesRegex(), assertWarns() and
  assertWarnsRegex() assertments now check the type of the first argument to
  prevent possible user error.  Based on patch by Daniel Wagner-Hall.

- bpo-9858: Add missing method stubs to _io.RawIOBase.  Patch by Laura

- bpo-22955: attrgetter, itemgetter and methodcaller objects in the operator
  module now support pickling.  Added readable and evaluable repr for these
  objects. Based on patch by Josh Rosenberg.

- bpo-22107: tempfile.gettempdir() and tempfile.mkdtemp() now try again when
  a directory with the chosen name already exists on Windows as well as on
  Unix. tempfile.mkstemp() now fails early if parent directory is not valid
  (not exists or is a file) on Windows.

- bpo-23780: Improved error message in os.path.join() with single argument.

- bpo-6598: Increased time precision and random number range in
  email.utils.make_msgid() to strengthen the uniqueness of the message ID.

- bpo-24091: Fixed various crashes in corner cases in C implementation of

- bpo-21931: msilib.FCICreate() now raises TypeError in the case of a bad
  argument instead of a ValueError with a bogus FCI error number. Patch by
  Jeffrey Armstrong.

- bpo-13866: *quote_via* argument added to urllib.parse.urlencode.

- bpo-20098: New mangle_from policy option for email, default True for
  compat32, but False for all other policies.

- bpo-24211: The email library now supports RFC 6532: it can generate
  headers using utf-8 instead of encoded words.

- bpo-16314: Added support for the LZMA compression in distutils.

- bpo-21804: poplib now supports RFC 6856 (UTF8).

- bpo-18682: Optimized pprint functions for builtin scalar types.

- bpo-22027: smtplib now supports RFC 6531 (SMTPUTF8).

- bpo-23488: Random generator objects now consume 2x less memory on 64-bit.

- bpo-1322: platform.dist() and platform.linux_distribution() functions are
  now deprecated.  Initial patch by Vajrasky Kok.

- bpo-22486: Added the math.gcd() function.  The fractions.gcd() function
  now is deprecated.  Based on patch by Mark Dickinson.

- bpo-24064: Property() docstrings are now writeable. (Patch by Berker

- bpo-22681: Added support for the koi8_t encoding.

- bpo-22682: Added support for the kz1048 encoding.

- bpo-23796: peek and read1 methods of BufferedReader now raise ValueError
  if they called on a closed object. Patch by John Hergenroeder.

- bpo-21795: smtpd now supports the 8BITMIME extension whenever the new
  *decode_data* constructor argument is set to False.

- bpo-24155: optimize heapq.heapify() for better cache performance when
  heapifying large lists.

- bpo-21800: imaplib now supports RFC 5161 (enable), RFC 6855
  (utf8/internationalized email) and automatically encodes non-ASCII
  usernames and passwords to UTF8.

- bpo-20274: When calling a _sqlite.Connection, it now complains if passed
  any keyword arguments.  Previously it silently ignored them.

- bpo-20274: Remove ignored and erroneous "kwargs" parameters from three
  METH_VARARGS methods on _sqlite.Connection.

- bpo-24134: assertRaises(), assertRaisesRegex(), assertWarns() and
  assertWarnsRegex() checks now emits a deprecation warning when callable is
  None or keyword arguments except msg is passed in the context manager

- bpo-24018: Add a abstract base class.
  Contributed by Stefan Behnel.

- bpo-23880: Tkinter's getint() and getdouble() now support Tcl_Obj.
  Tkinter's getdouble() now supports any numbers (in particular int).

- bpo-22619: Added negative limit support in the traceback module. Based on
  patch by Dmitry Kazakov.

- bpo-24094: Fix possible crash in json.encode with poorly behaved dict

- bpo-9246: On POSIX, os.getcwd() now supports paths longer than 1025 bytes.
  Patch written by William Orr.

- bpo-17445: add difflib.diff_bytes() to support comparison of byte strings
  (fixes a regression from Python 2).

- bpo-23917: Fall back to sequential compilation when ProcessPoolExecutor
  doesn't exist. Patch by Claudiu Popa.

- bpo-23008: Fixed resolving attributes with boolean value is False in

- Fix asyncio issue 235: LifoQueue and PriorityQueue's put didn't increment
  unfinished tasks (this bug was introduced when JoinableQueue was merged
  with Queue).

- bpo-23908: os functions now reject paths with embedded null character on
  Windows instead of silently truncating them.

- bpo-23728: binascii.crc_hqx() could return an integer outside of the range
  0-0xffff for empty data.

- bpo-23887: urllib.error.HTTPError now has a proper repr() representation.
  Patch by Berker Peksag.

- asyncio: New event loop APIs: set_task_factory() and get_task_factory().

- asyncio: async() function is deprecated in favour of ensure_future().

- bpo-24178: asyncio.Lock, Condition, Semaphore, and BoundedSemaphore
  support new 'async with' syntax.  Contributed by Yury Selivanov.

- bpo-24179: Support 'async for' for asyncio.StreamReader. Contributed by
  Yury Selivanov.

- bpo-24184: Add AsyncIterator and AsyncIterable ABCs to
  Contributed by Yury Selivanov.

- bpo-22547: Implement informative __repr__ for inspect.BoundArguments.
  Contributed by Yury Selivanov.

- bpo-24190: Implement inspect.BoundArgument.apply_defaults() method.
  Contributed by Yury Selivanov.

- bpo-20691: Add 'follow_wrapped' argument to
  inspect.Signature.from_callable() and inspect.signature(). Contributed by
  Yury Selivanov.

- bpo-24248: Deprecate inspect.Signature.from_function() and

- bpo-23898: Fix inspect.classify_class_attrs() to support attributes with
  overloaded __eq__ and __bool__.  Patch by Mike Bayer.

- bpo-24298: Fix inspect.signature() to correctly unwrap wrappers around
  bound methods.


- bpo-23184: remove unused names and imports in idlelib. Initial patch by Al


- bpo-21520: test_zipfile no longer fails if the word 'bad' appears anywhere
  in the name of the current directory.

- bpo-9517: Move script_helper into the support package. Patch by Christie


- bpo-22155: Add File Handlers subsection with createfilehandler to tkinter
  doc.  Remove obsolete example from FAQ.  Patch by Martin Panter.

- bpo-24029: Document the name binding behavior for submodule imports.

- bpo-24077: Fix typo in man page for -I command option: -s, not -S


- bpo-24000: Improved Argument Clinic's mapping of converters to legacy
  "format units". Updated the documentation to match.

- bpo-24001: Argument Clinic converters now use accept={type} instead of
  types={'type'} to specify the types the converter accepts.

- bpo-23330: h2py now supports arbitrary filenames in #include.

- bpo-24031: make patchcheck now supports git checkouts, too.

What's New in Python 3.5.0 alpha 4?

*Release date: 2015-04-19*

Core and Builtins

- bpo-22980: Under Linux, GNU/KFreeBSD and the Hurd, C extensions now
  include the architecture triplet in the extension name, to make it easy to
  test builds for different ABIs in the same working tree.  Under OS X, the
  extension name now includes PEP 3149-style information.

- bpo-22631: Added Linux-specific socket constant CAN_RAW_FD_FRAMES. Patch
  courtesy of Joe Jevnik.

- bpo-23731: Implement PEP 488: removal of .pyo files.

- bpo-23726: Don't enable GC for user subclasses of non-GC types that don't
  add any new fields.  Patch by Eugene Toder.

- bpo-23309: Avoid a deadlock at shutdown if a daemon thread is aborted
  while it is holding a lock to a buffered I/O object, and the main thread
  tries to use the same I/O object (typically stdout or stderr).  A fatal
  error is emitted instead.

- bpo-22977: Fixed formatting Windows error messages on Wine. Patch by
  Martin Panter.

- bpo-23466: %c, %o, %x, and %X in bytes formatting now raise TypeError on
  non-integer input.

- bpo-24044: Fix possible null pointer dereference in list.sort in out of
  memory conditions.

- bpo-21354: PyCFunction_New function is exposed by python DLL again.


- bpo-23840: now closes the temporary binary file on error
  to fix a resource warning.

- bpo-16914: new debuglevel 2 in smtplib adds timestamps to debug output.

- bpo-7159: urllib.request now supports sending auth credentials
  automatically after the first 401.  This enhancement is a superset of the
  enhancement from issue #19494 and supersedes that change.

- bpo-23703: Fix a regression in urljoin() introduced in 901e4e52b20a. Patch
  by Demian Brecht.

- bpo-4254: Adds _curses.update_lines_cols().  Patch by Arnon Yaari

- bpo-19933: Provide default argument for ndigits in round. Patch by
  Vajrasky Kok.

- bpo-23193: Add a numeric_owner parameter to tarfile.TarFile.extract and
  tarfile.TarFile.extractall. Patch by Michael Vogt and Eric Smith.

- bpo-23342: Add a function than returns a CalledProcess
  instance for a more consistent API than the existing call* functions.

- bpo-21217: inspect.getsourcelines() now tries to compute the start and end
  lines from the code object, fixing an issue when a lambda function is used
  as decorator argument. Patch by Thomas Ballinger and Allison Kaptur.

- bpo-24521: Fix possible integer overflows in the pickle module.

- bpo-22931: Allow '[' and ']' in cookie values.

- The keywords attribute of functools.partial is now always a dictionary.

- bpo-23811: Add missing newline to the PyCompileError error message. Patch
  by Alex Shkop.

- bpo-21116: Avoid blowing memory when allocating a multiprocessing shared
  array that's larger than 50% of the available RAM.  Patch by Médéric

- bpo-22982: Improve BOM handling when seeking to multiple positions of a
  writable text file.

- bpo-23464: Removed deprecated asyncio JoinableQueue.

- bpo-23529: Limit the size of decompressed data when reading from GzipFile,
  BZ2File or LZMAFile.  This defeats denial of service attacks using
  compressed bombs (i.e. compressed payloads which decompress to a huge
  size).  Patch by Martin Panter and Nikolaus Rath.

- bpo-21859: Added Python implementation of io.FileIO.

- bpo-23865: close() methods in multiple modules now are idempotent and more
  robust at shutdown. If they need to release multiple resources, all are
  released even if errors occur.

- bpo-23400: Raise same exception on both Python 2 and 3 if sem_open is not
  available. Patch by Davin Potts.

- bpo-10838: The subprocess now module includes SubprocessError and
  TimeoutError in its list of exported names for the users wild enough to
  use ``from subprocess import *``.

- bpo-23411: Added DefragResult, ParseResult, SplitResult,
  DefragResultBytes, ParseResultBytes, and SplitResultBytes to
  urllib.parse.__all__. Patch by Martin Panter.

- bpo-23881: urllib.request.ftpwrapper constructor now closes the socket if
  the FTP connection failed to fix a ResourceWarning.

- bpo-23853: :meth:`socket.socket.sendall` does no more reset the socket
  timeout each time data is sent successfully. The socket timeout is now the
  maximum total duration to send all data.

- bpo-22721: An order of multiline pprint output of set or dict containing
  orderable and non-orderable elements no longer depends on iteration order
  of set or dict.

- bpo-15133: _tkinter.tkapp.getboolean() now supports Tcl_Obj and always
  returns bool. tkinter.BooleanVar now validates input values (accepted
  bool, int, str, and Tcl_Obj).  tkinter.BooleanVar.get() now always returns

- bpo-10590: xml.sax.parseString() now supports string argument.

- bpo-23338: Fixed formatting ctypes error messages on Cygwin. Patch by
  Makoto Kato.

- bpo-15582: inspect.getdoc() now follows inheritance chains.

- bpo-2175: SAX parsers now support a character stream of InputSource

- bpo-16840: Tkinter now supports 64-bit integers added in Tcl 8.4 and
  arbitrary precision integers added in Tcl 8.5.

- bpo-23834: Fix socket.sendto(), use the C Py_ssize_t type to store the
  result of sendto() instead of the C int type.

- bpo-23618: :meth:`socket.socket.connect` now waits until the connection
  completes instead of raising :exc:`InterruptedError` if the connection is
  interrupted by signals, signal handlers don't raise an exception and the
  socket is blocking or has a timeout. :meth:`socket.socket.connect` still
  raise :exc:`InterruptedError` for non-blocking sockets.

- bpo-21526: Tkinter now supports new boolean type in Tcl 8.5.

- bpo-23836: Fix the faulthandler module to handle reentrant calls to its
  signal handlers.

- bpo-23838: linecache now clears the cache and returns an empty result on

- bpo-10395: Added os.path.commonpath(). Implemented in posixpath and
  ntpath. Based on patch by Rafik Draoui.

- bpo-23611: Serializing more "lookupable" objects (such as unbound methods
  or nested classes) now are supported with pickle protocols < 4.

- bpo-13583: sqlite3.Row now supports slice indexing.

- bpo-18473: Fixed 2to3 and 3to2 compatible pickle mappings.  Fixed
  ambigious reverse mappings.  Added many new mappings.  Import mapping is
  no longer applied to modules already mapped with full name mapping.

- bpo-23485: is now retried automatically with the
  recomputed timeout when interrupted by a signal, except if the signal
  handler raises an exception. This change is part of the PEP 475.

- bpo-23752: When built from an existing file descriptor, io.FileIO() now
  only calls fstat() once. Before fstat() was called twice, which was not

- bpo-23704: collections.deque() objects now support __add__, __mul__, and

- bpo-23171: csv.Writer.writerow() now supports arbitrary iterables.

- bpo-23745: The new email header parser now handles duplicate MIME
  parameter names without error, similar to how get_param behaves.

- bpo-22117: Fix os.utime(), it now rounds the timestamp towards minus
  infinity (-inf) instead of rounding towards zero.

- bpo-23310: Fix MagicMock's initializer to work with __methods__, just like
  configure_mock().  Patch by Kasia Jachim.


- bpo-23817: FreeBSD now uses "1.0" in the SOVERSION as other operating
  systems, instead of just "1".

- bpo-23501: Argument Clinic now generates code into separate files by


- bpo-23799: Added for running and cleaning up
  multiple threads.

- bpo-22390: test.regrtest now emits a warning if temporary files or
  directories are left after running a test.


- bpo-18128: pygettext now uses standard +NNNN format in the POT-Creation-
  Date header.

- bpo-23935: Argument Clinic's understanding of format units accepting
  bytes, bytearrays, and buffers is now consistent with both the
  documentation and the implementation.

- bpo-23944: Argument Clinic now wraps long impl prototypes at column 78.

- bpo-20586: Argument Clinic now ensures that functions without docstrings
  have signatures.

- bpo-23492: Argument Clinic now generates argument parsing code with
  PyArg_Parse instead of PyArg_ParseTuple if possible.

- bpo-23500: Argument Clinic is now smarter about generating the "#ifndef"
  (empty) definition of the methoddef macro: it's only generated once, even
  if Argument Clinic processes the same symbol multiple times, and it's
  emitted at the end of all processing rather than immediately after the
  first use.


- bpo-23998: PyImport_ReInitLock() now checks for lock allocation error

What's New in Python 3.5.0 alpha 3?

*Release date: 2015-03-28*

Core and Builtins

- bpo-23573: Increased performance of string search operations (str.find,
  str.index, str.count, the in operator, str.split, str.partition) with
  arguments of different kinds (UCS1, UCS2, UCS4).

- bpo-23753: Python doesn't support anymore platforms without stat() or
  fstat(), these functions are always required.

- bpo-23681: The -b option now affects comparisons of bytes with int.

- bpo-23632: Memoryviews now allow tuple indexing (including for multi-
  dimensional memoryviews).

- bpo-23192: Fixed generator lambdas.  Patch by Bruno Cauet.

- bpo-23629: Fix the default __sizeof__ implementation for variable-sized


- bpo-14260: The groupindex attribute of regular expression pattern object
  now is non- modifiable mapping.

- bpo-23792: Ignore KeyboardInterrupt when the pydoc pager is active. This
  mimics the behavior of the standard unix pagers, and prevents pipepager
  from shutting down while the pager itself is still running.

- bpo-23775: pprint() of OrderedDict now outputs the same representation as

- bpo-23765: Removed IsBadStringPtr calls in ctypes

- bpo-22364: Improved some re error messages using regex for hints.

- bpo-23742: ntpath.expandvars() no longer loses unbalanced single quotes.

- bpo-21717: The function now supports 'x' (exclusive
  creation) mode.

- bpo-21802: The reader in BufferedRWPair now is closed even when closing
  writer failed in BufferedRWPair.close().

- bpo-23622: Unknown escapes in regular expressions that consist of ``'\'``
  and ASCII letter now raise a deprecation warning and will be forbidden in
  Python 3.6.

- bpo-23671: string.Template now allows specifying the "self" parameter as a
  keyword argument.  string.Formatter now allows specifying the "self" and
  the "format_string" parameters as keyword arguments.

- bpo-23502: The pprint module now supports mapping proxies.

- bpo-17530: pprint now wraps long bytes objects and bytearrays.

- bpo-22687: Fixed some corner cases in breaking words in tetxtwrap. Got rid
  of quadratic complexity in breaking long words.

- bpo-4727: The copy module now uses pickle protocol 4 (PEP 3154) and
  supports copying of instances of classes whose __new__ method takes
  keyword-only arguments.

- bpo-23491: Added a zipapp module to support creating executable zip file
  archives of Python code. Registered ".pyz" and ".pyzw" extensions on
  Windows for these archives (PEP 441).

- bpo-23657: Avoid explicit checks for str in zipapp, adding support for
  pathlib.Path objects as arguments.

- bpo-23688: Added support of arbitrary bytes-like objects and avoided
  unnecessary copying of memoryview in gzip.GzipFile.write(). Original patch
  by Wolfgang Maier.

- bpo-23252: Added support for writing ZIP files to unseekable streams.

- bpo-23647: Increase impalib's MAXLINE to accommodate modern mailbox sizes.

- bpo-23539: If body is None, http.client.HTTPConnection.request now sets
  Content-Length to 0 for PUT, POST, and PATCH headers to avoid 411 errors
  from some web servers.

- bpo-22351: The nntplib.NNTP constructor no longer leaves the connection
  and socket open until the garbage collector cleans them up.  Patch by
  Martin Panter.

- bpo-23704: collections.deque() objects now support methods for index(),
  insert(), and copy().  This allows deques to be registered as a
  MutableSequence and it improves their substitutability for lists.

- bpo-23715: :func:`signal.sigwaitinfo` and :func:`signal.sigtimedwait` are
  now retried when interrupted by a signal not in the *sigset* parameter, if
  the signal handler does not raise an exception. signal.sigtimedwait()
  recomputes the timeout with a monotonic clock when it is retried.

- bpo-23001: Few functions in modules mmap, ossaudiodev, socket, ssl, and
  codecs, that accepted only read-only bytes-like object now accept writable
  bytes-like object too.

- bpo-23646: If time.sleep() is interrupted by a signal, the sleep is now
  retried with the recomputed delay, except if the signal handler raises an
  exception (PEP 475).

- bpo-23136: _strptime now uniformly handles all days in week 0, including
  Dec 30 of previous year.  Based on patch by Jim Carroll.

- bpo-23700: Iterator of NamedTemporaryFile now keeps a reference to
  NamedTemporaryFile instance.  Patch by Bohuslav Kabrda.

- bpo-22903: The fake test case created by unittest.loader when it fails
  importing a test module is now picklable.

- bpo-22181: On Linux, os.urandom() now uses the new getrandom() syscall if
  available, syscall introduced in the Linux kernel 3.17. It is more
  reliable and more secure, because it avoids the need of a file descriptor
  and waits until the kernel has enough entropy.

- bpo-2211: Updated the implementation of the http.cookies.Morsel class.
  Setting attributes key, value and coded_value directly now is deprecated.
  update() and setdefault() now transform and check keys.  Comparing for
  equality now takes into account attributes key, value and coded_value.
  copy() now returns a Morsel, not a dict.  repr() now contains all
  attributes. Optimized checking keys and quoting values.  Added new tests.
  Original patch by Demian Brecht.

- bpo-18983: Allow selection of output units in timeit. Patch by Julian

- bpo-23631: Fix traceback.format_list when a traceback has been mutated.

- bpo-23568: Add rdivmod support to MagicMock() objects. Patch by Håkan

- bpo-2052: Add charset parameter to HtmlDiff.make_file().

- bpo-23668: Support os.truncate and os.ftruncate on Windows.

- bpo-23138: Fixed parsing cookies with absent keys or values in cookiejar.
  Patch by Demian Brecht.

- bpo-23051: multiprocessing.Pool methods imap() and imap_unordered() now
  handle exceptions raised by an iterator.  Patch by Alon Diamant and Davin

- bpo-23581: Add matmul support to MagicMock. Patch by Håkan Lövdahl.

- bpo-23566: enable(), register(), dump_traceback() and
  dump_traceback_later() functions of faulthandler now accept file
  descriptors. Patch by Wei Wu.

- bpo-22928: Disabled HTTP header injections in http.client. Original patch
  by Demian Brecht.

- bpo-23615: Modules bz2, tarfile and tokenize now can be reloaded with
  imp.reload(). Patch by Thomas Kluyver.

- bpo-23605: os.walk() now calls os.scandir() instead of os.listdir(). The
  usage of os.scandir() reduces the number of calls to os.stat(). Initial
  patch written by Ben Hoyt.


- bpo-23585: make patchcheck will ensure the interpreter is built.


- bpo-23583: Added tests for standard IO streams in IDLE.

- bpo-22289: Prevent test_urllib2net failures due to ftp connection timeout.


- bpo-22826: The result of open() in Tools/freeze/ is now better
  compatible with regular files (in particular it now supports the context
  management protocol).

What's New in Python 3.5.0 alpha 2?

*Release date: 2015-03-09*

Core and Builtins

- bpo-23571: PyObject_Call() and PyCFunction_Call() now raise a SystemError
  if a function returns a result and raises an exception. The SystemError is
  chained to the previous exception.


- bpo-22524: New os.scandir() function, part of the PEP 471: "os.scandir()
  function -- a better and faster directory iterator". Patch written by Ben

- bpo-23103: Reduced the memory consumption of IPv4Address and IPv6Address.

- bpo-21793: BaseHTTPRequestHandler again logs response code as numeric, not
  as stringified enum.  Patch by Demian Brecht.

- bpo-23476: In the ssl module, enable OpenSSL's X509_V_FLAG_TRUSTED_FIRST
  flag on certificate stores when it is available.

- bpo-23576: Avoid stalling in SSL reads when EOF has been reached in the
  SSL layer but the underlying connection hasn't been closed.

- bpo-23504: Added an __all__ to the types module.

- bpo-23563: Optimized utility functions in urllib.parse.

- bpo-7830: Flatten nested functools.partial.

- bpo-20204: Added the __module__ attribute to _tkinter classes.

- bpo-19980: Improved help() for non-recognized strings.  help('') now shows
  the help on str.  help('help') now shows the help on help(). Original
  patch by Mark Lawrence.

- bpo-23521: Corrected pure python implementation of timedelta division.

  Eliminated OverflowError from ``timedelta * float`` for some floats;
  Corrected rounding in timedlta true division.

- bpo-21619: Popen objects no longer leave a zombie after exit in the with
  statement if the pipe was broken.  Patch by Martin Panter.

- bpo-22936: Make it possible to show local variables in tracebacks for both
  the traceback module and unittest.

- bpo-15955: Add an option to limit the output size in bz2.decompress().
  Patch by Nikolaus Rath.

- bpo-6639: Module-level turtle functions no longer raise TclError after
  closing the window.

- bpo-814253: Group references and conditional group references now work in
  lookbehind assertions in regular expressions. (See also: bpo-9179)

- bpo-23215: Multibyte codecs with custom error handlers that ignores errors
  consumed too much memory and raised SystemError or MemoryError. Original
  patch by Aleksi Torhamo.

- bpo-5700: io.FileIO() called flush() after closing the file. flush() was
  not called in close() if closefd=False.

- bpo-23374: Fixed pydoc failure with non-ASCII files when stdout encoding
  differs from file system encoding (e.g. on Mac OS).

- bpo-23481: Remove RC4 from the SSL module's default cipher list.

- bpo-21548: Fix pydoc.synopsis() and pydoc.apropos() on modules with empty

- bpo-22885: Fixed arbitrary code execution vulnerability in the dbm.dumb
  module. Original patch by Claudiu Popa.

- bpo-23239: ssl.match_hostname() now supports matching of IP addresses.

- bpo-23146: Fix mishandling of absolute Windows paths with forward slashes
  in pathlib.

- bpo-23096: Pickle representation of floats with protocol 0 now is the same
  for both Python and C implementations.

- bpo-19105: pprint now more efficiently uses free space at the right.

- bpo-14910: Add allow_abbrev parameter to argparse.ArgumentParser. Patch by
  Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.

- bpo-21717: now supports 'x' (exclusive creation) mode.

- bpo-23344: marshal.dumps() is now 20-25% faster on average.

- bpo-20416: marshal.dumps() with protocols 3 and 4 is now 40-50% faster on

- bpo-23421: Fixed compression in tarfile CLI.  Patch by wdv4758h.

- bpo-23367: Fix possible overflows in the unicodedata module.

- bpo-23361: Fix possible overflow in Windows subprocess creation code.

- logging.handlers.QueueListener now takes a respect_handler_level keyword
  argument which, if set to True, will pass messages to handlers taking
  handler levels into account.

- bpo-19705: turtledemo now has a visual sorting algorithm demo.  Original
  patch from Jason Yeo.

- bpo-23801: Fix issue where cgi.FieldStorage did not always ignore the
  entire preamble to a multipart body.


- bpo-23445: pydebug builds now use "gcc -Og" where possible, to make the
  resulting executable faster.

- bpo-23686: Update OS X 10.5 installer build to use OpenSSL 1.0.2a.


- bpo-20204: Deprecation warning is now raised for builtin types without the
  __module__ attribute.


- bpo-23465: Implement PEP 486 - Make the Python Launcher aware of virtual
  environments. Patch by Paul Moore.

- bpo-23437: Make user scripts directory versioned on Windows. Patch by Paul

What's New in Python 3.5.0 alpha 1?

*Release date: 2015-02-08*

Core and Builtins

- bpo-23285: PEP 475 - EINTR handling.

- bpo-22735: Fix many edge cases (including crashes) involving custom mro()

- bpo-22896: Avoid using PyObject_AsCharBuffer(), PyObject_AsReadBuffer()
  and PyObject_AsWriteBuffer().

- bpo-21295: Revert some changes (issue #16795) to AST line numbers and
  column offsets that constituted a regression.

- bpo-22986: Allow changing an object's __class__ between a dynamic type and
  static type in some cases.

- bpo-15859: PyUnicode_EncodeFSDefault(), PyUnicode_EncodeMBCS() and
  PyUnicode_EncodeCodePage() now raise an exception if the object is not a
  Unicode object. For PyUnicode_EncodeFSDefault(), it was already the case
  on platforms other than Windows. Patch written by Campbell Barton.

- bpo-21408: The default __ne__() now returns NotImplemented if __eq__()
  returned NotImplemented.  Original patch by Martin Panter.

- bpo-23321: Fixed a crash in str.decode() when error handler returned
  replacment string longer than mailformed input data.

- bpo-22286: The "backslashreplace" error handlers now works with decoding
  and translating.

- bpo-23253: Delay-load ShellExecute[AW] in os.startfile for reduced startup
  overhead on Windows.

- bpo-22038: pyatomic.h now uses stdatomic.h or GCC built-in functions for
  atomic memory access if available. Patch written by Vitor de Lima and
  Gustavo Temple.

- bpo-20284: %-interpolation (aka printf) formatting added for bytes and

- bpo-23048: Fix jumping out of an infinite while loop in the pdb.

- bpo-20335: bytes constructor now raises TypeError when encoding or errors
  is specified with non-string argument.  Based on patch by Renaud Blanch.

- bpo-22834: If the current working directory ends up being set to a non-
  existent directory then import will no longer raise FileNotFoundError.

- bpo-22869: Move the interpreter startup & shutdown code to a new dedicated
  pylifecycle.c module

- bpo-22847: Improve method cache efficiency.

- bpo-22335: Fix crash when trying to enlarge a bytearray to 0x7fffffff
  bytes on a 32-bit platform.

- bpo-22653: Fix an assertion failure in debug mode when doing a reentrant
  dict insertion in debug mode.

- bpo-22643: Fix integer overflow in Unicode case operations (upper, lower,
  title, swapcase, casefold).

- bpo-17636: Circular imports involving relative imports are now supported.

- bpo-22604: Fix assertion error in debug mode when dividing a complex
  number by (nan+0j).

- bpo-21052: Do not raise ImportWarning when sys.path_hooks or sys.meta_path
  are set to None.

- bpo-16518: Use 'bytes-like object required' in error messages that
  previously used the far more cryptic "'x' does not support the buffer

- bpo-22470: Fixed integer overflow issues in "backslashreplace",
  "xmlcharrefreplace", and "surrogatepass" error handlers.

- bpo-22540: speed up `PyObject_IsInstance` and `PyObject_IsSubclass` in the
  common case that the second argument has metaclass `type`.

- bpo-18711: Add a new `PyErr_FormatV` function, similar to `PyErr_Format`
  but accepting a `va_list` argument.

- bpo-22520: Fix overflow checking when generating the repr of a unicode

- bpo-22519: Fix overflow checking in PyBytes_Repr.

- bpo-22518: Fix integer overflow issues in latin-1 encoding.

- bpo-16324: _charset parameter of MIMEText now also accepts
  email.charset.Charset instances. Initial patch by Claude Paroz.

- bpo-1764286: Fix inspect.getsource() to support decorated functions. Patch
  by Claudiu Popa.

- bpo-18554: os.__all__ includes posix functions.

- bpo-21391: Use os.path.abspath in the shutil module.

- bpo-11471: avoid generating a JUMP_FORWARD instruction at the end of an
  if-block if there is no else-clause.  Original patch by Eugene Toder.

- bpo-22215: Now ValueError is raised instead of TypeError when str or bytes
  argument contains not permitted null character or byte.

- bpo-22258: Fix the internal function set_inheritable() on Illumos. This
  platform exposes the function ``ioctl(FIOCLEX)``, but calling it fails
  with errno is ENOTTY: "Inappropriate ioctl for device". set_inheritable()
  now falls back to the slower ``fcntl()`` (``F_GETFD`` and then

- bpo-21389: Displaying the __qualname__ of the underlying function in the
  repr of a bound method.

- bpo-22206: Using pthread, PyThread_create_key() now sets errno to ENOMEM
  and returns -1 (error) on integer overflow.

- bpo-20184: Argument Clinic based signature introspection added for 30 of
  the builtin functions.

- bpo-22116: C functions and methods (of the 'builtin_function_or_method'
  type) can now be weakref'ed.  Patch by Wei Wu.

- bpo-22077: Improve index error messages for bytearrays, bytes, lists, and
  tuples by adding 'or slices'. Added ', not ' for bytearrays.
  Original patch by Claudiu Popa.

- bpo-20179: Apply Argument Clinic to bytes and bytearray. Patch by Tal

- bpo-22082: Clear interned strings in slotdefs.

- Upgrade Unicode database to Unicode 7.0.0.

- bpo-21897: Fix a crash with the f_locals attribute with closure variables
  when frame.clear() has been called.

- bpo-21205: Add a new ``__qualname__`` attribute to generator, the
  qualified name, and use it in the representation of a generator
  (``repr(gen)``). The default name of the generator (``__name__``
  attribute) is now get from the function instead of the code. Use
  ``gen.gi_code.co_name`` to get the name of the code.

- bpo-21669: With the aid of heuristics in SyntaxError.__init__, the parser
  now attempts to generate more meaningful (or at least more search engine
  friendly) error messages when "exec" and "print" are used as statements.

- bpo-21642: In the conditional if-else expression, allow an integer written
  with no space between itself and the ``else`` keyword (e.g. ``True if
  42else False``) to be valid syntax.

- bpo-21523: Fix over-pessimistic computation of the stack effect of some
  opcodes in the compiler.  This also fixes a quadratic compilation time
  issue noticeable when compiling code with a large number of "and" and "or"

- bpo-21418: Fix a crash in the builtin function super() when called without
  argument and without current frame (ex: embedded Python).

- bpo-21425: Fix flushing of standard streams in the interactive

- bpo-21435: In rare cases, when running finalizers on objects in cyclic
  trash a bad pointer dereference could occur due to a subtle flaw in
  internal iteration logic.

- bpo-21377: PyBytes_Concat() now tries to concatenate in-place when the
  first argument has a reference count of 1.  Patch by Nikolaus Rath.

- bpo-20355: -W command line options now have higher priority than the
  PYTHONWARNINGS environment variable.  Patch by Arfrever.

- bpo-21274: Define PATH_MAX for GNU/Hurd in Python/pythonrun.c.

- bpo-20904: Support setting FPU precision on m68k.

- bpo-21209: Fix sending tuples to custom generator objects with the yield
  from syntax.

- bpo-21193: pow(a, b, c) now raises ValueError rather than TypeError when b
  is negative. Patch by Josh Rosenberg.

- bpo-21176: PEP 465: Add the '@' operator for matrix multiplication.

- bpo-21134: Fix segfault when str is called on an uninitialized
  UnicodeEncodeError, UnicodeDecodeError, or UnicodeTranslateError object.

- bpo-19537: Fix PyUnicode_DATA() alignment under m68k.  Patch by Andreas

- bpo-20929: Add a type cast to avoid shifting a negative number.

- bpo-20731: Properly position in source code files even if they are opened
  in text mode. Patch by Serhiy Storchaka.

- bpo-20637: Key-sharing now also works for instance dictionaries of
  subclasses.  Patch by Peter Ingebretson.

- bpo-8297: Attributes missing from modules now include the module name in
  the error text.  Original patch by ysj.ray.

- bpo-19995: %c, %o, %x, and %X now raise TypeError on non-integer input.

- bpo-19655: The ASDL parser - used by the build process to generate code
  for managing the Python AST in C - was rewritten. The new parser is self
  contained and does not require to carry long the parser-generator
  library; was removed from the source base.

- bpo-12546: Allow ``\x00`` to be used as a fill character when using str,
  int, float, and complex __format__ methods.

- bpo-20480: Add ipaddress.reverse_pointer. Patch by Leon Weber.

- bpo-13598: Modify string.Formatter to support auto-numbering of
  replacement fields. It now matches the behavior of str.format() in this
  regard. Patches by Phil Elson and Ramchandra Apte.

- bpo-8931: Make alternate formatting ('#') for type 'c' raise an exception.
  In versions prior to 3.5, '#' with 'c' had no effect. Now specifying it is
  an error. Patch by Torsten Landschoff.

- bpo-23165: Perform overflow checks before allocating memory in the
  _Py_char2wchar function.


- bpo-23399: pyvenv creates relative symlinks where possible.

- bpo-20289: cgi.FieldStorage() now supports the context management

- bpo-13128: Print response headers for CONNECT requests when debuglevel >
  0. Patch by Demian Brecht.

- bpo-15381: Optimized io.BytesIO to make less allocations and copyings.

- bpo-22818: Splitting on a pattern that could match an empty string now
  raises a warning.  Patterns that can only match empty strings are now

- bpo-23099: Closing io.BytesIO with exported buffer is rejected now to
  prevent corrupting exported buffer.

- bpo-23326: Removed __ne__ implementations.  Since fixing default __ne__
  implementation in issue #21408 they are redundant.

- bpo-23363: Fix possible overflow in itertools.permutations.

- bpo-23364: Fix possible overflow in itertools.product.

- bpo-23366: Fixed possible integer overflow in itertools.combinations.

- bpo-23369: Fixed possible integer overflow in

- bpo-23353: Fix the exception handling of generators in
  PyEval_EvalFrameEx(). At entry, save or swap the exception state even if
  PyEval_EvalFrameEx() is called with throwflag=0. At exit, the exception
  state is now always restored or swapped, not only if why is WHY_YIELD or
  WHY_RETURN. Patch co-written with Antoine Pitrou.

- bpo-14099: Restored support of writing ZIP files to tellable but non-
  seekable streams.

- bpo-14099: Writing to ZipFile and reading multiple ZipExtFiles is
  threadsafe now.

- bpo-19361: JSON decoder now raises JSONDecodeError instead of ValueError.

- bpo-18518: timeit now rejects statements which can't be compiled outside a
  function or a loop (e.g. "return" or "break").

- bpo-23094: Fixed readline with frames in Python implementation of pickle.

- bpo-23268: Fixed bugs in the comparison of ipaddress classes.

- bpo-21408: Removed incorrect implementations of __ne__() which didn't
  returned NotImplemented if __eq__() returned NotImplemented.  The default
  __ne__() now works correctly.

- bpo-19996: :class:`email.feedparser.FeedParser` now handles (malformed)
  headers with no key rather than assuming the body has started.

- bpo-20188: Support Application-Layer Protocol Negotiation (ALPN) in the
  ssl module.

- bpo-23133: Pickling of ipaddress objects now produces more compact and
  portable representation.

- bpo-23248: Update ssl error codes from latest OpenSSL git master.

- bpo-23266: Much faster implementation of ipaddress.collapse_addresses()
  when there are many non-consecutive addresses.

- bpo-23098: 64-bit dev_t is now supported in the os module.

- bpo-21817: When an exception is raised in a task submitted to a
  ProcessPoolExecutor, the remote traceback is now displayed in the parent
  process.  Patch by Claudiu Popa.

- bpo-15955: Add an option to limit output size when decompressing LZMA
  data.  Patch by Nikolaus Rath and Martin Panter.

- bpo-23250: In the http.cookies module, capitalize "HttpOnly" and "Secure"
  as they are written in the standard.

- bpo-23063: In the disutils' check command, fix parsing of reST with code
  or code-block directives.

- bpo-23209: selectors.BaseSelector.get_key() now raises a RuntimeError if
  the selector is closed. And selectors.BaseSelector.close() now clears its
  internal reference to the selector mapping to break a reference cycle.
  Initial patch written by Martin Richard. (See also: bpo-23225)

- bpo-17911: Provide a way to seed the linecache for a PEP-302 module
  without actually loading the code.

- bpo-17911: Provide a new object API for traceback, including the ability
  to not lookup lines at all until the traceback is actually rendered,
  without any trace of the original objects being kept alive.

- bpo-19777: Provide a home() classmethod on Path objects.  Contributed by
  Victor Salgado and Mayank Tripathi.

- bpo-23206: Make ``json.dumps(..., ensure_ascii=False)`` as fast as the
  default case of ``ensure_ascii=True``.  Patch by Naoki Inada.

- bpo-23185: Add math.inf and math.nan constants.

- bpo-23186: Add ssl.SSLObject.shared_ciphers() and
  ssl.SSLSocket.shared_ciphers() to fetch the client's list ciphers sent at

- bpo-23143: Remove compatibility with OpenSSLs older than 0.9.8.

- bpo-23132: Improve performance and introspection support of comparison
  methods created by functool.total_ordering.

- bpo-19776: Add an expanduser() method on Path objects.

- bpo-23112: Fix SimpleHTTPServer to correctly carry the query string and
  fragment when it redirects to add a trailing slash.

- bpo-21793: Added http.HTTPStatus enums (i.e. HTTPStatus.OK,
  HTTPStatus.NOT_FOUND). Patch by Demian Brecht.

- bpo-23093: In the io, module allow more operations to work on detached

- bpo-23111: In the ftplib, make ssl.PROTOCOL_SSLv23 the default protocol

- bpo-22585: On OpenBSD 5.6 and newer, os.urandom() now calls getentropy(),
  instead of reading /dev/urandom, to get pseudo-random bytes.

- bpo-19104: pprint now produces evaluable output for wrapped strings.

- bpo-23071: Added missing names to codecs.__all__.  Patch by Martin Panter.

- bpo-22783: Pickling now uses the NEWOBJ opcode instead of the NEWOBJ_EX
  opcode if possible.

- bpo-15513: Added a __sizeof__ implementation for pickle classes.

- bpo-19858: pickletools.optimize() now aware of the MEMOIZE opcode, can
  produce more compact result and no longer produces invalid output if input
  data contains MEMOIZE opcodes together with PUT or BINPUT opcodes.

- bpo-22095: Fixed HTTPConnection.set_tunnel with default port.  The port
  value in the host header was set to "None".  Patch by Demian Brecht.

- bpo-23016: A warning no longer produces an AttributeError when the program
  is run with pythonw.exe.

- bpo-21775: shutil.copytree(): fix crash when copying to VFAT. An exception
  handler assumed that OSError objects always have a 'winerror' attribute.
  That is not the case, so the exception handler itself raised
  AttributeError when run on Linux (and, presumably, any other non-Windows
  OS). Patch by Greg Ward.

- bpo-1218234: Fix inspect.getsource() to load updated source of reloaded
  module. Initial patch by Berker Peksag.

- bpo-21740: Support wrapped callables in doctest. Patch by Claudiu Popa.

- bpo-23009: Make sure works when no FD is

- bpo-22959: In the constructor of http.client.HTTPSConnection, prefer the
  context's check_hostname attribute over the *check_hostname* parameter.

- bpo-22696: Add function :func:`sys.is_finalizing` to know about
  interpreter shutdown.

- bpo-16043: Add a default limit for the amount of data
  xmlrpclib.gzip_decode will return. This resolves CVE-2013-1753.

- bpo-14099: no longer reopen the underlying file.  Objects
  returned by can now operate independently of the ZipFile
  even if the ZipFile was created by passing in a file-like object as the
  first argument to the constructor.

- bpo-22966: Fix __pycache__ pyc file name clobber when pyc_compile is asked
  to compile a source file containing multiple dots in the source file name.

- bpo-21971: Update turtledemo doc and add module to the index.

- bpo-21032: Fixed socket leak if HTTPConnection.getresponse() fails.
  Original patch by Martin Panter.

- bpo-22407: Deprecated the use of re.LOCALE flag with str patterns or
  re.ASCII. It was newer worked.

- bpo-22902: The "ip" command is now used on Linux to determine MAC address
  in uuid.getnode().  Pach by Bruno Cauet.

- bpo-22960: Add a context argument to xmlrpclib.ServerProxy constructor.

- bpo-22389: Add contextlib.redirect_stderr().

- bpo-21356: Make ssl.RAND_egd() optional to support LibreSSL. The
  availability of the function is checked during the compilation. Patch
  written by Bernard Spil.

- bpo-22915: SAX parser now supports files opened with file descriptor or
  bytes path.

- bpo-22609: Constructors and update methods of mapping classes in the
  collections module now accept the self keyword argument.

- bpo-22940: Add readline.append_history_file.

- bpo-19676: Added the "namereplace" error handler.

- bpo-22788: Add *context* parameter to logging.handlers.HTTPHandler.

- bpo-22921: Allow SSLContext to take the *hostname* parameter even if
  OpenSSL doesn't support SNI.

- bpo-22894: TestCase.subTest() would cause the test suite to be stopped
  when in failfast mode, even in the absence of failures.

- bpo-22796: HTTP cookie parsing is now stricter, in order to protect
  against potential injection attacks.

- bpo-22370: Windows detection in pathlib is now more robust.

- bpo-22841: Reject coroutines in asyncio add_signal_handler(). Patch by

- bpo-19494: Added urllib.request.HTTPBasicPriorAuthHandler. Patch by Matej

- bpo-22578: Added attributes to the re.error class.

- bpo-22849: Fix possible double free in the io.TextIOWrapper constructor.

- bpo-12728: Different Unicode characters having the same uppercase but
  different lowercase are now matched in case-insensitive regular

- bpo-22821: Fixed fcntl() with integer argument on 64-bit big-endian

- bpo-21650: Add an `--sort-keys` option to json.tool CLI.

- bpo-22824: Updated reprlib output format for sets to use set literals.
  Patch contributed by Berker Peksag.

- bpo-22824: Updated reprlib output format for arrays to display empty
  arrays without an unnecessary empty list.  Suggested by Serhiy Storchaka.

- bpo-22406: Fixed the uu_codec codec incorrectly ported to 3.x. Based on
  patch by Martin Panter.

- bpo-17293: uuid.getnode() now determines MAC address on AIX using netstat.
  Based on patch by Aivars Kalvāns.

- bpo-22769: Fixed ttk.Treeview.tag_has() when called without arguments.

- bpo-22417: Verify certificates by default in httplib (PEP 476).

- bpo-22775: Fixed unpickling of http.cookies.SimpleCookie with protocol 2
  and above. Patch by Tim Graham.

- bpo-22776: Brought excluded code into the scope of a try block in

- bpo-22665: Add missing get_terminal_size and SameFileError to

- bpo-6623: Remove deprecated Netrc class in the ftplib module. Patch by
  Matt Chaput.

- bpo-17381: Fixed handling of case-insensitive ranges in regular

- bpo-22410: Module level functions in the re module now cache compiled
  locale-dependent regular expressions taking into account the locale.

- bpo-22759: Query methods on pathlib.Path() (exists(), is_dir(), etc.) now
  return False when the underlying stat call raises NotADirectoryError.

- bpo-8876: distutils now falls back to copying files when hard linking
  doesn't work. This allows use with special filesystems such as VirtualBox
  shared folders.

- bpo-22217: Implemented reprs of classes in the zipfile module.

- bpo-22457: Honour load_tests in the start_dir of discovery.

- bpo-18216: gettext now raises an error when a .mo file has an unsupported
  major version number.  Patch by Aaron Hill.

- bpo-13918: Provide a locale.delocalize() function which can remove locale-
  specific number formatting from a string representing a number, without
  then converting it to a specific type.  Patch by Cédric Krier.

- bpo-22676: Make the pickling of global objects which don't have a
  __module__ attribute less slow.

- bpo-18853: Fixed ResourceWarning in shlex.__nain__.

- bpo-9351: Defaults set with set_defaults on an argparse subparser are no
  longer ignored when also set on the parent parser.

- bpo-7559: unittest test loading ImportErrors are reported as import errors
  with their import exception rather than as attribute errors after the
  import has already failed.

- bpo-19746: Make it possible to examine the errors from unittest discovery
  without executing the test suite. The new `errors` attribute on TestLoader
  exposes these non-fatal errors encountered during discovery.

- bpo-21991: Make email.headerregistry's header 'params' attributes be read-
  only (MappingProxyType).  Previously the dictionary was modifiable but a
  new one was created on each access of the attribute.

- bpo-22638: SSLv3 is now disabled throughout the standard library. It can
  still be enabled by instantiating a SSLContext manually.

- bpo-22641: In asyncio, the default SSL context for client connections is
  now created using ssl.create_default_context(), for stronger security.

- bpo-17401: Include closefd in io.FileIO repr.

- bpo-21338: Add silent mode for compileall. quiet parameters of
  compile_{dir, file, path} functions now have a multilevel value. Also, -q
  option of the CLI now have a multilevel value. Patch by Thomas Kluyver.

- bpo-20152: Convert the array and cmath modules to Argument Clinic.

- bpo-18643: Add socket.socketpair() on Windows.

- bpo-22435: Fix a file descriptor leak when socketserver bind fails.

- bpo-13096: Fixed segfault in CTypes POINTER handling of large values.

- bpo-11694: Raise ConversionError in xdrlib as documented.  Patch by Filip
  Gruszczyński and Claudiu Popa.

- bpo-19380: Optimized parsing of regular expressions.

- bpo-1519638: Now unmatched groups are replaced with empty strings in
  re.sub() and re.subn().

- bpo-18615: sndhdr.what/whathdr now return a namedtuple.

- bpo-22462: Fix pyexpat's creation of a dummy frame to make it appear in
  exception tracebacks.

- bpo-21965: Add support for in-memory SSL to the ssl module.  Patch by
  Geert Jansen.

- bpo-21173: Fix len() on a WeakKeyDictionary when .clear() was called with
  an iterator alive.

- bpo-11866: Eliminated race condition in the computation of names for new

- bpo-21905: Avoid RuntimeError in pickle.whichmodule() when sys.modules is
  mutated while iterating.  Patch by Olivier Grisel.

- bpo-11271: now takes a *chunksize*
  argument to allow batching of tasks in child processes and improve
  performance of ProcessPoolExecutor.  Patch by Dan O'Reilly.

- bpo-21883: os.path.join() and os.path.relpath() now raise a TypeError with
  more helpful error message for unsupported or mismatched types of

- bpo-22219: The zipfile module CLI now adds entries for directories
  (including empty directories) in ZIP file.

- bpo-22449: In the ssl.SSLContext.load_default_certs, consult the
  environmental variables SSL_CERT_DIR and SSL_CERT_FILE on Windows.

- bpo-22508: The email.__version__ variable has been removed; the email code
  is no longer shipped separately from the stdlib, and __version__ hasn't
  been updated in several releases.

- bpo-20076: Added non derived UTF-8 aliases to locale aliases table.

- bpo-20079: Added locales supported in glibc 2.18 to locale alias table.

- bpo-20218: Added convenience methods read_text/write_text and read_bytes/
  write_bytes to pathlib.Path objects.

- bpo-22396: On 32-bit AIX platform, don't expose os.posix_fadvise() nor
  os.posix_fallocate() because their prototypes in system headers are wrong.

- bpo-22517: When an io.BufferedRWPair object is deallocated, clear its

- bpo-22437: Number of capturing groups in regular expression is no longer
  limited by 100.

- bpo-17442: InteractiveInterpreter now displays the full chained traceback
  in its showtraceback method, to match the built in interactive

- bpo-23392: Added tests for marshal C API that works with FILE*.

- bpo-10510: distutils register and upload methods now use HTML standards
  compliant CRLF line endings.

- bpo-9850: Fixed macpath.join() for empty first component.  Patch by Oleg

- bpo-5309: distutils' build and build_ext commands now accept a ``-j``
  option to enable parallel building of extension modules.

- bpo-22448: Improve canceled timer handles cleanup to prevent unbound
  memory usage. Patch by Joshua Moore-Oliva.

- bpo-22427: TemporaryDirectory no longer attempts to clean up twice when
  used in the with statement in generator.

- bpo-22362: Forbidden ambiguous octal escapes out of range 0-0o377 in
  regular expressions.

- bpo-20912: Now directories added to ZIP file have correct Unix and MS-DOS
  directory attributes.

- bpo-21866: ZipFile.close() no longer writes ZIP64 central directory
  records if allowZip64 is false.

- bpo-22278: Fix urljoin problem with relative urls, a regression observed
  after changes to issue22118 were submitted.

- bpo-22415: Fixed debugging output of the GROUPREF_EXISTS opcode in the re
  module. Removed trailing spaces in debugging output.

- bpo-22423: Unhandled exception in thread no longer causes unhandled
  AttributeError when sys.stderr is None.

- bpo-21332: Ensure that ``bufsize=1`` in subprocess.Popen() selects line
  buffering, rather than block buffering.  Patch by Akira Li.

- bpo-21091: Fix API bug: email.message.EmailMessage.is_attachment is now a

- bpo-21079: Fix email.message.EmailMessage.is_attachment to return the
  correct result when the header has parameters as well as a value.

- bpo-22247: Add NNTPError to nntplib.__all__.

- bpo-22366: urllib.request.urlopen will accept a context object
  (SSLContext) as an argument which will then be used for HTTPS connection.
  Patch by Alex Gaynor.

- bpo-4180: The warnings registries are now reset when the filters are

- bpo-22419: Limit the length of incoming HTTP request in wsgiref server to
  65536 bytes and send a 414 error code for higher lengths. Patch
  contributed by Devin Cook.

- Lax cookie parsing in http.cookies could be a security issue when combined
  with non-standard cookie handling in some Web browsers.  Reported by
  Sergey Bobrov.

- bpo-20537: logging methods now accept an exception instance as well as a
  Boolean value or exception tuple. Thanks to Yury Selivanov for the patch.

- bpo-22384: An exception in Tkinter callback no longer crashes the program
  when it is run with pythonw.exe.

- bpo-22168: Prevent turtle AttributeError with non-default Canvas on OS X.

- bpo-21147: sqlite3 now raises an exception if the request contains a null
  character instead of truncating it.  Based on patch by Victor Stinner.

- bpo-13968: The glob module now supports recursive search in subdirectories
  using the ``**`` pattern.

- bpo-21951: Fixed a crash in Tkinter on AIX when called Tcl command with
  empty string or tuple argument.

- bpo-21951: Tkinter now most likely raises MemoryError instead of crash if
  the memory allocation fails.

- bpo-22338: Fix a crash in the json module on memory allocation failure.

- bpo-12410: imaplib.IMAP4 now supports the context management protocol.
  Original patch by Tarek Ziadé.

- bpo-21270: We now override tuple methods in objects so that they
  can be used as normal call attributes.

- bpo-16662: load_tests() is now unconditionally run when it is present in a
  package's  TestLoader.loadTestsFromModule() still accepts
  use_load_tests, but it is deprecated and ignored.  A new keyword-only
  attribute `pattern` is added and documented.  Patch given by Robert
  Collins, tweaked by Barry Warsaw.

- bpo-22226: First letter no longer is stripped from the "status" key in the
  result of Treeview.heading().

- bpo-19524: Fixed resource leak in the HTTP connection when an invalid
  response is received.  Patch by Martin Panter.

- bpo-20421: Add a .version() method to SSL sockets exposing the actual
  protocol version in use.

- bpo-19546: configparser exceptions no longer expose implementation
  details. Chained KeyErrors are removed, which leads to cleaner tracebacks.
  Patch by Claudiu Popa.

- bpo-22051: turtledemo no longer reloads examples to re-run them.
  Initialization of variables and gui setup should be done in main(), which
  is called each time a demo is run, but not on import.

- bpo-21933: Turtledemo users can change the code font size with a menu
  selection or control(command) '-' or '+' or control-mousewheel. Original
  patch by Lita Cho.

- bpo-21597: The separator between the turtledemo text pane and the drawing
  canvas can now be grabbed and dragged with a mouse.  The code text pane
  can be widened to easily view or copy the full width of the text.  The
  canvas can be widened on small screens.  Original patches by Jan Kanis and
  Lita Cho.

- bpo-18132: Turtledemo buttons no longer disappear when the window is
  shrunk.  Original patches by Jan Kanis and Lita Cho.

- bpo-22043: time.monotonic() is now always available.
  ``threading.Lock.acquire()``, ``threading.RLock.acquire()`` and socket
  operations now use a monotonic clock, instead of the system clock, when a
  timeout is used.

- bpo-21527: Add a default number of workers to ThreadPoolExecutor equal to
  5 times the number of CPUs.  Patch by Claudiu Popa.

- bpo-22216: smtplib now resets its state more completely after a quit.  The
  most obvious consequence of the previous behavior was a STARTTLS failure
  during a connect/starttls/quit/connect/starttls sequence.

- bpo-22098: ctypes' BigEndianStructure and LittleEndianStructure now define
  an empty __slots__ so that subclasses don't always get an instance dict.
  Patch by Claudiu Popa.

- bpo-22185: Fix an occasional RuntimeError in threading.Condition.wait()
  caused by mutation of the waiters queue without holding the lock.  Patch
  by Doug Zongker.

- bpo-22287: On UNIX, _PyTime_gettimeofday() now uses
  clock_gettime(CLOCK_REALTIME) if available. As a side effect, Python now
  depends on the librt library on Solaris and on Linux (only with glibc
  older than 2.17).

- bpo-22182: Use e.args to unpack exceptions correctly in
  distutils.file_util.move_file. Patch by Claudiu Popa.

- The webbrowser module now uses subprocess's start_new_session=True rather
  than a potentially risky preexec_fn=os.setsid call.

- bpo-22042: signal.set_wakeup_fd(fd) now raises an exception if the file
  descriptor is in blocking mode.

- bpo-16808: inspect.stack() now returns a named tuple instead of a tuple.
  Patch by Daniel Shahaf.

- bpo-22236: Fixed Tkinter images copying operations in NoDefaultRoot mode.

- bpo-2527: Add a *globals* argument to timeit functions, in order to
  override the globals namespace in which the timed code is executed. Patch
  by Ben Roberts.

- bpo-22118: Switch urllib.parse to use RFC 3986 semantics for the
  resolution of relative URLs, rather than RFCs 1808 and 2396. Patch by
  Demian Brecht.

- bpo-21549: Added the "members" parameter to TarFile.list().

- bpo-19628: Allow compileall recursion depth to be specified with a -r

- bpo-15696: Add a __sizeof__ implementation for mmap objects on Windows.

- bpo-22068: Avoided reference loops with Variables and Fonts in Tkinter.

- bpo-22165: SimpleHTTPRequestHandler now supports undecodable file names.

- bpo-15381: Optimized line reading in io.BytesIO.

- bpo-8797: Raise HTTPError on failed Basic Authentication immediately.
  Initial patch by Sam Bull.

- bpo-20729: Restored the use of lazy iterkeys()/itervalues()/iteritems() in
  the mailbox module.

- bpo-21448: Changed FeedParser feed() to avoid O(N**2) behavior when
  parsing long line. Original patch by Raymond Hettinger.

- bpo-22184: The functools LRU Cache decorator factory now gives an earlier
  and clearer error message when the user forgets the required parameters.

- bpo-17923: glob() patterns ending with a slash no longer match non-dirs on
  AIX.  Based on patch by Delhallt.

- bpo-21725: Added support for RFC 6531 (SMTPUTF8) in smtpd.

- bpo-22176: Update the ctypes module's libffi to v3.1.  This release adds
  support for the Linux AArch64 and POWERPC ELF ABIv2 little endian

- bpo-5411: Added support for the "xztar" format in the shutil module.

- bpo-21121: Don't force 3rd party C extensions to be built with
  -Werror=declaration- after-statement.

- bpo-21975: Fixed crash when using uninitialized sqlite3.Row (in particular
  when unpickling pickled sqlite3.Row).  sqlite3.Row is now initialized in
  the __new__() method.

- bpo-20170: Convert posixmodule to use Argument Clinic.

- bpo-21539: Add an *exists_ok* argument to `Pathlib.mkdir()` to mimic
  `mkdir -p` and `os.makedirs()` functionality.  When true, ignore
  FileExistsErrors.  Patch by Berker Peksag.

- bpo-22127: Bypass IDNA for pure-ASCII host names in the socket module (in
  particular for numeric IPs).

- bpo-21047: set the default value for the *convert_charrefs* argument of
  HTMLParser to True.  Patch by Berker Peksag.

- Add an __all__ to html.entities.

- bpo-15114: the strict mode and argument of HTMLParser, HTMLParser.error,
  and the HTMLParserError exception have been removed.

- bpo-22085: Dropped support of Tk 8.3 in Tkinter.

- bpo-21580: Now Tkinter correctly handles bytes arguments passed to Tk. In
  particular this allows initializing images from binary data.

- bpo-22003: When initialized from a bytes object, io.BytesIO() now defers
  making a copy until it is mutated, improving performance and memory use on
  some use cases. Patch by David Wilson.

- bpo-22018: On Windows, signal.set_wakeup_fd() now also supports sockets. A
  side effect is that Python depends to the WinSock library.

- bpo-22054: Add os.get_blocking() and os.set_blocking() functions to get
  and set the blocking mode of a file descriptor (False if the O_NONBLOCK
  flag is set, True otherwise). These functions are not available on

- bpo-17172: Make turtledemo start as active on OS X even when run with
  subprocess. Patch by Lita Cho.

- bpo-21704: Fix build error for _multiprocessing when semaphores are not
  available. Patch by Arfrever Frehtes Taifersar Arahesis.

- bpo-20173: Convert sha1, sha256, sha512 and md5 to ArgumentClinic. Patch
  by Vajrasky Kok.

- Fix repr(_socket.socket) on Windows 64-bit: don't fail with OverflowError
  on closed socket. repr(socket.socket) already works fine.

- bpo-22033: Reprs of most Python implemened classes now contain actual
  class name instead of hardcoded one.

- bpo-21947: The dis module can now disassemble generator-iterator objects
  based on their gi_code attribute. Patch by Clement Rouault.

- bpo-16133: The asynchat.async_chat.handle_read() method now ignores
  BlockingIOError exceptions.

- bpo-22044: Fixed premature DECREF in call_tzinfo_method. Patch by Tom

- bpo-19884: readline: Disable the meta modifier key if stdout is not a
  terminal to not write the ANSI sequence ``"\033[1034h"`` into stdout. This
  sequence is used on some terminal (ex: TERM=xterm-256color") to enable
  support of 8 bit characters.

- bpo-4350: Removed a number of out-of-dated and non-working for a long time
  Tkinter methods.

- bpo-6167: Scrollbar.activate() now returns the name of active element if
  the argument is not specified.  Scrollbar.set() now always accepts only 2

- bpo-15275: Clean up and speed up the ntpath module.

- bpo-21888: plistlib's load() and loads() now work if the fmt parameter is

- bpo-22032: __qualname__ instead of __name__ is now always used to format
  fully qualified class names of Python implemented classes.

- bpo-22031: Reprs now always use hexadecimal format with the "0x" prefix
  when contain an id in form " at 0x...".

- bpo-22018: signal.set_wakeup_fd() now raises an OSError instead of a
  ValueError on ``fstat()`` failure.

- bpo-21044: now handles fileobj with an integer 'name'
  attribute.  Based on patch by Antoine Pietri.

- bpo-21966: Respect -q command-line option when code module is ran.

- bpo-19076: Don't pass the redundant 'file' argument to self.error().

- bpo-16382: Improve exception message of warnings.warn() for bad category.
  Initial patch by Phil Elson.

- bpo-21932: now uses a :c:func:`Py_ssize_t` type instead of
  :c:type:`int` for the size to support reading more than 2 GB at once. On
  Windows, the size is truncted to INT_MAX. As any call to, the OS
  may read less bytes than the number of requested bytes.

- bpo-21942: Fixed source file viewing in pydoc's server mode on Windows.

- bpo-11259: asynchat.async_chat().set_terminator() now raises a ValueError
  if the number of received bytes is negative.

- bpo-12523: asynchat.async_chat.push() now raises a TypeError if it doesn't
  get a bytes string

- bpo-21707: Add missing kwonlyargcount argument to

- bpo-20639: calling Path.with_suffix('') allows removing the suffix again.
  Patch by July Tikhonov.

- bpo-21714: Disallow the construction of invalid paths using
  Path.with_name().  Original patch by Antony Lee.

- bpo-15014: Added 'auth' method to smtplib to make implementing auth
  mechanisms simpler, and used it internally in the login method.

- bpo-21151: Fixed a segfault in the winreg module when ``None`` is passed
  as a ``REG_BINARY`` value to SetValueEx.  Patch by John Ehresman.

- bpo-21090: io.FileIO.readall() does not ignore I/O errors anymore. Before,
  it ignored I/O errors if at least the first C call read() succeed.

- bpo-5800: headers parameter of wsgiref.headers.Headers is now optional.
  Initial patch by Pablo Torres Navarrete and SilentGhost.

- bpo-21781: ssl.RAND_add() now supports strings longer than 2 GB.

- bpo-21679: Prevent extraneous fstat() calls during open().  Patch by
  Bohuslav Kabrda.

- bpo-21863: cProfile now displays the module name of C extension functions,
  in addition to their own name.

- bpo-11453: asyncore: emit a ResourceWarning when an unclosed file_wrapper
  object is destroyed. The destructor now closes the file if needed. The
  close() method can now be called twice: the second call does nothing.

- bpo-21858: Better handling of Python exceptions in the sqlite3 module.

- bpo-21476: Make sure the email.parser.BytesParser TextIOWrapper is
  discarded after parsing, so the input file isn't unexpectedly closed.

- bpo-20295: imghdr now recognizes OpenEXR format images.

- bpo-21729: Used the "with" statement in the dbm.dumb module to ensure
  files closing. Patch by Claudiu Popa.

- bpo-21491: socketserver: Fix a race condition in child processes reaping.

- bpo-21719: Added the ``st_file_attributes`` field to os.stat_result on

- bpo-21832: Require named tuple inputs to be exact strings.

- bpo-21722: The distutils "upload" command now exits with a non-zero return
  code when uploading fails.  Patch by Martin Dengler.

- bpo-21723: asyncio.Queue: support any type of number (ex: float) for the
  maximum size. Patch written by Vajrasky Kok.

- bpo-21711: support for "site-python" directories has now been removed from
  the site module (it was deprecated in 3.4).

- bpo-17552: new socket.sendfile() method allowing a file to be sent over a
  socket by using high-performance os.sendfile() on UNIX. Patch by Giampaolo

- bpo-18039: now always creates a new database when the flag
  has the value 'n'.  Patch by Claudiu Popa.

- bpo-21326: Add a new is_closed() method to asyncio.BaseEventLoop.
  run_forever() and run_until_complete() methods of asyncio.BaseEventLoop
  now raise an exception if the event loop was closed.

- bpo-21766: Prevent a security hole in CGIHTTPServer by URL unquoting paths
  before checking for a CGI script at that path.

- bpo-21310: Fixed possible resource leak in failed open().

- bpo-21256: Printout of keyword args should be in deterministic order in a
  mock function call. This will help to write better doctests.

- bpo-21677: Fixed chaining nonnormalized exceptions in io close() methods.

- bpo-11709: Fix the function to not fail when sys.stdin is not a
  valid file.

- bpo-21515: tempfile.TemporaryFile now uses os.O_TMPFILE flag is available.

- bpo-13223: Fix pydoc.writedoc so that the HTML documentation for methods
  that use 'self' in the example code is generated correctly.

- bpo-21463: In urllib.request, fix pruning of the FTP cache.

- bpo-21618: The subprocess module could fail to close open fds that were
  inherited by the calling process and already higher than POSIX resource
  limits would otherwise allow.  On systems with a functioning /proc/self/fd
  or /dev/fd interface the max is now ignored and all fds are closed.

- bpo-20383: Introduce importlib.util.module_from_spec() as the preferred
  way to create a new module.

- bpo-21552: Fixed possible integer overflow of too long string lengths in
  the tkinter module on 64-bit platforms.

- bpo-14315: The zipfile module now ignores extra fields in the central
  directory that are too short to be parsed instead of letting a
  struct.unpack error bubble up as this "bad data" appears in many real
  world zip files in the wild and is ignored by other zip tools.

- bpo-13742: Added "key" and "reverse" parameters to heapq.merge(). (First
  draft of patch contributed by Simon Sapin.)

- bpo-21402: tkinter.ttk now works when default root window is not set.

- bpo-3015: _tkinter.create() now creates tkapp object with wantobject=1 by

- bpo-10203: sqlite3.Row now truly supports sequence protocol.  In
  particular it supports reverse() and negative indices.  Original patch by
  Claudiu Popa.

- bpo-18807: If copying (no symlinks) specified for a venv, then the python
  interpreter aliases (python, python3) are now created by copying rather
  than symlinking.

- bpo-20197: Added support for the WebP image type in the imghdr module.
  Patch by Fabrice Aneche and Claudiu Popa.

- bpo-21513: Speedup some properties of IP addresses (IPv4Address,
  IPv6Address) such as .is_private or .is_multicast.

- bpo-21137: Improve the repr for threading.Lock() and its variants by
  showing the "locked" or "unlocked" status.  Patch by Berker Peksag.

- bpo-21538: The plistlib module now supports loading of binary plist files
  when reference or offset size is not a power of two.

- bpo-21455: Add a default backlog to socket.listen().

- bpo-21525: Most Tkinter methods which accepted tuples now accept lists

- bpo-22166: With the assistance of a new internal _codecs._forget_codec
  helping function, test_codecs now clears the encoding caches to avoid the
  appearance of a reference leak

- bpo-22236: Tkinter tests now don't reuse default root window.  New root
  window is created for every test class.

- bpo-10744: Fix PEP 3118 format strings on ctypes objects with a nontrivial

- bpo-20826: Optimize ipaddress.collapse_addresses().

- bpo-21487: Optimize ipaddress.summarize_address_range() and

- bpo-21486: Optimize parsing of netmasks in ipaddress.IPv4Network and

- bpo-13916: Disallowed the surrogatepass error handler for non UTF-\*

- bpo-20998: Fixed re.fullmatch() of repeated single character pattern with
  ignore case. Original patch by Matthew Barnett.

- bpo-21075: fileinput.FileInput now reads bytes from standard stream if
  binary mode is specified.  Patch by Sam Kimbrel.

- bpo-19775: Add a samefile() method to pathlib Path objects.  Initial patch
  by Vajrasky Kok.

- bpo-21226: Set up modules properly in PyImport_ExecCodeModuleObject (and

- bpo-21398: Fix a unicode error in the pydoc pager when the documentation
  contains characters not encodable to the stdout encoding.

- bpo-16531: ipaddress.IPv4Network and ipaddress.IPv6Network now accept an
  (address, netmask) tuple argument, so as to easily construct network
  objects from existing addresses.

- bpo-21156: is now a

- bpo-21424: Simplified and optimized heaqp.nlargest() and nmsmallest() to
  make fewer tuple comparisons.

- bpo-21396: Fix TextIOWrapper(..., write_through=True) to not force a
  flush() on the underlying binary stream.  Patch by akira.

- bpo-18314: Unlink now removes junctions on Windows. Patch by Kim Gräsman

- bpo-21088: Bugfix for curses.window.addch() regression in 3.4.0. In
  porting to Argument Clinic, the first two arguments were reversed.

- bpo-21407: _decimal: The module now supports function signatures.

- bpo-10650: Remove the non-standard 'watchexp' parameter from the
  Decimal.quantize() method in the Python version.  It had never been
  present in the C version.

- bpo-21469: Reduced the risk of false positives in robotparser by checking
  to make sure that robots.txt has been read or does not exist prior to
  returning True in can_fetch().

- bpo-19414: Have the OrderedDict mark deleted links as unusable. This gives
  an early failure if the link is deleted during iteration.

- bpo-21421: Add __slots__ to the MappingViews ABC. Patch by Josh Rosenberg.

- bpo-21101: Eliminate double hashing in the C speed-up code for

- bpo-21321: itertools.islice() now releases the reference to the source
  iterator when the slice is exhausted.  Patch by Anton Afanasyev.

- bpo-21057: TextIOWrapper now allows the underlying binary stream's read()
  or read1() method to return an arbitrary bytes-like object (such as a
  memoryview). Patch by Nikolaus Rath.

- bpo-20951: SSLSocket.send() now raises either SSLWantReadError or
  SSLWantWriteError on a non-blocking socket if the operation would block.
  Previously, it would return 0.  Patch by Nikolaus Rath.

- bpo-13248: removed previously deprecated asyncore.dispatcher __getattr__
  cheap inheritance hack.

- bpo-9815: assertRaises now tries to clear references to local variables in
  the exception's traceback.

- bpo-19940: ssl.cert_time_to_seconds() now interprets the given time string
  in the UTC timezone (as specified in RFC 5280), not the local timezone.

- bpo-13204: Calling sys.flags.__new__ would crash the interpreter, now it
  raises a TypeError.

- bpo-19385: Make operations on a closed dbm.dumb database always raise the
  same exception.

- bpo-21207: Detect when the os.urandom cached fd has been closed or
  replaced, and open it anew.

- bpo-21291: subprocess's Popen.wait() is now thread safe so that multiple
  threads may be calling wait() or poll() on a Popen instance at the same
  time without losing the Popen.returncode value.

- bpo-21127: Path objects can now be instantiated from str subclass
  instances (such as ``numpy.str_``).

- bpo-15002: urllib.response object to use _TemporaryFileWrapper (and
  _TemporaryFileCloser) facility. Provides a better way to handle file
  descriptor close. Patch contributed by Christian Theune.

- bpo-12220: mindom now raises a custom ValueError indicating it doesn't
  support spaces in URIs instead of letting a 'split' ValueError bubble up.

- bpo-21068: The ssl.PROTOCOL* constants are now enum members.

- bpo-21276: posixmodule: Don't define USE_XATTRS on KFreeBSD and the Hurd.

- bpo-21262: New method assert_not_called for Mock. It raises AssertionError
  if the mock has been called.

- bpo-21238: New keyword argument `unsafe` to Mock. It raises
  `AttributeError` incase of an attribute startswith assert or assret.

- bpo-20896: ssl.get_server_certificate() now uses PROTOCOL_SSLv23, not
  PROTOCOL_SSLv3, for maximum compatibility.

- bpo-21239: patch.stopall() didn't work deterministically when the same
  name was patched more than once.

- bpo-21203: Updated fileConfig and dictConfig to remove inconsistencies.
  Thanks to Jure Koren for the patch.

- bpo-21222: Passing name keyword argument to mock.create_autospec now

- bpo-21197: Add lib64 -> lib symlink in venvs on 64-bit non-OS X POSIX.

- bpo-17498: Some SMTP servers disconnect after certain errors, violating
  strict RFC conformance.  Instead of losing the error code when we issue
  the subsequent RSET, smtplib now returns the error code and defers raising
  the SMTPServerDisconnected error until the next command is issued.

- bpo-17826: setting an iterable side_effect on a mock function created by
  create_autospec now works. Patch by Kushal Das.

- bpo-7776: Fix ``Host:`` header and reconnection when using
  http.client.HTTPConnection.set_tunnel(). Patch by Nikolaus Rath.

- bpo-20968: unittest.mock.MagicMock now supports division. Patch by
  Johannes Baiter.

- bpo-21529: Fix arbitrary memory access in JSONDecoder.raw_decode with a
  negative second parameter. Bug reported by Guido Vranken. (See also:

- bpo-21169: getpass now handles non-ascii characters that the input stream
  encoding cannot encode by re-encoding using the replace error handler.

- bpo-21171: Fixed undocumented filter API of the rot13 codec. Patch by
  Berker Peksag.

- bpo-20539: Improved math.factorial error message for large positive inputs
  and changed exception type (OverflowError -> ValueError) for large
  negative inputs.

- bpo-21172: isinstance check relaxed from dict to collections.Mapping.

- bpo-21155: asyncio.EventLoop.create_unix_server() now raises a ValueError
  if path and sock are specified at the same time.

- bpo-21136: Avoid unnecessary normalization of Fractions resulting from
  power and other operations.  Patch by Raymond Hettinger.

- bpo-17621: Introduce importlib.util.LazyLoader.

- bpo-21076: signal module constants were turned into enums. Patch by
  Giampaolo Rodola'.

- bpo-20636: Improved the repr of Tkinter widgets.

- bpo-19505: The items, keys, and values views of OrderedDict now support
  reverse iteration using reversed().

- bpo-21149: Improved thread-safety in logging cleanup during interpreter
  shutdown. Thanks to Devin Jeanpierre for the patch.

- bpo-21058: Fix a leak of file descriptor in
  :func:`tempfile.NamedTemporaryFile`, close the file descriptor if
  :func:`` fails

- bpo-21200: Return None from pkgutil.get_loader() when __spec__ is missing.

- bpo-21013: Enhance ssl.create_default_context() when used for server side
  sockets to provide better security by default.

- bpo-20145: `assertRaisesRegex` and `assertWarnsRegex` now raise a
  TypeError if the second argument is not a string or compiled regex.

- bpo-20633: Replace relative import by absolute import.

- bpo-20980: Stop wrapping exception when using ThreadPool.

- bpo-21082: In os.makedirs, do not set the process-wide umask. Note this
  changes behavior of makedirs when exist_ok=True.

- bpo-20990: Fix issues found by pyflakes for multiprocessing.

- bpo-21015: SSL contexts will now automatically select an elliptic curve
  for ECDH key exchange on OpenSSL 1.0.2 and later, and otherwise default to

- bpo-21000: Improve the command-line interface of json.tool.

- bpo-20995: Enhance default ciphers used by the ssl module to enable better
  security and prioritize perfect forward secrecy.

- bpo-20884: Don't assume that __file__ is defined on importlib.__init__.

- bpo-21499: Ignore __builtins__ in several test_importlib.test_api tests.

- bpo-20627: xmlrpc.client.ServerProxy is now a context manager.

- bpo-19165: The formatter module now raises DeprecationWarning instead of

- bpo-13936: Remove the ability of datetime.time instances to be considered
  false in boolean contexts.

- bpo-18931: selectors module now supports /dev/poll on Solaris. Patch by
  Giampaolo Rodola'.

- bpo-19977: When the ``LC_TYPE`` locale is the POSIX locale (``C`` locale),
  :py:data:`sys.stdin` and :py:data:`sys.stdout` are now using the
  ``surrogateescape`` error handler, instead of the ``strict`` error

- bpo-20574: Implement incremental decoder for cp65001 code (Windows code
  page 65001, Microsoft UTF-8).

- bpo-20879: Delay the initialization of encoding and decoding tables for
  base32, ascii85 and base85 codecs in the base64 module, and delay the
  initialization of the unquote_to_bytes() table of the urllib.parse module,
  to not waste memory if these modules are not used.

- bpo-19157: Include the broadcast address in the usuable hosts for IPv6 in

- bpo-11599: When an external command (e.g. compiler) fails, distutils now
  prints out the whole command line (instead of just the command name) if
  the environment variable DISTUTILS_DEBUG is set.

- bpo-4931: distutils should not produce unhelpful "error: None" messages
  anymore. distutils.util.grok_environment_error is kept but doc-deprecated.

- bpo-20875: Prevent possible gzip "'read' is not defined" NameError. Patch
  by Claudiu Popa.

- bpo-11558: ``email.message.Message.attach`` now returns a more useful
  error message if ``attach`` is called on a message for which
  ``is_multipart`` is False.

- bpo-20283: RE pattern methods now accept the string keyword parameters as
  documented. The pattern and source keyword parameters are left as
  deprecated aliases.

- bpo-20778: Fix modulefinder to work with bytecode-only modules.

- bpo-20791: copy.copy() now doesn't make a copy when the input is a bytes
  object. Initial patch by Peter Otten.

- bpo-19748: On AIX, time.mktime() now raises an OverflowError for year
  outsize range [1902; 2037].

- bpo-19573: inspect.signature: Use enum for parameter kind constants.

- bpo-20726: inspect.signature: Make Signature and Parameter picklable.

- bpo-17373: Add inspect.Signature.from_callable method.

- bpo-20378: Improve repr of inspect.Signature and inspect.Parameter.

- bpo-20816: Fix inspect.getcallargs() to raise correct TypeError for
  missing keyword- only arguments. Patch by Jeremiah Lowin.

- bpo-20817: Fix inspect.getcallargs() to fail correctly if more than 3
  arguments are missing. Patch by Jeremiah Lowin.

- bpo-6676: Ensure a meaningful exception is raised when attempting to parse
  more than one XML document per pyexpat xmlparser instance. (Original
  patches by Hirokazu Yamamoto and Amaury Forgeot d'Arc, with suggested
  wording by David Gutteridge)

- bpo-21117: Fix inspect.signature to better support functools.partial. Due
  to the specifics of functools.partial implementation, positional-or-
  keyword arguments passed as keyword arguments become keyword-only.

- bpo-20334: inspect.Signature and inspect.Parameter are now hashable.
  Thanks to Antony Lee for bug reports and suggestions.

- bpo-15916: doctest.DocTestSuite returns an empty unittest.TestSuite
  instead of raising ValueError if it finds no tests

- bpo-21209: Fix asyncio.tasks.CoroWrapper to workaround a bug in yield-from
  implementation in CPythons prior to 3.4.1.

- asyncio: Add gi_{frame,running,code} properties to CoroWrapper (upstream
  issue #163).

- bpo-21311: Avoid exception in _osx_support with non-standard compiler
  configurations. Patch by John Szakmeister.

- bpo-11571: Ensure that the turtle window becomes the topmost window when
  launched on OS X.

- bpo-21801: Validate that __signature__ is None or an instance of

- bpo-21923: Prevent AttributeError in
  distutils.sysconfig.customize_compiler due to possible uninitialized

- bpo-21323: Fix http.server to again handle scripts in CGI subdirectories,
  broken by the fix for security issue #19435.  Patch by Zach Byrne.

- bpo-22733: Fix ffi_prep_args not zero-extending argument values correctly
  on 64-bit Windows.

- bpo-23302: Default to TCP_NODELAY=1 upon establishing an HTTPConnection.
  Removed use of hard-coded MSS as it's an optimization that's no longer
  needed with Nagle disabled.


- bpo-20577: Configuration of the max line length for the FormatParagraph
  extension has been moved from the General tab of the Idle preferences
  dialog to the FormatParagraph tab of the Config Extensions dialog. Patch
  by Tal Einat.

- bpo-16893: Update Idle doc chapter to match current Idle and add new

- bpo-3068: Add Idle extension configuration dialog to Options menu. Changes
  are written to HOME/.idlerc/config-extensions.cfg. Original patch by Tal

- bpo-16233: A module browser (File : Class Browser, Alt+C) requires an
  editor window with a filename.  When Class Browser is requested otherwise,
  from a shell, output window, or 'Untitled' editor, Idle no longer displays
  an error box. It now pops up an Open Module box (Alt+M). If a valid name
  is entered and a module is opened, a corresponding browser is also opened.

- bpo-4832: Save As to type Python files automatically adds .py to the name
  you enter (even if your system does not display it).  Some systems
  automatically add .txt when type is Text files.

- bpo-21986: Code objects are not normally pickled by the pickle module. To
  match this, they are no longer pickled when running under Idle.

- bpo-17390: Adjust Editor window title; remove 'Python', move version to

- bpo-14105: Idle debugger breakpoints no longer disappear when inserting or
  deleting lines.

- bpo-17172: Turtledemo can now be run from Idle. Currently, the entry is on
  the Help menu, but it may move to Run. Patch by Ramchandra Apt and Lita

- bpo-21765: Add support for non-ascii identifiers to HyperParser.

- bpo-21940: Add unittest for WidgetRedirector. Initial patch by Saimadhav

- bpo-18592: Add unittest for SearchDialogBase. Patch by Phil Webster.

- bpo-21694: Add unittest for ParenMatch. Patch by Saimadhav Heblikar.

- bpo-21686: add unittest for HyperParser. Original patch by Saimadhav

- bpo-12387: Add missing upper(lower)case versions of default Windows key
  bindings for Idle so Caps Lock does not disable them. Patch by Roger

- bpo-21695: Closing a Find-in-files output window while the search is still
  in progress no longer closes Idle.

- bpo-18910: Add unittest for textView. Patch by Phil Webster.

- bpo-18292: Add unittest for AutoExpand. Patch by Saihadhav Heblikar.

- bpo-18409: Add unittest for AutoComplete. Patch by Phil Webster.

- bpo-21477: - Improve framework, complete set of tests. Patches by
  Saimadhav Heblikar

- bpo-18104: Add idlelib/idle_test/ with a few sample tests to begin
  consolidating and improving human-validated tests of Idle. Change other
  files as needed to work with htest.  Running the module as __main__ runs
  all tests.

- bpo-21139: Change default paragraph width to 72, the PEP 8 recommendation.

- bpo-21284: Paragraph reformat test passes after user changes reformat

- bpo-17654: Ensure IDLE menus are customized properly on OS X for non-
  framework builds and for all variants of Tk.

- bpo-23180: Rename IDLE "Windows" menu item to "Window". Patch by Al


- bpo-15506: Use standard PKG_PROG_PKG_CONFIG autoconf macro in the
  configure script.

- bpo-22935: Allow the ssl module to be compiled if openssl doesn't support
  SSL 3.

- bpo-22592: Drop support of the Borland C compiler to build Python. The
  distutils module still supports it to build extensions.

- bpo-22591: Drop support of MS-DOS, especially of the DJGPP compiler (MS-
  DOS port of GCC).

- bpo-16537: Check whether self.extensions is empty in Patch by
  Jonathan Hosmer.

- bpo-22359: Remove incorrect uses of recursive make.  Patch by Jonas

- bpo-21958: Define HAVE_ROUND when building with Visual Studio 2013 and
  above.  Patch by Zachary Turner.

- bpo-18093: the programs that embed the CPython runtime are now in a
  separate "Programs" directory, rather than being kept in the Modules

- bpo-15759: "make suspicious", "make linkcheck" and "make doctest" in Doc/
  now display special message when and only when there are failures.

- bpo-21141: The Windows build process no longer attempts to find Perl,
  instead relying on OpenSSL source being configured and ready to build.
  The ``PCbuild\`` script has been re-written and re-named to
  ``PCbuild\``, and takes care of configuring OpenSSL source
  for both 32 and 64 bit platforms.  OpenSSL sources obtained from will always be pre-configured and ready to build.

- bpo-21037: Add a build option to enable AddressSanitizer support.

- bpo-19962: The Windows build process now creates "python.bat" in the root
  of the source tree, which passes all arguments through to the most
  recently built interpreter.

- bpo-21285: Refactor and fix curses configure check to always search in a
  ncursesw directory.

- bpo-15234: For BerkelyDB and Sqlite, only add the found library and
  include directories if they aren't already being searched. This avoids an
  explicit runtime library dependency.

- bpo-17861: Tools/scripts/ automatically regenerates
  Include/opcode.h from Lib/ if the latter gets any change.

- bpo-20644: OS X installer build support for documentation build changes in
  3.4.1: assume externally supplied sphinx-build is available in /usr/bin.

- bpo-20022: Eliminate use of deprecated bundlebuilder in OS X builds.

- bpo-15968: Incorporated Tcl, Tk, and Tix builds into the Windows build

- bpo-17095: Fix Modules/Setup *shared* support.

- bpo-21811: Anticipated fixes to support OS X versions > 10.9.

- bpo-21166: Prevent possible segfaults and other random failures of python
  --generate- posix-vars in pybuilddir.txt build target.

- bpo-18096: Fix library order returned by python-config.

- bpo-17219: Add library build dir for Python extension cross-builds.

- bpo-22919: Windows build updated to support VC 14.0 (Visual Studio 2015),
  which will be used for the official release.

- bpo-21236: Build _msi.pyd with cabinet.lib instead of fci.lib

- bpo-17128: Use private version of OpenSSL for OS X 10.5+ installer.


- bpo-14203: Remove obsolete support for view==NULL in PyBuffer_FillInfo(),
  bytearray_getbuffer(), bytesiobuf_getbuffer() and array_buffer_getbuf().
  All functions now raise BufferError in that case.

- bpo-22445: PyBuffer_IsContiguous() now implements precise contiguity
  tests, compatible with NumPy's NPY_RELAXED_STRIDES_CHECKING compilation
  flag.  Previously the function reported false negatives for corner cases.

- bpo-22079: PyType_Ready() now checks that statically allocated type has no
  dynamically allocated bases.

- bpo-22453: Removed non-documented macro PyObject_REPR().

- bpo-18395: Rename ``_Py_char2wchar()`` to :c:func:`Py_DecodeLocale`,
  rename ``_Py_wchar2char()`` to :c:func:`Py_EncodeLocale`, and document
  these functions.

- bpo-21233: Add new C functions: PyMem_RawCalloc(), PyMem_Calloc(),
  PyObject_Calloc(), _PyObject_GC_Calloc(). bytes(int) is now using
  ``calloc()`` instead of ``malloc()`` for large objects which is faster and
  use less memory.

- bpo-20942: PyImport_ImportFrozenModuleObject() no longer sets __file__ to
  match what importlib does; this affects _frozen_importlib as well as any
  module loaded using imp.init_frozen().


- bpo-19548: Update the codecs module documentation to better cover the
  distinction between text encodings and other codecs, together with other
  clarifications. Patch by Martin Panter.

- bpo-22394: Doc/Makefile now supports ``make venv PYTHON=../python`` to
  create a venv for generating the documentation, e.g., ``make html

- bpo-21514: The documentation of the json module now refers to new JSON RFC
  7159 instead of obsoleted RFC 4627.

- bpo-21777: The binary sequence methods on bytes and bytearray are now
  documented explicitly, rather than assuming users will be able to derive
  the expected behaviour from the behaviour of the corresponding str

- bpo-6916: undocument deprecated asynchat.fifo class.

- bpo-17386: Expanded functionality of the ``Doc/make.bat`` script to make
  it much more comparable to ``Doc/Makefile``.

- bpo-21312: Update the thread_foobar.h template file to include newer
  threading APIs. Patch by Jack McCracken.

- bpo-21043: Remove the recommendation for specific CA organizations and to
  mention the ability to load the OS certificates.

- bpo-20765: Add missing documentation for PurePath.with_name() and

- bpo-19407: New package installation and distribution guides based on the
  Python Packaging Authority tools. Existing guides have been retained as
  legacy links from the distutils docs, as they still contain some required
  reference material for tool developers that isn't recorded anywhere else.

- bpo-19697: Document cases where __main__.__spec__ is None.


- bpo-18982: Add tests for CLI of the calendar module.

- bpo-19548: Added some additional checks to test_codecs to ensure that
  statements in the updated documentation remain accurate. Patch by Martin

- bpo-22838: All test_re tests now work with unittest test discovery.

- bpo-22173: Update lib2to3 tests to use unittest test discovery.

- bpo-16000: Convert test_curses to use unittest.

- bpo-21456: Skip two tests in if _ssl module not
  present. Patch by Remi Pointel.

- bpo-20746: Fix test_pdb to run in refleak mode (-R).  Patch by Xavier de

- bpo-22060: test_ctypes has been somewhat cleaned up and simplified; it now
  uses unittest test discovery to find its tests.

- bpo-22104: no longer holds a reference to the suite of tests
  loaded from test modules that don't define test_main().

- bpo-22111: Assorted cleanups in test_imaplib.  Patch by Milan Oberkirch.

- bpo-22002: Added ``load_package_tests`` function to and used
  it to implement/augment test discovery in test_asyncio, test_email,
  test_importlib, test_json, and test_tools.

- bpo-21976: Fix test_ssl to accept LibreSSL version strings.  Thanks to
  William Orr.

- bpo-21918: Converted test_tools from a module to a package containing
  separate test files for each tested script.

- bpo-9554: Use modern unittest features in test_argparse. Initial patch by
  Denver Coneybeare and Radu Voicilas.

- bpo-20155: Changed HTTP method names in failing tests in test_httpservers
  so that packet filtering software (specifically Windows Base Filtering
  Engine) does not interfere with the transaction semantics expected by the

- bpo-19493: Refactored the ctypes test package to skip tests explicitly
  rather than silently.

- bpo-18492: All resources are now allowed when tests are not run by

- bpo-21634: Fix pystone micro-benchmark: use floor division instead of true
  division to benchmark integers instead of floating point numbers. Set
  pystone version to 1.2. Patch written by Lennart Regebro.

- bpo-21605: Added tests for Tkinter images.

- bpo-21493: Added test for ntpath.expanduser().  Original patch by Claudiu

- bpo-19925: Added tests for the spwd module. Original patch by Vajrasky

- bpo-21522: Added Tkinter tests for Listbox.itemconfigure(),
  PanedWindow.paneconfigure(), and Menu.entryconfigure().

- bpo-17756: Fix test_code test when run from the installed location.

- bpo-17752: Fix distutils tests when run from the installed location.

- bpo-18604: Consolidated checks for GUI availability.  All platforms now at
  least check whether Tk can be instantiated when the GUI resource is

- bpo-21275: Fix a socket test on KFreeBSD.

- bpo-21223: Pass test_site/test_startup_imports when some of the extensions
  are built as builtins.

- bpo-20635: Added tests for Tk geometry managers.

- Add test case for freeze.

- bpo-20743: Fix a reference leak in test_tcl.

- bpo-21097: Move test_namespace_pkgs into test_importlib.

- bpo-21503: Use test_both() consistently in test_importlib.

- bpo-20939: Avoid various network test failures due to new redirect of to use instead.

- bpo-20668: asyncio tests no longer rely on tests.txt file. (Patch by
  Vajrasky Kok)

- bpo-21093: Prevent failures of ctypes test_macholib on OS X if a copy of
  libz exists in $HOME/lib or /usr/local/lib.

- bpo-22770: Prevent some Tk segfaults on OS X when running gui tests.

- bpo-23211: Workaround test_logging failure on some OS X 10.6 systems.

- bpo-23345: Prevent test_ssl failures with large OpenSSL patch level values
  (like 0.9.8zc).


- bpo-22314: pydoc now works when the LINES environment variable is set.

- bpo-22615: Argument Clinic now supports the "type" argument for the int
  converter. This permits using the int converter with enums and typedefs.

- bpo-20076: The script no longer ignores UTF-8 mapping.

- bpo-20079: The script now can parse the SUPPORTED file
  from glibc sources and supports command line options for source paths.

- bpo-22201: Command-line interface of the zipfile module now correctly
  extracts ZIP files with directory entries.  Patch by Ryan Wilson.

- bpo-22120: For functions using an unsigned integer return converter,
  Argument Clinic now generates a cast to that type for the comparison to -1
  in the generated code.  (This suppresses a compilation warning.)

- bpo-18974: Tools/scripts/ now uses argparse instead of optparse.

- bpo-21906: Make Tools/scripts/ work in Python 3. Patch by Zachary

- bpo-21629: Fix Argument Clinic's "--converters" feature.

- Add support for ``yield from`` to 2to3.

- Add support for the PEP 465 matrix multiplication operator to 2to3.

- bpo-16047: Fix module exception list and __file__ handling in freeze.
  Patch by Meador Inge.

- bpo-11824: Consider ABI tags in freeze. Patch by Meador Inge.

- bpo-20535: PYTHONWARNING no longer affects the script. Patch
  by Arfrever Frehtes Taifersar Arahesis.


- bpo-23260: Update Windows installer

- The bundled version of Tcl/Tk has been updated to 8.6.3.  The most visible
  result of this change is the addition of new native file dialogs when
  running on Windows Vista or newer.  See Tcl/Tk's TIP 432 for more
  information.  Also, this version of Tcl/Tk includes support for Windows

- bpo-17896: The Windows build scripts now expect external library sources
  to be in ``PCbuild\..\externals`` rather than ``PCbuild\..\..``.

- bpo-17717: The Windows build scripts now use a copy of NASM pulled from to build OpenSSL.

- bpo-21907: Improved the batch scripts provided for building Python.

- bpo-22644: The bundled version of OpenSSL has been updated to 1.0.1j.

- bpo-10747: Use versioned labels in the Windows start menu. Patch by Olive

- bpo-22980: .pyd files with a version and platform tag (for example,
  ".cp35-win32.pyd") will now be loaded in preference to those without tags.

What's New in Python 3.4.0 final?

*Release date: 2014-03-16*


- bpo-20939: Fix test_geturl failure in test_urllibnet due to new redirect
  of to


- Merge in all documentation changes since branching 3.4.0rc1.

What's New in Python 3.4.0 release candidate 3?

*Release date: 2014-03-09*

Core and Builtins

- bpo-20786: Fix signatures for dict.__delitem__ and property.__delete__


- bpo-20839: Don't trigger a DeprecationWarning in the still supported
  pkgutil.get_loader() API when __loader__ isn't set on a module (nor when
  pkgutil.find_loader() is called directly).


- bpo-14512: Launch pydoc -b instead of pydocgui.pyw on Windows.

- bpo-20748: Uninstalling pip does not leave behind the pyc of the
  uninstaller anymore.

- bpo-20568: The Windows installer now installs the unversioned ``pip``
  command in addition to the versioned ``pip3`` and ``pip3.4`` commands.

- bpo-20757: The ensurepip helper for the Windows uninstaller now skips
  uninstalling pip (rather than failing) if the user has updated pip to a
  different version from the one bundled with ensurepip.

- bpo-20465: Update OS X and Windows installer builds to use SQLite

What's New in Python 3.4.0 release candidate 2?

*Release date: 2014-02-23*

Core and Builtins

- bpo-20625: Parameter names in __annotations__ were not mangled properly.
  Discovered by Jonas Wielicki, patch by Yury Selivanov.

- bpo-20261: In pickle, lookup __getnewargs__ and __getnewargs_ex__ on the
  type of the object.

- bpo-20619: Give the AST nodes of keyword-only arguments a column and line

- bpo-20526: Revert changes of issue #19466 which introduces a regression:
  don't clear anymore the state of Python threads early during the Python


- bpo-20710: The pydoc summary line no longer displays the "self" parameter
  for bound methods.

- bpo-20566: Change asyncio.as_completed() to use a Queue, to avoid O(N**2)

- bpo-20704: Implement new debug API in asyncio. Add new methods
  BaseEventLoop.set_debug() and BaseEventLoop.get_debug(). Add support for
  setting 'asyncio.tasks._DEBUG' variable with 'PYTHONASYNCIODEBUG'
  environment variable.

- asyncio: Refactoring and fixes: BaseEventLoop.sock_connect() raises an
  error if the address is not resolved; use __slots__ in Handle and
  TimerHandle; as_completed() and wait() raise TypeError if the passed list
  of Futures is a single Future; call_soon() and other 'call_*()' functions
  raise TypeError if the passed callback is a coroutine function;
  _ProactorBasePipeTransport uses _FlowControlMixin;
  WriteTransport.set_write_buffer_size() calls _maybe_pause_protocol() to
  consider pausing receiving if the watermark limits have changed; fix
  _check_resolved_address() for IPv6 address; and other minor improvements,
  along with multiple documentation updates.

- bpo-20684: Fix inspect.getfullargspec() to not to follow __wrapped__
  chains. Make its behaviour consistent with bound methods first argument.
  Patch by Nick Coghlan and Yury Selivanov.

- bpo-20681: Add new error handling API in asyncio. New APIs:
  loop.set_exception_handler(), loop.default_exception_handler(), and

- bpo-20673: Implement support for UNIX Domain Sockets in asyncio. New APIs:
  loop.create_unix_connection(), loop.create_unix_server(),
  streams.open_unix_connection(), and streams.start_unix_server().

- bpo-20616: Add a format() method to tracemalloc.Traceback.

- bpo-19744: the ensurepip installation step now just prints a warning to
  stderr rather than failing outright if SSL/TLS is unavailable. This allows
  local installation of POSIX builds without SSL/TLS support.

- bpo-20594: Avoid name clash with the libc function posix_close.


- bpo-20641: Run MSI custom actions (pip installation, pyc compilation) with
  the NoImpersonate flag, to support elevated execution (UAC).

- bpo-20221: Removed conflicting (or circular) hypot definition when
  compiled with VS 2010 or above.  Initial patch by Tabrez Mohammed.

- bpo-20609: Restored the ability to build 64-bit Windows binaries on 32-bit
  Windows, which was broken by the change in issue #19788.

What's New in Python 3.4.0 release candidate 1?

*Release date: 2014-02-10*

Core and Builtins

- bpo-19255: The builtins module is restored to initial value before
  cleaning other modules.  The sys and builtins modules are cleaned last.

- bpo-20588: Make Python-ast.c C89 compliant.

- bpo-20437: Fixed 22 potential bugs when deleting object references.

- bpo-20500: Displaying an exception at interpreter shutdown no longer risks
  triggering an assertion failure in PyObject_Str.

- bpo-20538: UTF-7 incremental decoder produced inconsistent string when
  input was truncated in BASE64 section.

- bpo-20404: io.TextIOWrapper (and hence the open() builtin) now uses the
  internal codec marking system added for issue #19619 to throw LookupError
  for known non- text encodings at stream construction time. The existing
  output type checks remain in place to deal with unmarked third party

- bpo-17162: Add PyType_GetSlot.

- bpo-20162: Fix an alignment issue in the siphash24() hash function which
  caused a crash on PowerPC 64-bit (ppc64).


- bpo-20530: The signatures for slot builtins have been updated to reflect
  the fact that they only accept positional-only arguments.

- bpo-20517: Functions in the os module that accept two filenames now
  register both filenames in the exception on failure.

- bpo-20563: The ipaddress module API is now considered stable.

- bpo-14983: email.generator now always adds a line end after each MIME
  boundary marker, instead of doing so only when there is an epilogue.  This
  fixes an RFC compliance bug and solves an issue with signed MIME parts.

- bpo-20540: Fix a performance regression (vs. Python 3.2) when layering a
  multiprocessing Connection over a TCP socket.  For small payloads, Nagle's
  algorithm would introduce idle delays before the entire transmission of a

- bpo-16983: the new email header parsing code will now decode encoded words
  that are (incorrectly) surrounded by quotes, and register a defect.

- bpo-19772: email.generator no longer mutates the message object when doing
  a down- transform from 8bit to 7bit CTEs.

- bpo-20536: the statistics module now correctly handle Decimal instances
  with positive exponents

- bpo-18805: the netmask/hostmask parsing in ipaddress now more reliably
  filters out illegal values and correctly allows any valid prefix length.

- bpo-20481: For at least Python 3.4, the statistics module will require
  that all inputs for a single operation be of a single consistent type, or
  else a mixed of ints and a single other consistent type. This avoids some
  interoperability issues that arose with the previous approach of coercing
  to a suitable common type.

- bpo-20478: the statistics module now treats collections.Counter inputs
  like any other iterable.

- bpo-17369: get_filename was raising an exception if the filename
  parameter's RFC2231 encoding was broken in certain ways.  This was a
  regression relative to python2.

- bpo-20013: Some imap servers disconnect if the current mailbox is deleted,
  and imaplib did not handle that case gracefully.  Now it handles the 'bye'

- bpo-20531: Revert 3.4 version of fix for #19063, and apply the 3.3
  version.  That is, do *not* raise an error if unicode is passed to

- bpo-20476: If a non-compat32 policy is used with any of the email parsers,
  EmailMessage is now used as the factory class.  The factory class should
  really come from the policy; that will get fixed in 3.5.

- bpo-19920: TarFile.list() no longer fails when outputs a listing
  containing non- encodable characters.  Based on patch by Vajrasky Kok.

- bpo-20515: Fix NULL pointer dereference introduced by issue #20368.

- bpo-19186: Restore namespacing of expat symbols inside the pyexpat module.

- bpo-20053: ensurepip (and hence venv) are no longer affected by the
  settings in the default pip configuration file.

- bpo-20426: When passing the re.DEBUG flag, re.compile() displays the debug
  output every time it is called, regardless of the compilation cache.

- bpo-20368: The null character now correctly passed from Tcl to Python.
  Improved error handling in variables-related commands.

- bpo-20435: Fix _pyio.StringIO.getvalue() to take into account newline
  translation settings.

- tracemalloc: Fix slicing traces and fix slicing a traceback.

- bpo-20354: Fix an alignment issue in the tracemalloc module on 64-bit
  platforms. Bug seen on 64-bit Linux when using "make profile-opt".

- bpo-17159: inspect.signature now accepts duck types of functions, which
  adds support for Cython functions. Initial patch by Stefan Behnel.

- bpo-18801: Fix inspect.classify_class_attrs to correctly classify
  object.__new__ and object.__init__.

- Fixed cmath.isinf's name in its argument parsing code.

- bpo-20311: poll and epoll now round the timeout away from zero, instead of
  rounding towards zero, in select and selectors modules:
  select.epoll.poll(), selectors.PollSelector.poll() and
  selectors.EpollSelector.poll(). For example, a timeout of one microsecond
  (1e-6) is now rounded to one millisecondi (1e-3), instead of being rounded
  to zero.  However, the granularity property and asyncio's resolution
  feature were removed again. (See also: bpo-20452)

- asyncio: Some refactoring; various fixes; add write flow control to unix
  pipes; Future.set_exception() instantiates the exception argument if it is
  a class; improved proactor pipe transport; support wait_for(f, None);
  don't log broken/disconnected pipes; use ValueError instead of assert for
  forbidden subprocess_{shell,exec} arguments; added a convenience API for
  subprocess management; added StreamReader.at_eof(); properly handle
  duplicate coroutines/futures in gather(), wait(), as_completed(); use a
  bytearray for buffering in StreamReader; and more.

- bpo-20288: fix handling of invalid numeric charrefs in HTMLParser.

- bpo-20424: Python implementation of io.StringIO now supports lone

- bpo-20308: inspect.signature now works on classes without user-defined
  __init__ or __new__ methods.

- bpo-20372: inspect.getfile (and a bunch of other inspect functions that
  use it) doesn't crash with unexpected AttributeError on classes defined in
  C without __module__.

- bpo-20356: inspect.signature formatting uses '/' to separate positional-
  only parameters from others.

- bpo-20223: inspect.signature now supports methods defined with

- bpo-19456: ntpath.join() now joins relative paths correctly when a drive
  is present.

- bpo-19077: tempfile.TemporaryDirectory cleanup no longer fails when called
  during shutdown.  Emitting resource warning in __del__ no longer fails.
  Original patch by Antoine Pitrou.

- bpo-20394: Silence Coverity warning in audioop module.

- bpo-20367: Fix behavior of concurrent.futures.as_completed() for duplicate
  arguments. Patch by Glenn Langford.

- bpo-8260: The read(), readline() and readlines() methods of
  codecs.StreamReader returned incomplete data when were called after
  readline() or read(size). Based on patch by Amaury Forgeot d'Arc.

- bpo-20105: the codec exception chaining now correctly sets the traceback
  of the original exception as its __traceback__ attribute.

- bpo-17481: inspect.getfullargspec() now uses inspect.signature() API.

- bpo-15304: concurrent.futures.wait() can block forever even if Futures
  have completed. Patch by Glenn Langford.

- bpo-14455: plistlib: fix serializing integers in the range of an unsigned
  long long but outside of the range of signed long long for binary plist


- bpo-20406: Use Python application icons for Idle window title bars. Patch
  mostly by Serhiy Storchaka.

- Update the python.gif icon for the Idle classbrowser and pathbowser from
  the old green snake to the new blue and yellow snakes.

- bpo-17721: Remove non-functional configuration dialog help button until we
  make it actually gives some help when clicked. Patch by Guilherme Simões.


- bpo-20532: Tests which use _testcapi now are marked as CPython only.

- bpo-19920: Added tests for TarFile.list().  Based on patch by Vajrasky

- bpo-19990: Added tests for the imghdr module.  Based on patch by Claudiu

- bpo-20474: Fix test_socket "unexpected success" failures on OS X 10.7+.


- bpo-20530: Argument Clinic's signature format has been revised again. The
  new syntax is highly human readable while still preventing false
  positives.  The syntax also extends Python syntax to denote "self" and
  positional-only parameters, allowing inspect.Signature objects to be
  totally accurate for all supported builtins in Python 3.4.

- bpo-20456: Argument Clinic now observes the C preprocessor conditional
  compilation statements of the C files it parses.  When a Clinic block is
  inside a conditional code, it adjusts its output to match, including
  automatically generating an empty methoddef macro.

- bpo-20456: Cloned functions in Argument Clinic now use the correct name,
  not the name of the function they were cloned from, for text strings
  inside generated code.

- bpo-20456: Fixed Argument Clinic's test suite and "--converters" feature.

- bpo-20456: Argument Clinic now allows specifying different names for a
  parameter in Python and C, using "as" on the parameter line.

- bpo-20326: Argument Clinic now uses a simple, unique signature to annotate
  text signatures in docstrings, resulting in fewer false positives.  "self"
  parameters are also explicitly marked, allowing inspect.Signature() to
  authoritatively detect (and skip) said parameters.

- bpo-20326: Argument Clinic now generates separate checksums for the input
  and output sections of the block, allowing external tools to verify that
  the input has not changed (and thus the output is not out-of-date).


- bpo-20465: Update SQLite shipped with OS X installer to 3.8.3.


- bpo-20517: Added new functions allowing OSError exceptions to reference
  two filenames instead of one: PyErr_SetFromErrnoWithFilenameObjects() and


- bpo-20488: Change wording to say importlib is *the* implementation of
  import instead of just *an* implementation.

- bpo-6386: Clarify in the tutorial that specifying a symlink to execute
  means the directory containing the executed script and not the symlink is
  added to sys.path.

What's New in Python 3.4.0 beta 3?

*Release date: 2014-01-26*

Core and Builtins

- bpo-20189: Four additional builtin types (PyTypeObject,
  PyMethodDescr_Type, _PyMethodWrapper_Type, and PyWrapperDescr_Type) have
  been modified to provide introspection information for builtins.

- bpo-17825: Cursor "^" is correctly positioned for SyntaxError and

- bpo-2382: SyntaxError cursor "^" is now written at correct position in
  most cases when multibyte characters are in line (before "^").  This still
  not works correctly with wide East Asian characters.

- bpo-18960: The first line of Python script could be executed twice when
  the source encoding was specified on the second line.  Now the source
  encoding declaration on the second line isn't effective if the first line
  contains anything except a comment.  'python -x' works now again with
  files with the source encoding declarations, and can be used to make
  Python batch files on Windows.


- asyncio: Various improvements and small changes not all covered by issues
  listed below.  E.g. wait_for() now cancels the inner task if the timeout
  occcurs; tweaked the set of exported symbols; renamed Empty/Full to
  QueueEmpty/QueueFull; "with (yield from lock)" now uses a separate context
  manager; readexactly() raises if not enough data was read; PTY support

- bpo-20311: asyncio: Add a granularity attribute to BaseEventLoop: maximum
  between the resolution of the BaseEventLoop.time() method and the
  resolution of the selector. The granuarility is used in the scheduler to
  round time and deadline.

- bpo-20311: selectors: Add a resolution attribute to BaseSelector.

- bpo-20189: unittest.mock now no longer assumes that any object for which
  it could get an inspect.Signature is a callable written in Python. Fix
  courtesy of Michael Foord.

- bpo-20317: ExitStack.__exit__ could create a self-referential loop if an
  exception raised by a cleanup operation already had its context set
  correctly (for example, by the @contextmanager decorator). The infinite
  loop this caused is now avoided by checking if the expected context is
  already set before trying to fix it.

- bpo-20374: Fix build with GNU readline >= 6.3.

- bpo-20262: Warnings are raised now when duplicate names are added in the
  ZIP file or too long ZIP file comment is truncated.

- bpo-20165: The unittest module no longer considers tests marked with
  @expectedFailure successful if they pass.

- bpo-18574: Added missing newline in 100-Continue reply from
  http.server.BaseHTTPRequestHandler. Patch by Nikolaus Rath.

- bpo-20270: urllib.urlparse now supports empty ports.

- bpo-20243: TarFile no longer raise ReadError when opened in write mode.

- bpo-20238: TarFile opened with external fileobj and "w:gz" mode didn't
  write complete output on close.

- bpo-20245: The open functions in the tarfile module now correctly handle
  empty mode.

- bpo-20242: Fixed basicConfig() format strings for the alternative
  formatting styles. Thanks to kespindler for the bug report and patch.

- bpo-20246: Fix buffer overflow in socket.recvfrom_into.

- bpo-20206: Fix edge case in email.quoprimime.encode where it truncated
  lines ending in a character needing encoding but no newline by using a
  more efficient algorithm that doesn't have the bug. (See also: bpo-5803)

- bpo-19082: Working xmlrpc.server and xmlrpc.client examples. Both in
  modules and in documentation. Initial patch contributed by Vajrasky Kok.

- bpo-20138: The wsgiref.application_uri() and wsgiref.request_uri()
  functions now conform to PEP 3333 when handle non-ASCII URLs.

- bpo-19097: Raise the correct Exception when cgi.FieldStorage is given an
  invalid fileobj.

- bpo-20152: Ported Python/import.c over to Argument Clinic.

- bpo-13107: argparse and optparse no longer raises an exception when output
  a help on environment with too small COLUMNS.  Based on patch by Elazar

- bpo-20207: Always disable SSLv2 except when PROTOCOL_SSLv2 is explicitly
  asked for.

- bpo-18960: The tokenize module now ignore the source encoding declaration
  on the second line if the first line contains anything except a comment.

- bpo-20078: Reading malformed zipfiles no longer hangs with 100% CPU

- bpo-20113: os.readv() and os.writev() now raise an OSError exception on
  error instead of returning -1.

- bpo-19719: Make,
  PathEntryFinder.find_loader(), and Loader.load_module() use PEP 451 APIs
  to help with backwards-compatibility.

- bpo-20144: inspect.Signature now supports parsing simple symbolic
  constants as parameter default values in __text_signature__.

- bpo-20072: Fixed multiple errors in tkinter with wantobjects is False.

- bpo-20229: Avoid plistlib deprecation warning in platform.mac_ver().

- bpo-14455: Fix some problems with the new binary plist support in


- bpo-17390: Add Python version to Idle editor window title bar. Original
  patches by Edmond Burnett and Kent Johnson.

- bpo-18960: IDLE now ignores the source encoding declaration on the second
  line if the first line contains anything except a comment.


- bpo-20358: Tests for curses.window.overlay and curses.window.overwrite no
  longer specify min{row,col} > max{row,col}.

- bpo-19804: The test_find_mac test in test_uuid is now skipped if the
  ifconfig executable is not available.

- bpo-19886: Use better estimated memory requirements for bigmem tests.


- bpo-20390: Argument Clinic's "file" output preset now defaults to

- bpo-20390: Argument Clinic's "class" directive syntax has been extended
  with two new required arguments: "typedef" and "type_object".

- bpo-20390: Argument Clinic: If __new__ or __init__ functions didn't use
  kwargs (or args), the PyArg_NoKeywords (or PyArg_NoPositional) calls
  generated are only run when the type object is an exact match.

- bpo-20390: Argument Clinic now fails if you have required parameters after
  optional parameters.

- bpo-20390: Argument Clinic converters now have a new template they can
  inject code into: "modifiers".  Code put there is run in the parsing
  function after argument parsing but before the call to the impl.

- bpo-20376: Argument Clinic now escapes backslashes in docstrings.

- bpo-20381: Argument Clinic now sanity checks the default argument when
  c_default is also specified, providing a nice failure message for
  disallowed values.

- bpo-20189: Argument Clinic now ensures that parser functions for __new__
  are always of type newfunc, the type of the tp_new slot. Similarly, parser
  functions for __init__ are now always of type initproc, the type of

- bpo-20189: Argument Clinic now suppresses the docstring for __new__ and
  __init__ functions if no docstring is provided in the input.

- bpo-20189: Argument Clinic now suppresses the "self" parameter in the impl
  for @staticmethod functions.

- bpo-20294: Argument Clinic now supports argument parsing for __new__ and
  __init__ functions.

- bpo-20299: Argument Clinic custom converters may now change the default
  value of c_default and py_default with a class member.

- bpo-20287: Argument Clinic's output is now configurable, allowing delaying
  its output or even redirecting it to a separate file.

- bpo-20226: Argument Clinic now permits simple expressions (e.g.
  "sys.maxsize - 1") as default values for parameters.

- bpo-19936: Added executable bits or shebang lines to Python scripts which
  requires them.  Disable executable bits and shebang lines in test and
  benchmark files in order to prevent using a random system python, and in
  source files of modules which don't provide command line interface.  Fixed
  shebang lines in the unittestgui and checkpip scripts.

- bpo-20268: Argument Clinic now supports cloning the parameters and return
  converter of existing functions.

- bpo-20228: Argument Clinic now has special support for class special

- bpo-20214: Fixed a number of small issues and documentation errors in
  Argument Clinic (see issue for details).

- bpo-20196: Fixed a bug where Argument Clinic did not generate correct
  parsing code for functions with positional-only parameters where all
  arguments are optional.

- bpo-18960: 2to3 and the script now ignore the source
  encoding declaration on the second line if the first line contains
  anything except a comment.

- bpo-19723: The marker comments Argument Clinic uses have been changed to
  improve readability.

- bpo-20157: When Argument Clinic renames a parameter because its name
  collides with a C keyword, it no longer exposes that rename to

- bpo-20141: Improved Argument Clinic's support for the PyArg_Parse "O!"
  format unit.

- bpo-20144: Argument Clinic now supports simple symbolic constants as
  parameter default values.

- bpo-20143: The line numbers reported in Argument Clinic errors are now
  more accurate.

- bpo-20142: Py_buffer variables generated by Argument Clinic are now
  initialized with a default value.


- bpo-12837: Silence a tautological comparison warning on OS X under Clang
  in socketmodule.c.

What's New in Python 3.4.0 beta 2?

*Release date: 2014-01-05*

Core and Builtins

- bpo-17432: Drop UCS2 from names of Unicode functions in python3.def.

- bpo-19526: Exclude all new API from the stable ABI. Exceptions can be made
  if a need is demonstrated.

- bpo-19969: PyBytes_FromFormatV() now raises an OverflowError if "%c"
  argument is not in range [0; 255].

- bpo-19995: %c, %o, %x, and %X now issue a DeprecationWarning on non-
  integer input; reworded docs to clarify that an integer type should define
  both __int__ and __index__.

- bpo-19787: PyThread_set_key_value() now always set the value. In Python
  3.3, the function did nothing if the key already exists (if the current
  value is a non-NULL pointer).

- bpo-14432: Remove the thread state field from the frame structure. Fix a
  crash when a generator is created in a C thread that is destroyed while
  the generator is still used. The issue was that a generator contains a
  frame, and the frame kept a reference to the Python state of the destroyed
  C thread. The crash occurs when a trace function is setup.

- bpo-19576: PyGILState_Ensure() now initializes threads. At startup, Python
  has no concrete GIL. If PyGILState_Ensure() is called from a new thread
  for the first time and PyEval_InitThreads() was not called yet, a GIL
  needs to be created.

- bpo-17576: Deprecation warning emitted now when __int__() or __index__()
  return not int instance.

- bpo-19932: Fix typo in import.h, missing whitespaces in function

- bpo-19736: Add module-level statvfs constants defined for GNU/glibc based

- bpo-20097: Fix bad use of "self" in importlib's WindowsRegistryFinder.

- bpo-19729: In str.format(), fix recursive expansion in format spec.

- bpo-19638: Fix possible crash / undefined behaviour from huge (more than 2
  billion characters) input strings in _Py_dg_strtod.


- bpo-20154: Deadlock in asyncio.StreamReader.readexactly().

- bpo-16113: Remove sha3 module again.

- bpo-20111: pathlib.Path.with_suffix() now sanity checks the given suffix.

- Fix breakage in TestSuite.countTestCases() introduced by issue #11798.

- bpo-20108: Avoid parameter name clash in inspect.getcallargs().

- bpo-19918: Fix PurePath.relative_to() under Windows.

- bpo-19422: Explicitly disallow non-SOCK_STREAM sockets in the ssl module,
  rather than silently let them emit clear text data.

- bpo-20046: Locale alias table no longer contains entities which can be
  calculated. Generalized support of the euro modifier.

- bpo-20027: Fixed locale aliases for devanagari locales.

- bpo-20067: Tkinter variables now work when wantobjects is false.

- bpo-19020: Tkinter now uses splitlist() instead of split() in configure

- bpo-19744: ensurepip now provides a better error message when Python is
  built without SSL/TLS support (pip currently requires that support to run,
  even if only operating with local wheel files)

- bpo-19734: ensurepip now ignores all pip environment variables to avoid
  odd behaviour based on user configuration settings

- Fix TypeError on " upload --show-response".

- bpo-20045: Fix " register --list-classifiers".

- bpo-18879: When a method is looked up on a temporary file, avoid closing
  the file before the method is possibly called.

- bpo-20037: Avoid crashes when opening a text file late at interpreter

- bpo-19967: Thanks to the PEP 442, asyncio.Future now uses a destructor to
  log uncaught exceptions, instead of the dedicated _TracebackLogger class.

- Added a Task.current_task() class method to asyncio.

- bpo-19850: Set SA_RESTART in asyncio when registering a signal handler to
  limit EINTR occurrences.

- Implemented write flow control in asyncio for proactor event loop

- Change write buffer in asyncio use to avoid O(N**2) behavior.  Make
  write()/sendto() accept bytearray/memoryview.

- bpo-20034: Updated alias mapping to most recent locale.alias file from distribution using

- bpo-5815: Fixed support for locales with modifiers.  Fixed support for
  locale encodings with hyphens.

- bpo-20026: Fix the sqlite module to handle correctly invalid isolation
  level (wrong type).

- bpo-18829: csv.Dialect() now checks type for delimiter, escapechar and
  quotechar fields.  Original patch by Vajrasky Kok.

- bpo-19855: uuid.getnode() on Unix now looks on the PATH for the
  executables used to find the mac address, with /sbin and /usr/sbin as

- bpo-20007: no more prematurely closes connection.
  Original patch by Simon Sapin.

- bpo-19946: multiprocessing now uses runpy to initialize __main__ in child
  processes when necessary, allowing it to correctly handle scripts without
  suffixes and submodules that use explicit relative imports or otherwise
  rely on parent modules being correctly imported prior to execution.

- bpo-19921: When Path.mkdir() is called with parents=True, any missing
  parent is created with the default permissions, ignoring the mode argument
  (mimicking the POSIX "mkdir -p" command).

- bpo-19887: Improve the Path.resolve() algorithm to support certain symlink

- bpo-19912: Fixed numerous bugs in ntpath.splitunc().

- bpo-19911: ntpath.splitdrive() now correctly processes the 'İ' character

- bpo-19532: python -m compileall with no filename/directory arguments now
  respects the -f and -q flags instead of ignoring them.

- bpo-19623: Fixed writing to unseekable files in the aifc module.

- bpo-19946: multiprocessing.spawn now raises ImportError when the module to
  be used as the main module cannot be imported.

- bpo-17919: select.poll.register() again works with poll.POLLNVAL on AIX.
  Fixed integer overflow in the eventmask parameter.

- bpo-19063: if a Charset's body_encoding was set to None, the email package
  would generate a message claiming the Content-Transfer-Encoding was 7bit,
  and produce garbage output for the content.  This now works. A couple of
  other set_payload mishandlings of non-ASCII are also fixed. In addition,
  calling set_payload with a string argument without specifying a charset
  now raises an error (this is a new error in 3.4).

- bpo-15475: Add __sizeof__ implementations for itertools objects.

- bpo-19944: Fix importlib.find_spec() so it imports parents as needed and
  move the function to importlib.util.

- bpo-19880: Fix a reference leak in unittest.TestCase. Explicitly break
  reference cycles between frames and the _Outcome instance.

- bpo-17429: platform.linux_distribution() now decodes files from the UTF-8
  encoding with the surrogateescape error handler, instead of decoding from
  the locale encoding in strict mode. It fixes the function on Fedora 19
  which is probably the first major distribution release with a non-ASCII
  name. Patch written by Toshio Kuratomi.

- bpo-19343: Expose FreeBSD-specific APIs in resource module.  Original
  patch by Koobs.

- bpo-19929: Call with 32768 within subprocess.Popen.communicate
  rather than 4096 for efficiency.  A microbenchmark shows Linux and OS X
  both using ~50% less cpu time this way.

- bpo-19506: Use a memoryview to avoid a data copy when piping data to stdin
  within subprocess.Popen.communicate.  5-10% less cpu usage.

- bpo-19876: selectors unregister() no longer raises ValueError or OSError
  if the FD is closed (as long as it was registered).

- bpo-19908: pathlib now joins relative Windows paths correctly when a drive
  is present. Original patch by Antoine Pitrou.

- bpo-19296: Silence compiler warning in dbm_open

- bpo-6784: Strings from Python 2 can now be unpickled as bytes objects by
  setting the encoding argument of Unpickler to be 'bytes'. Initial patch by
  Merlijn van Deen.

- bpo-19839: Fix regression in bz2 module's handling of non-bzip2 data at
  EOF, and analogous bug in lzma module.

- bpo-19881: Fix pickling bug where cpickle would emit bad pickle data for
  large bytes string (i.e., with size greater than 2**32-1).

- bpo-19138: doctest's IGNORE_EXCEPTION_DETAIL now allows a match when no
  exception detail exists (no colon following the exception's name, or a
  colon does follow but no text follows the colon).

- bpo-19927: Add __eq__ to path-based loaders in importlib.

- bpo-19827: On UNIX, setblocking() and settimeout() methods of
  socket.socket can now avoid a second syscall if the ioctl() function can
  be used, or if the non- blocking flag of the socket is unchanged.

- bpo-19785: smtplib now supports SSLContext.check_hostname and server name
  indication for TLS/SSL connections.

- bpo-19784: poplib now supports SSLContext.check_hostname and server name
  indication for TLS/SSL connections.

- bpo-19783: nntplib now supports SSLContext.check_hostname and server name
  indication for TLS/SSL connections.

- bpo-19782: imaplib now supports SSLContext.check_hostname and server name
  indication for TLS/SSL connections.

- bpo-20123: Fix pydoc.synopsis() for "binary" modules.

- bpo-19834: Support unpickling of exceptions pickled by Python 2.

- bpo-19781: ftplib now supports SSLContext.check_hostname and server name
  indication for TLS/SSL connections.

- bpo-19509: Add SSLContext.check_hostname to match the peer's certificate
  with server_hostname on handshake.

- bpo-15798: Fixed subprocess.Popen() to no longer fail if file descriptor
  0, 1 or 2 is closed.

- bpo-17897: Optimized unpickle prefetching.

- bpo-3693: Make the error message more helpful when the array.array()
  constructor is given a str. Move the array module typecode documentation
  to the docstring of the constructor.

- bpo-19088: Fixed incorrect caching of the copyreg module in
  object.__reduce__() and object.__reduce_ex__().

- bpo-19698: Removed exec_module() methods from
  importlib.machinery.BuiltinImporter and ExtensionFileLoader.

- bpo-18864: Added a setter for ModuleSpec.has_location.

- Fixed _pickle.Unpickler to not fail when loading empty strings as
  persistent IDs.

- bpo-11480: Fixed copy.copy to work with classes with custom metaclasses.
  Patch by Daniel Urban.

- bpo-6477: Added support for pickling the types of built-in singletons
  (i.e., Ellipsis, NotImplemented, None).

- bpo-19713: Add remaining PEP 451-related deprecations and move away from
  using find_module/find_loaer/load_module.

- bpo-19708: Update pkgutil to use the new importer APIs.

- bpo-19703: Update pydoc to use the new importer APIs.

- bpo-19851: Fixed a regression in reloading sub-modules.

- ssl.create_default_context() sets OP_NO_COMPRESSION to prevent CRIME.

- bpo-19802: Add socket.SO_PRIORITY.

- bpo-11508: Fixed uuid.getnode() and uuid.uuid1() on environment with
  virtual interface. Original patch by Kent Frazier.

- bpo-11489: JSON decoder now accepts lone surrogates.

- bpo-19545: Avoid chained exceptions while passing stray % to
  time.strptime().  Initial patch by Claudiu Popa.


- bpo-20058: sys.stdin.readline() in IDLE now always returns only one line.

- bpo-19481: print() of string subclass instance in IDLE no longer hangs.

- bpo-18270: Prevent possible IDLE AttributeError on OS X when no initial
  shell window is present.


- bpo-20055: Fix test_shutil under Windows with symlink privileges held.
  Patch by Vajrasky Kok.

- bpo-20070: Don't run test_urllib2net when network resources are not

- bpo-19938: Re-enabled test_bug_1333982 in test_dis, which had been
  disabled since 3.0 due to the changes in listcomp handling.

- bpo-19320: test_tcl no longer fails when wantobjects is false.

- bpo-19919: Fix flaky SSL test. connect_ex() sometimes returns EWOULDBLOCK
  on Windows or VMs hosted on Windows.

- bpo-19912: Added tests for ntpath.splitunc().

- bpo-19828: Fixed test_site when the whole suite is run with -S.

- bpo-19928: Implemented a test for repr() of cell objects.

- bpo-19535: Fixed test_docxmlrpc, test_functools, test_inspect, and
  test_statistics when python is run with -OO.

- bpo-19926: Removed unneeded test_main from test_abstract_numbers. Patch by
  Vajrasky Kok.

- bpo-19572: More skipped tests explicitly marked as skipped.

- bpo-19595: Re-enabled a long-disabled test in test_winsound. (See also:

- bpo-19588: Fixed tests in test_random that were silently skipped most of
  the time. Patch by Julian Gindi.


- bpo-19728: Enable pip installation by default on Windows.

- bpo-16136: Remove VMS support

- bpo-18215: Add script Tools/ssl/ to compile and
  run Python's unit tests with multiple versions of OpenSSL.

- bpo-19922: define _INCLUDE__STDC_A1_SOURCE in HP-UX to include mbstate_t
  for mbrtowc().

- bpo-19788: kill_python(_d).exe is now run as a PreBuildEvent on the
  pythoncore sub- project.  This should prevent build errors due a previous
  build's python(_d).exe still running.


- bpo-20265: Updated some parts of the Using Windows document.

- bpo-20266: Updated some parts of the Windows FAQ.

- bpo-20255: Updated the about and bugs pages.

- bpo-20253: Fixed a typo in the ipaddress docs that advertised an illegal
  attribute name.  Found by INADA Naoki.

- bpo-18840: Introduce the json module in the tutorial, and de-emphasize the
  pickle module.

- bpo-19845: Updated the Compiling Python on Windows section.

- bpo-19795: Improved markup of True/False constants.


- bpo-19659: Added documentation for Argument Clinic.

- bpo-19976: Argument Clinic METH_NOARGS functions now always take two

What's New in Python 3.4.0 beta 1?

*Release date: 2013-11-24*

Core and Builtins

- Use the repr of a module name in more places in import, especially

- bpo-19619: str.encode, bytes.decode and bytearray.decode now use an
  internal API to throw LookupError for known non-text encodings, rather
  than attempting the encoding or decoding operation and then throwing a
  TypeError for an unexpected output type. (The latter mechanism remains in
  place for third party non-text encodings)

- bpo-19183: Implement PEP 456 'secure and interchangeable hash algorithm'.
  Python now uses SipHash24 on all major platforms.

- bpo-12892: The utf-16* and utf-32* encoders no longer allow surrogate code
  points (U+D800-U+DFFF) to be encoded.  The utf-32* decoders no longer
  decode byte sequences that correspond to surrogate code points.  The
  surrogatepass error handler now works with the utf-16* and utf-32* codecs.
  Based on patches by Victor Stinner and Kang-Hao (Kenny) Lu.

- bpo-17806: Added keyword-argument support for "tabsize" to

- bpo-17828: Output type errors in str.encode(), bytes.decode() and
  bytearray.decode() now direct users to codecs.encode() or codecs.decode()
  as appropriate.

- bpo-17828: The interpreter now attempts to chain errors that occur in
  codec processing with a replacement exception of the same type that
  includes the codec name in the error message. It ensures it only does this
  when the creation of the replacement exception won't lose any information.

- bpo-19466: Clear the frames of daemon threads earlier during the Python
  shutdown to call object destructors. So "unclosed file" resource warnings
  are now correctly emitted for daemon threads.

- bpo-19514: Deduplicate some _Py_IDENTIFIER declarations. Patch by Andrei
  Dorian Duma.

- bpo-17936: Fix O(n**2) behaviour when adding or removing many subclasses
  of a given type.

- bpo-19428: zipimport now handles errors when reading truncated or invalid
  ZIP archive.

- bpo-18408: Add a new PyFrame_FastToLocalsWithError() function to handle
  exceptions when merging fast locals into f_locals of a frame.
  PyEval_GetLocals() now raises an exception and return NULL on failure.

- bpo-19369: Optimized the usage of __length_hint__().

- bpo-18603: Ensure that PyOS_mystricmp and PyOS_mystrnicmp are in the
  Python executable and not removed by the linker's optimizer.

- bpo-19306: Add extra hints to the faulthandler module's stack dumps that
  these are "upside down".


- bpo-3158: doctest can now find doctests in functions and methods written
  in C.

- bpo-13477: Added command line interface to the tarfile module. Original
  patch by Berker Peksag.

- bpo-19674: inspect.signature() now produces a correct signature for some

- bpo-19722: Added opcode.stack_effect(), which computes the stack effect of
  bytecode instructions.

- bpo-19735: Implement private function ssl._create_stdlib_context() to
  create SSLContext objects in Python's stdlib module. It provides a single
  configuration point and makes use of SSLContext.load_default_certs().

- bpo-16203: Add re.fullmatch() function and regex.fullmatch() method, which
  anchor the pattern at both ends of the string to match. Original patch by
  Matthew Barnett.

- bpo-13592: Improved the repr for regular expression pattern objects. Based
  on patch by Hugo Lopes Tavares.

- bpo-19641: Added the audioop.byteswap() function to convert big-endian
  samples to little-endian and vice versa.

- bpo-15204: Deprecated the 'U' mode in file-like objects.

- bpo-17810: Implement PEP 3154, pickle protocol 4.

- bpo-19668: Added support for the cp1125 encoding.

- bpo-19689: Add ssl.create_default_context() factory function. It creates a
  new SSLContext object with secure default settings.

- bpo-19727: os.utime(..., None) is now potentially more precise under

- bpo-17201: ZIP64 extensions now are enabled by default.  Patch by William

- bpo-19292: Add SSLContext.load_default_certs() to load default root CA
  certificates from default stores or system stores. By default the method
  loads CA certs for authentication of server certs.

- bpo-19673: Add pathlib to the stdlib as a provisional module (PEP 428).

- bpo-16596: pdb in a generator now properly skips over yield and yield from
  rather than stepping out of the generator into its caller.  (This is
  essential for stepping through asyncio coroutines.)

- bpo-17916: Added dis.Bytecode.from_traceback() and
  dis.Bytecode.current_offset to easily display "current instruction"
  markers in the new disassembly API (Patch by Claudiu Popa).

- bpo-19552: venv now supports bootstrapping pip into virtual environments

- bpo-17134: Finalize interface to Windows' certificate store. Cert and CRL
  enumeration are now two functions. enum_certificates() also returns
  purpose flags as set of OIDs.

- bpo-19555: Restore sysconfig.get_config_var('SO'), (and the distutils
  equivalent) with a DeprecationWarning pointing people at $EXT_SUFFIX.

- bpo-8813: Add SSLContext.verify_flags to change the verification flags of
  the context in order to enable certification revocation list (CRL) checks
  or strict X509 rules.

- bpo-18294: Fix the zlib module to make it 64-bit safe.

- bpo-19682: Fix compatibility issue with old version of OpenSSL that was
  introduced by Issue #18379.

- bpo-14455: plistlib now supports binary plists and has an updated API.

- bpo-19633: Fixed writing not compressed 16- and 32-bit wave files on big-
  endian platforms.

- bpo-18379: SSLSocket.getpeercert() returns CA issuer AIA fields, OCSP and
  CRL distribution points.

- bpo-18138: Implement cadata argument of SSLContext.load_verify_location()
  to load CA certificates and CRL from memory. It supports PEM and DER
  encoded strings.

- bpo-18775: Add name and block_size attribute to HMAC object. They now
  provide the same API elements as non-keyed cryptographic hash functions.

- bpo-17276: MD5 as default digestmod for HMAC is deprecated. The HMAC
  module supports digestmod names, e.g. hmac.HMAC('sha1').

- bpo-19449: in csv's writerow, handle non-string keys when generating the
  error message that certain keys are not in the 'fieldnames' list.

- bpo-13633: Added a new convert_charrefs keyword arg to HTMLParser that,
  when True, automatically converts all character references.

- bpo-2927: Added the unescape() function to the html module.

- bpo-8402: Added the escape() function to the glob module.

- bpo-17618: Add Base85 and Ascii85 encoding/decoding to the base64 module.

- bpo-19634: time.strftime("%y") now raises a ValueError on AIX when given a
  year before 1900.

- Fix to not cause an error when Python was
  compiled on a system with SO_REUSEPORT defined in the headers but run on a
  system with an OS kernel that does not support that reasonably new socket

- Fix compilation error under gcc of the ctypes module bundled libffi for

- bpo-19448: Add private API to SSL module to lookup ASN.1 objects by OID,
  NID, short name and long name.

- bpo-19282: now supports the context management protocol. (Initial
  patch by Claudiu Popa)

- bpo-8311: Added support for writing any bytes-like objects in the aifc,
  sunau, and wave modules.

- bpo-5202: Added support for unseekable files in the wave module.

- bpo-19544: Restore global option to ignore ~/.pydistutils.cfg in
  Distutils, accidentally removed in backout of distutils2 changes. (See
  also: bpo-1180)

- bpo-19523: Closed FileHandler leak which occurred when delay was set.

- bpo-19544: Restore support for --user and --group parameters to sdist
  command accidentally rolled back as part of the distutils2 rollback. (See
  also: bpo-6516)

- bpo-13674: Prevented time.strftime from crashing on Windows when given a
  year before 1900 and a format of %y.

- bpo-19406: implementation of the ensurepip module (part of PEP 453). Patch
  by Donald Stufft and Nick Coghlan.

- bpo-19544: Restore use of urllib over http allowing use of http_proxy for
  Distutils upload command, a feature accidentally lost in the rollback of
  distutils2. (See also: bpo-6286)

- bpo-19544: Restore the read_pkg_file method to
  distutils.dist.DistributionMetadata accidentally removed in the undo of
  distutils2. (See also: bpo-7457)

- bpo-16685: Added support for any bytes-like objects in the audioop module.
  Removed support for strings.

- bpo-7171: Add Windows implementation of ``inet_ntop`` and ``inet_pton`` to
  socket module. Patch by Atsuo Ishimoto.

- bpo-19261: Added support for writing 24-bit samples in the sunau module.

- bpo-1097797: Added CP273 encoding, used on IBM mainframes in Germany and
  Austria. Mapping provided by Michael Bierenfeld.

- bpo-1575020: Fixed support of 24-bit wave files on big-endian platforms.

- bpo-19378: Fixed a number of cases in the dis module where the new "file"
  parameter was not being honoured correctly

- bpo-19378: Removed the "dis.Bytecode.show_info" method

- bpo-19378: Renamed the "dis.Bytecode.display_code" method to
  "dis.Bytecode.dis" and converted it to returning a string rather than
  printing output.

- bpo-19378: the "line_offset" parameter in the new "dis.get_instructions"
  API has been renamed to "first_line" (and the default value and usage
  changed accordingly). This should reduce confusion with the more common
  use of "offset" in the dis docs to refer to bytecode offsets.

- bpo-18678: Corrected spwd struct member names in spwd module:
  sp_nam->sp_namp, and sp_pwd->sp_pwdp.  The old names are kept as extra
  structseq members, for backward compatibility.

- bpo-6157: Fixed tkinter.Text.debug().  tkinter.Text.bbox() now raises
  TypeError instead of TclError on wrong number of arguments.  Original
  patch by Guilherme Polo.

- bpo-10197: Rework subprocess.get[status]output to use subprocess
  functionality and thus to work on Windows. Patch by Nick Coghlan

- bpo-6160: The bbox() method of tkinter.Spinbox now returns a tuple of
  integers instead of a string.  Based on patch by Guilherme Polo.

- bpo-19403: contextlib.redirect_stdout is now reentrant

- bpo-19286: Directories in ``package_data`` are no longer added to the
  filelist, preventing failure outlined in the ticket.

- bpo-19480: HTMLParser now accepts all valid start-tag names as defined by
  the HTML5 standard.

- bpo-15114: The html.parser module now raises a DeprecationWarning when the
  strict argument of HTMLParser or the HTMLParser.error method are used.

- bpo-19410: Undo the special-casing removal of '' for

- bpo-19424: Fix the warnings module to accept filename containing surrogate

- bpo-19435: Fix directory traversal attack on CGIHttpRequestHandler.

- bpo-19227: Remove pthread_atfork() handler. The handler was added to solve
  #18747 but has caused issues.

- bpo-19420: Fix reference leak in module initialization code of

- bpo-19329: Optimized compiling charsets in regular expressions.

- bpo-19227: Try to fix deadlocks caused by re-seeding then OpenSSL pseudo-
  random number generator on fork().

- bpo-16037: HTTPMessage.readheaders() raises an HTTPException when more
  than 100 headers are read.  Adapted from patch by Jyrki Pulliainen.

- bpo-16040: CVE-2013-1752: nntplib: Limit maximum line lengths to 2048 to
  prevent readline() calls from consuming too much memory.  Patch by Jyrki

- bpo-16041: CVE-2013-1752: poplib: Limit maximum line lengths to 2048 to
  prevent readline() calls from consuming too much memory.  Patch by Jyrki

- bpo-17997: Change behavior of ``ssl.match_hostname()`` to follow RFC 6125,
  for security reasons.  It now doesn't match multiple wildcards nor
  wildcards inside IDN fragments.

- bpo-16039: CVE-2013-1752: Change use of readline in imaplib module to
  limit line length.  Patch by Emil Lind.

- bpo-19330: the unnecessary wrapper functions have been removed from the
  implementations of the new contextlib.redirect_stdout and
  contextlib.suppress context managers, which also ensures they provide
  reasonable help() output on instances

- bpo-19393: Fix symtable.symtable function to not be confused when there
  are functions or classes named "top".

- bpo-18685: Restore re performance to pre-PEP 393 levels.

- bpo-19339: telnetlib module is now using time.monotonic() when available
  to compute timeout.

- bpo-19399: fix sporadic test_subprocess failure.

- bpo-13234: Fix os.listdir to work with extended paths on Windows. Patch by
  Santoso Wijaya.

- bpo-19375: The site module adding a "site-python" directory to sys.path,
  if it exists, is now deprecated.

- bpo-19379: Lazily import linecache in the warnings module, to make startup
  with warnings faster until a warning gets printed.

- bpo-19288: Fixed the "in" operator of dbm.gnu databases for string
  argument.  Original patch by Arfrever Frehtes Taifersar Arahesis.

- bpo-19287: Fixed the "in" operator of dbm.ndbm databases for string
  argument.  Original patch by Arfrever Frehtes Taifersar Arahesis.

- bpo-19327: Fixed the working of regular expressions with too big charset.

- bpo-17400: New 'is_global' attribute for ipaddress to tell if an address
  is allocated by IANA for global or private networks.

- bpo-19350: Increasing the test coverage of macurl2path. Patch by Colin

- bpo-19365: Optimized the parsing of long replacement string in re.sub*()

- bpo-19352: Fix unittest discovery when a module can be reached through
  several paths (e.g. under Debian/Ubuntu with virtualenv).

- bpo-15207: Fix mimetypes to read from correct part of Windows registry
  Original patch by Dave Chambers

- bpo-16595: Add prlimit() to resource module.

- bpo-19324: Expose Linux-specific constants in resource module.

- Load SSL's error strings in hashlib.

- bpo-18527: Upgrade internal copy of zlib to 1.2.8.

- bpo-19274: Add a filterfunc parameter to PyZipFile.writepy.

- bpo-8964: fix platform._sys_version to handle IronPython 2.6+. Patch by
  Martin Matusiak.

- bpo-19413: Restore pre-3.3 reload() semantics of re-finding modules.

- bpo-18958: Improve error message for json.load(s) while passing a string
  that starts with a UTF-8 BOM.

- bpo-19307: Improve error message for json.load(s) while passing objects of
  the wrong type.

- bpo-16038: CVE-2013-1752: ftplib: Limit amount of data read by limiting
  the call to readline().  Original patch by Michał Jastrzębski and
  Giampaolo Rodola.

- bpo-17087: Improved the repr for regular expression match objects.


- bpo-19664: test_userdict's repr test no longer depends on the order of
  dict elements.

- bpo-19440: Clean up test_capi by removing an unnecessary __future__
  import, converting from test_main to unittest.main, and running the
  _testcapi module tests as subTests of a unittest TestCase method.

- bpo-19378: the main dis module tests are now run with both stdout
  redirection *and* passing an explicit file parameter

- bpo-19378: removed the not-actually-helpful assertInstructionMatches and
  assertBytecodeExactlyMatches helpers from bytecode_helper

- bpo-18702: All skipped tests now reported as skipped.

- bpo-19439: interpreter embedding tests are now executed on Windows (Patch
  by Zachary Ware)

- bpo-19085: Added basic tests for all tkinter widget options.

- bpo-19384: Fix test_py_compile for root user, patch by Claudiu Popa.


- bpo-18326: Clarify that list.sort's arguments are keyword-only.  Also,
  attempt to reduce confusion in the glossary by not saying there are
  different "types" of arguments and parameters.


- bpo-19358: "make clinic" now runs the Argument Clinic preprocessor over
  all CPython source files.

- Update SQLite to 3.8.1, xz to 5.0.5, and Tcl/Tk to 8.6.1 on Windows.

- bpo-16632: Enable DEP and ASLR on Windows.

- bpo-17791: Drop PREFIX and EXEC_PREFIX definitions from PC/pyconfig.h

- Add workaround for VS 2010 nmake clean issue. VS 2010 doesn't set up PATH
  for nmake.exe correctly.

- bpo-19550: Implement Windows installer changes of PEP 453 (ensurepip).

- bpo-19520: Fix compiler warning in the _sha3 module on 32bit Windows.

- bpo-19356: Avoid using a C variabled named "_self", it's a reserved word
  in some C compilers.

- bpo-15792: Correct build options on Win64. Patch by Jeremy Kloth.

- bpo-19373: Apply upstream change to Tk 8.5.15 fixing OS X 10.9 screen
  refresh problem for OS X installer build.

- bpo-19649: On OS X, the same set of file names are now installed in bin
  directories for all configurations: non-framework vs framework, and single
  arch vs universal builds.  pythonx.y-32 is now always installed for
  64-bit/32-bit universal builds.  The obsolete and undocumented pythonw*
  symlinks are no longer installed anywhere.

- bpo-19553: PEP 453 - "make install" and "make altinstall" now install or
  upgrade pip by default, using the bundled pip provided by the new
  ensurepip module.  A new configure option, --with-
  ensurepip[=upgrade|install|no], is available to override the default
  ensurepip "--upgrade" option.  The option can also be set with "make
  [alt]install ENSUREPIP=[upgrade|install|no]".

- bpo-19551: PEP 453 - the OS X installer now installs pip by default.

- Update third-party libraries for OS X installers: xz 5.0.3 -> 5.0.5,
  SQLite 3.7.13 -> 3.8.1

- bpo-15663: Revert OS X installer built-in Tcl/Tk support for 3.4.0b1. Some
  third-party projects, such as Matplotlib and PIL/Pillow, depended on being
  able to build with Tcl and Tk frameworks in /Library/Frameworks.


- bpo-19730: Argument Clinic now supports all the existing PyArg "format
  units" as legacy converters, as well as two new features: "self
  converters" and the "version" directive.

- bpo-19552: pyvenv now bootstraps pip into virtual environments by default
  (pass --without-pip to request the old behaviour)

- bpo-19390: Argument Clinic no longer accepts malformed Python and C ids.

What's New in Python 3.4.0 alpha 4?

*Release date: 2013-10-20*

Core and Builtins

- bpo-19301: Give classes and functions that are explicitly marked global a
  global qualname.

- bpo-19279: UTF-7 decoder no longer produces illegal strings.

- bpo-16612: Add "Argument Clinic", a compile-time preprocessor for C files
  to generate argument parsing code.  (See PEP 436.)

- bpo-18810: Shift stat calls in importlib.machinery.FileFinder such that
  the code is optimistic that if something exists in a directory named
  exactly like the possible package being searched for that it's in
  actuality a directory.

- bpo-18416: importlib.machinery.PathFinder now treats '' as the cwd and
  importlib.machinery.FileFinder no longer special-cases '' to '.'. This
  leads to modules imported from cwd to now possess an absolute file path
  for __file__ (this does not affect modules specified by path on the CLI
  but it does affect -m/runpy). It also allows FileFinder to be more
  consistent by not having an edge case.

- bpo-4555: All exported C symbols are now prefixed with either "Py" or

- bpo-19219: Speed up marshal.loads(), and make pyc files slightly (5% to
  10%) smaller.

- bpo-19221: Upgrade Unicode database to version 6.3.0.

- bpo-16742: The result of the C callback PyOS_ReadlineFunctionPointer must
  now be a string allocated by PyMem_RawMalloc() or PyMem_RawRealloc() (or
  NULL if an error occurred), instead of a string allocated by
  PyMem_Malloc() or PyMem_Realloc().

- bpo-19199: Remove ``PyThreadState.tick_counter`` field

- Fix macro expansion of _PyErr_OCCURRED(), and make sure to use it in at
  least one place so as to avoid regressions.

- bpo-19087: Improve bytearray allocation in order to allow cheap popping of
  data at the front (slice deletion).

- bpo-19014: memoryview.cast() is now allowed on zero-length views.

- bpo-18690: memoryview is now automatically registered with

- bpo-19078: memoryview now correctly supports the reversed builtin (Patch
  by Claudiu Popa)


- bpo-17457: unittest test discovery now works with namespace packages.
  Patch by Claudiu Popa.

- bpo-18235: Fix the sysconfig variables LDSHARED and BLDSHARED under AIX.
  Patch by David Edelsohn.

- bpo-18606: Add the new "statistics" module (PEP 450).  Contributed by
  Steven D'Aprano.

- bpo-12866: The audioop module now supports 24-bit samples.

- bpo-19254: Provide an optimized Python implementation of pbkdf2_hmac.

- bpo-19201: Add "x" mode (exclusive creation) in opening file to bz2, gzip
  and lzma modules. Patches by Tim Heaney and Vajrasky Kok. (See also:
  bpo-19222, bpo-19223)

- Fix a reference count leak in _sre.

- bpo-19262: Initial check in of the 'asyncio' package (a.k.a. Tulip, a.k.a.
  PEP 3156). There are no docs yet, and the PEP is slightly out of date with
  the code. This module will have *provisional* status in Python 3.4.

- bpo-19276: Fixed the wave module on 64-bit big-endian platforms.

- bpo-19266: Rename the new-in-3.4 ``contextlib.ignore`` context manager to
  ``contextlib.suppress`` in order to be more consistent with existing
  descriptions of that operation elsewhere in the language and standard
  library documentation (Patch by Zero Piraeus).

- bpo-18891: Completed the new email package (provisional) API additions by
  adding new classes EmailMessage, MIMEPart, and ContentManager.

- bpo-18281: Unused stat constants removed from `tarfile`.

- bpo-18999: Multiprocessing now supports 'contexts' with the same API as
  the module, but bound to specified start methods.

- bpo-18468: The re.split, re.findall, and re.sub functions and the group()
  and groups() methods of match object now always return a string or a bytes

- bpo-18725: The textwrap module now supports truncating multiline text.

- bpo-18776: atexit callbacks now display their full traceback when they
  raise an exception.

- bpo-17827: Add the missing documentation for ``codecs.encode`` and

- bpo-19218: Rename to _collections_abc in order to speed up
  interpreter start.

- bpo-18582: Add 'pbkdf2_hmac' to the hashlib module. It implements PKCS#5
  password-based key derivation functions with HMAC as pseudorandom

- bpo-19131: The aifc module now correctly reads and writes sampwidth of
  compressed streams.

- bpo-19209: Remove import of copyreg from the os module to speed up
  interpreter startup. stat_result and statvfs_result are now hard-coded to
  reside in the os module.

- bpo-19205: Don't import the 're' module in site and sysconfig module to
  speed up interpreter start.

- bpo-9548: Add a minimal "_bootlocale" module that is imported by the _io
  module instead of the full locale module.

- bpo-18764: Remove the 'print' alias for the PDB 'p' command so that it no
  longer shadows the print function.

- bpo-19158: A rare race in BoundedSemaphore could allow .release() too

- bpo-15805: Add contextlib.redirect_stdout().

- bpo-18716: Deprecate the formatter module.

- bpo-10712: 2to3 has a new "asserts" fixer that replaces deprecated names
  of unittest methods (e.g. failUnlessEqual -> assertEqual).

- bpo-18037: 2to3 now escapes ``'\u'`` and ``'\U'`` in native strings.

- bpo-17839: base64.decodebytes and base64.encodebytes now accept any object
  that exports a 1 dimensional array of bytes (this means the same is now
  also true for base64_codec)

- bpo-19132: The pprint module now supports compact mode.

- bpo-19137: The pprint module now correctly formats instances of set and
  frozenset subclasses.

- bpo-10042: functools.total_ordering now correctly handles NotImplemented
  being returned by the underlying comparison function (Patch by Katie

- bpo-19092: contextlib.ExitStack now correctly reraises exceptions from the
  __exit__ callbacks of inner context managers (Patch by Hrvoje Nikšić)

- bpo-12641: Avoid passing "-mno-cygwin" to the mingw32 compiler, except
  when necessary. Patch by Oscar Benjamin.

- bpo-5845: In, only load readline history from ~/.python_history if
  no history has been read already.  This avoids double writes to the
  history file at shutdown.

- Properly initialize all fields of a SSL object after allocation.

- bpo-19095: SSLSocket.getpeercert() now raises ValueError when the SSL
  handshake hasn't been done.

- bpo-4366: Fix building extensions on all platforms when --enable-shared is

- bpo-19030: Fixed `inspect.getmembers` and `inspect.classify_class_attrs`
  to attempt activating descriptors before falling back to a __dict__ search
  for faulty descriptors.  `inspect.classify_class_attrs` no longer returns
  Attributes whose home class is None.


- bpo-1772673: The type of `char*` arguments now changed to `const char*`.

- bpo-16129: Added a `Py_SetStandardStreamEncoding` pre-initialization API
  to allow embedding applications like Blender to force a particular
  encoding and error handler for the standard IO streams (initial patch by
  Bastien Montagne)


- bpo-19275: Fix test_site on AMD64 Snow Leopard

- bpo-14407: Fix unittest test discovery in test_concurrent_futures.

- bpo-18919: Unified and extended tests for audio modules: aifc, sunau and

- bpo-18714: Added tests for ``pdb.find_function()``.


- bpo-18758: Fixed and improved cross-references.

- bpo-18972: Modernize email examples and use the argparse module in them.


- bpo-19130: Correct PCbuild/readme.txt, Python 3.3 and 3.4 require VS 2010.

- bpo-15663: Update OS X 10.6+ installer to use Tcl/Tk 8.5.15.

- bpo-14499: Fix several problems with OS X universal build support:   1.
  ppc arch detection for extension module builds broke with Xcode 5   2. ppc
  arch detection in configure did not work on OS X 10.4   3. -sysroot and
  -arch flags were unnecessarily duplicated   4. there was no obvious way to
  configure an intel-32 only build.

- bpo-19019: Change the OS X installer build script to use CFLAGS instead of
  OPT for special build options.  By setting OPT, some compiler-specific
  options like -fwrapv were overridden and thus not used, which could result
  in broken interpreters when building with clang.

What's New in Python 3.4.0 alpha 3?

*Release date: 2013-09-29*

Core and Builtins

- bpo-18818: The "encodingname" part of PYTHONIOENCODING is now optional.

- bpo-19098: Prevent overflow in the compiler when the recursion limit is
  set absurdly high.


- bpo-18929: `inspect.classify_class_attrs()` now correctly finds class
  attributes returned by `dir()` that are located in the metaclass.

- bpo-18950: Fix miscellaneous bugs in the sunau module.
  Au_read.readframes() now updates current file position and reads correct
  number of frames from multichannel stream.  Au_write.writeframesraw() now
  correctly updates current file position.  Au_read.getnframes() now returns
  an integer (as in Python 2). Au_read and Au_write now correctly works with
  file object if start file position is not a zero.

- bpo-18594: The fast path for collections.Counter() was never taken due to
  an over- restrictive type check.

- bpo-19053: ZipExtFile.read1() with non-zero argument no more returns empty
  bytes until end of data.

- logging: added support for Unix domain sockets to SocketHandler and

- bpo-18996: TestCase.assertEqual() now more cleverly shorten differing
  strings in error report.

- bpo-19034: repr() for tkinter.Tcl_Obj now exposes string reperesentation.

- bpo-18978: ``urllib.request.Request`` now allows the method to be
  indicated on the class and no longer sets it to None in ``__init__``.

- bpo-18626: the inspect module now offers a basic command line
  introspection interface (Initial patch by Claudiu Popa)

- bpo-3015: Fixed tkinter with wantobject=False.  Any Tcl command call
  returned empty string.

- bpo-19037: The mailbox module now makes all changes to maildir files
  before moving them into place, to avoid race conditions with other
  programs that may be accessing the maildir directory.

- bpo-14984: On POSIX systems, when netrc is called without a filename
  argument (and therefore is reading the user's $HOME/.netrc file), it now
  enforces the same security rules as typical ftp clients: the .netrc file
  must be owned by the user that owns the process and must not be readable
  by any other user.

- bpo-18873: The tokenize module now detects Python source code encoding
  only in comment lines.

- bpo-17764: Enable http.server to bind to a user specified network
  interface.  Patch contributed by Malte Swart.

- bpo-18937: Add an assertLogs() context manager to unittest.TestCase to
  ensure that a block of code emits a message using the logging module.

- bpo-17324: Fix http.server's request handling case on trailing '/'. Patch
  contributed by Vajrasky Kok.

- bpo-19018: The heapq.merge() function no longer suppresses IndexError in
  the underlying iterables.

- bpo-18784: The uuid module no longer attempts to load libc via ctypes.CDLL
  if all the necessary functions have already been found in libuuid.  Patch
  by Evgeny Sologubov.

- The :envvar:`PYTHONFAULTHANDLER` environment variable now only enables the
  faulthandler module if the variable is non-empty. Same behaviour than
  other variables like :envvar:`PYTHONDONTWRITEBYTECODE`.

- bpo-1565525: New function ``traceback.clear_frames`` will clear the local
  variables of all the stack frames referenced by a traceback object.


- bpo-18952: Fix regression in support data downloads introduced when was converted to a package. Regression noticed by Zachary


- bpo-18873: IDLE now detects Python source code encoding only in comment

- bpo-18988: The "Tab" key now works when a word is already autocompleted.


- bpo-17003: Unified the size argument names in the io module with common


- bpo-18596: Support the use of address sanity checking in recent versions
  of clang and GCC by appropriately marking known false alarms in the small
  object allocator. Patch contributed by Dhiru Kholia.


- bpo-18873: 2to3 and the script now detect Python source
  code encoding only in comment lines.

What's New in Python 3.4.0 alpha 2?

*Release date: 2013-09-09*

Core and Builtins

- bpo-18942: sys._debugmallocstats() output was damaged on Windows.

- bpo-18571: Implementation of the PEP 446: file descriptors and file
  handles are now created non-inheritable; add functions
  os.get/set_inheritable(), os.get/set_handle_inheritable() and

- bpo-11619: The parser and the import machinery do not encode Unicode
  filenames anymore on Windows.

- bpo-18808: Non-daemon threads are now automatically joined when a sub-
  interpreter is shutdown (it would previously dump a fatal error).

- Remove support for compiling on systems without getcwd().

- bpo-18774: Remove last bits of GNU PTH thread code and thread_pth.h.

- bpo-18771: Add optimization to set object lookups to reduce the cost of
  hash collisions.  The core idea is to inspect a second key/hash pair for
  each cache line retrieved.

- bpo-16105: When a signal handler fails to write to the file descriptor
  registered with ``signal.set_wakeup_fd()``, report an exception instead of
  ignoring the error.

- bpo-18722: Remove uses of the "register" keyword in C code.

- bpo-18667: Add missing "HAVE_FCHOWNAT" symbol to posix._have_functions.

- bpo-16499: Add command line option for isolated mode.

- bpo-15301: Parsing fd, uid, and gid parameters for builtins in
  Modules/posixmodule.c is now far more robust.

- bpo-18368: PyOS_StdioReadline() no longer leaks memory when realloc()

- bpo-17934: Add a clear() method to frame objects, to help clean up
  expensive details (local variables) and break reference cycles.

- bpo-18780: %-formatting codes %d, %i, and %u now treat int-subclasses as
  int (displays value of int-subclass instead of str(int-subclass) ).


- bpo-18808: Thread.join() now waits for the underlying thread state to be
  destroyed before returning.  This prevents unpredictable aborts in
  Py_EndInterpreter() when some non-daemon threads are still running.

- bpo-18458: Prevent crashes with newer versions of libedit.  Its readline
  emulation has changed from 0-based indexing to 1-based like gnu readline.

- bpo-18852: Handle case of ``readline.__doc__`` being ``None`` in the new
  readline activation code in ````.

- bpo-18672: Fixed format specifiers for Py_ssize_t in debugging output in
  the _sre module.

- bpo-18830: inspect.getclasstree() no longer produces duplicate entries
  even when input list contains duplicates.

- bpo-18878: now supports the context management protocol.  Based
  on patches by Claudiu Popa and R. David Murray.

- bpo-18909: Fix _tkinter.tkapp.interpaddr() on Windows 64-bit, don't cast
  64-bit pointer to long (32 bits).

- bpo-18876: The FileIO.mode attribute now better reflects the actual mode
  under which the file was opened.  Patch by Erik Bray.

- bpo-16853: Add new selectors module.

- bpo-18882: Add threading.main_thread() function.

- bpo-18901: The sunau getparams method now returns a namedtuple rather than
  a plain tuple.  Patch by Claudiu Popa.

- bpo-17487: The result of the wave getparams method now is pickleable
  again. Patch by Claudiu Popa.

- bpo-18756: os.urandom() now uses a lazily-opened persistent file
  descriptor, so as to avoid using many file descriptors when run in
  parallel from multiple threads.

- bpo-18418: After fork(), reinit all threads states, not only active ones.
  Patch by A. Jesse Jiryu Davis.

- bpo-17974: Switch unittest from using getopt to using argparse.

- bpo-11798: TestSuite now drops references to own tests after execution.

- bpo-16611: http.cookie now correctly parses the 'secure' and 'httponly'
  cookie flags.

- bpo-11973: Fix a problem in kevent. The flags and fflags fields are now
  properly handled as unsigned.

- bpo-18807: ``pyvenv`` now takes a --copies argument allowing copies
  instead of symlinks even where symlinks are available and the default.

- bpo-18538: ``python -m dis`` now uses argparse for argument processing.
  Patch by Michele Orrù.

- bpo-18394: Close cgi.FieldStorage's optional file.

- bpo-17702: On error, os.environb now suppresses the exception context when
  raising a new KeyError with the original key.

- bpo-16809: Fixed some tkinter incompatibilities with Tcl/Tk 8.6.

- bpo-16809: Tkinter's splitlist() and split() methods now accept Tcl_Obj

- bpo-18324: set_payload now correctly handles binary input.  This also
  supersedes the previous fixes for #14360, #1717, and #16564.

- bpo-18794: Add a fileno() method and a closed attribute to select.devpoll

- bpo-17119: Fixed integer overflows when processing large strings and
  tuples in the tkinter module.

- bpo-18747: Re-seed OpenSSL's pseudo-random number generator after fork. A
  pthread_atfork() parent handler is used to seed the PRNG with pid, time
  and some stack data.

- bpo-8865: Concurrent invocation of select.poll.poll() now raises a
  RuntimeError exception.  Patch by Christian Schubert.

- bpo-18777: The ssl module now uses the new CRYPTO_THREADID API of OpenSSL
  1.0.0+ instead of the deprecated CRYPTO id callback function.

- bpo-18768: Correct doc string of RAND_edg(). Patch by Vajrasky Kok.

- bpo-18178: Fix ctypes on BSD. dlmalloc.c was compiled twice which broke
  malloc weak symbols.

- bpo-18709: Fix CVE-2013-4238. The SSL module now handles NULL bytes inside
  subjectAltName correctly. Formerly the module has used OpenSSL's
  GENERAL_NAME_print() function to get the string representation of ASN.1
  strings for ``rfc822Name`` (email), ``dNSName`` (DNS) and
  ``uniformResourceIdentifier`` (URI).

- bpo-18701: Remove support of old CPython versions (<3.0) from C code.

- bpo-18756: Improve error reporting in os.urandom() when the failure is due
  to something else than /dev/urandom not existing (for example, exhausting
  the file descriptor limit).

- bpo-18673: Add O_TMPFILE to os module. O_TMPFILE requires Linux kernel
  3.11 or newer. It's only defined on system with 3.11 uapi headers, too.

- bpo-18532: Change the builtin hash algorithms' names to lower case names
  as promised by hashlib's documentation.

- bpo-8713: add new spwan and forkserver start methods, and new functions
  get_all_start_methods, get_start_method, and set_start_method, to

- bpo-18405: Improve the entropy of crypt.mksalt().

- bpo-12015: The tempfile module now uses a suffix of 8 random characters
  instead of 6, to reduce the risk of filename collision. The entropy was
  reduced when uppercase letters were removed from the charset used to
  generate random characters.

- bpo-18585: Add :func:`textwrap.shorten` to collapse and truncate a piece
  of text to a given length.

- bpo-18598: Tweak exception message for importlib.import_module() to
  include the module name when a key argument is missing.

- bpo-19151: Fix docstring and use of _get_supported_file_loaders() to
  reflect 2-tuples.

- bpo-19152: Add ExtensionFileLoader.get_filename().

- bpo-18676: Change 'positive' to 'non-negative' in put and get
  docstrings and ValueError messages. Patch by Zhongyue Luo

- Fix refcounting issue with extension types in tkinter.

- bpo-8112: xlmrpc.server's DocXMLRPCServer server no longer raises an error
  if methods have annotations; it now correctly displays the annotations.

- bpo-18600: Added policy argument to email.message.Message.as_string, and
  as_bytes and __bytes__ methods to Message.

- bpo-18671: Output more information when logging exceptions occur.

- bpo-18621: Prevent the site module's patched builtins from keeping too
  many references alive for too long.

- bpo-4885: Add weakref support to mmap objects.  Patch by Valerie Lambert.

- bpo-8860: Fixed rounding in timedelta constructor.

- bpo-18849: Fixed a Windows-specific tempfile bug where collision with an
  existing directory caused mkstemp and related APIs to fail instead of
  retrying. Report and fix by Vlad Shcherbina.

- bpo-18920: argparse's default destination for the version action (-v,
  --version) has also been changed to stdout, to match the Python


- bpo-18623: Factor out the _SuppressCoreFiles context manager into  Patch by Valerie Lambert.

- bpo-12037: Fix test_email for desktop Windows.

- bpo-15507: test_subprocess's test_send_signal could fail if the test
  runner were run in an environment where the process inherited an ignore
  setting for SIGINT. Restore the SIGINT handler to the desired
  KeyboardInterrupt raising one during that test.

- bpo-16799: Switched from getopt to argparse style in regrtest's argument
  parsing. Added more tests for regrtest's argument parsing.

- bpo-18792: Use "" or "::1" instead of "localhost" as much as
  possible, since "localhost" goes through a DNS lookup under recent Windows


- bpo-18489: Add tests for SearchEngine. Original patch by Phil Webster.


- bpo-18743: Fix references to non-existent "StringIO" module.

- bpo-18783: Removed existing mentions of Python long type in docstrings,
  error messages and comments.


- bpo-1584: Provide configure options to override default search paths for
  Tcl and Tk when building _tkinter.

- bpo-15663: Tcl/Tk 8.5.14 is now included with the OS X 10.6+ 64-/32-bit
  installer.  It is no longer necessary to install a third-party version of
  Tcl/Tk 8.5 to work around the problems in the Apple-supplied Tcl/Tk 8.5
  shipped in OS X 10.6 and later releases.


- bpo-18922: Now The Lib/ and Tools/i18n/ scripts write
  their version strings to stdout, and not to sderr.

What's New in Python 3.4.0 alpha 1?

*Release date: 2013-08-03*

Core and Builtins

- bpo-16741: Fix an error reporting in int().

- bpo-17899: Fix rare file descriptor leak in os.listdir().

- bpo-10241: Clear extension module dict copies at interpreter shutdown.
  Patch by Neil Schemenauer, minimally modified.

- bpo-9035: ismount now recognises volumes mounted below a drive root on
  Windows. Original patch by Atsuo Ishimoto.

- bpo-18214: Improve finalization of Python modules to avoid setting their
  globals to None, in most cases.

- bpo-18112: PEP 442 implementation (safe object finalization).

- bpo-18552: Check return value of PyArena_AddPyObject() in

- bpo-18560: Fix potential NULL pointer dereference in sum().

- bpo-18520: Add a new PyStructSequence_InitType2() function, same than
  PyStructSequence_InitType() except that it has a return value (0 on
  success, -1 on error).

- bpo-15905: Fix theoretical buffer overflow in handling of sys.argv[0],
  prefix and exec_prefix if the operation system does not obey MAXPATHLEN.

- bpo-18408: Fix many various bugs in code handling errors, especially on
  memory allocation failure (MemoryError).

- bpo-18344: Fix potential ref-leaks in _bufferedreader_read_all().

- bpo-18342: Use the repr of a module name when an import fails when using
  ``from ... import ...``.

- bpo-17872: Fix a segfault in marshal.load() when input stream returns more
  bytes than requested.

- bpo-18338: `python --version` now prints version string to stdout, and not
  to stderr. Patch by Berker Peksag and Michael Dickens.

- bpo-18426: Fix NULL pointer dereference in C extension import when
  PyModule_GetDef() returns an error.

- bpo-17206: On Windows, increase the stack size from 2 MB to 4.2 MB to fix
  a stack overflow in the marshal module (fix a crash in test_marshal).
  Patch written by Jeremy Kloth.

- bpo-3329: Implement the PEP 445: Add new APIs to customize Python memory

- bpo-18328: Reorder ops in PyThreadState_Delete*() functions. Now the
  tstate is first removed from TLS and then deallocated.

- bpo-13483: Use VirtualAlloc in obmalloc on Windows.

- bpo-18184: PyUnicode_FromFormat() and PyUnicode_FromFormatV() now raise
  OverflowError when an argument of %c format is out of range.

- bpo-18111: The min() and max() functions now support a default argument to
  be returned instead of raising a ValueError on an empty sequence.
  (Contributed by Julian Berman.)

- bpo-18137: Detect integer overflow on precision in float.__format__() and

- bpo-18183: Fix various unicode operations on strings with large unicode

- bpo-18180: Fix ref leak in _PyImport_GetDynLoadWindows().

- bpo-18038: SyntaxError raised during compilation sources with illegal
  encoding now always contains an encoding name.

- bpo-17931: Resolve confusion on Windows between pids and process handles.

- Tweak the exception message when the magic number or size value in a
  bytecode file is truncated.

- bpo-17932: Fix an integer overflow issue on Windows 64-bit in iterators:
  change the C type of seqiterobject.it_index from long to Py_ssize_t.

- bpo-18065: Don't set __path__ to the package name for frozen packages.

- bpo-18088: When reloading a module, unconditionally reset all relevant
  attributes on the module (e.g. __name__, __loader__, __package__,
  __file__, __cached__).

- bpo-17937: Try harder to collect cyclic garbage at shutdown.

- bpo-12370: Prevent class bodies from interfering with the __class__

- bpo-17644: Fix a crash in str.format when curly braces are used in square

- bpo-17237: Fix crash in the ASCII decoder on m68k.

- bpo-17927: Frame objects kept arguments alive if they had been copied into
  a cell, even if the cell was cleared.

- bpo-1545463: At shutdown, defer finalization of codec modules so that
  stderr remains usable.

- bpo-7330: Implement width and precision (ex: "%5.3s") for the format
  string of PyUnicode_FromFormat() function, original patch written by Ysj

- bpo-1545463: Global variables caught in reference cycles are now garbage-
  collected at shutdown.

- bpo-17094: Clear stale thread states after fork().  Note that this is a
  potentially disruptive change since it may release some system resources
  which would otherwise remain perpetually alive (e.g. database connections
  kept in thread-local storage).

- bpo-17408: Avoid using an obsolete instance of the copyreg module when the
  interpreter is shutdown and then started again.

- bpo-5845: Enable tab-completion in the interactive interpreter by default,
  thanks to a new sys.__interactivehook__.

- bpo-17115: Module initialization now includes setting __package__ and
  __loader__ attributes to None. (See also: bpo-17116)

- bpo-17853: Ensure locals of a class that shadow free variables always win
  over the closures.

- bpo-17863: In the interactive console, don't loop forever if the encoding
  can't be fetched from stdin.

- bpo-17867: Raise an ImportError if __import__ is not found in

- bpo-18698: Ensure importlib.reload() returns the module out of

- bpo-17857: Prevent build failures with pre-3.5.0 versions of sqlite3, such
  as was shipped with Centos 5 and Mac OS X 10.4.

- bpo-17413: sys.settrace callbacks were being passed a string instead of an
  exception instance for the 'value' element of the arg tuple if the
  exception originated from C code; now an exception instance is always

- bpo-17782: Fix undefined behaviour on platforms where ``struct
  timespec``'s "tv_nsec" member is not a C long.

- bpo-17722: When looking up __round__, resolve descriptors.

- bpo-16061: Speed up str.replace() for replacing 1-character strings.

- bpo-17715: Fix segmentation fault from raising an exception in a __trunc__

- bpo-17643: Add __callback__ attribute to weakref.ref.

- bpo-16447: Fixed potential segmentation fault when setting __name__ on a

- bpo-17669: Fix crash involving finalization of generators using yield

- bpo-14439: Python now prints the traceback on runpy failure at startup.

- bpo-17469: Fix _Py_GetAllocatedBlocks() and sys.getallocatedblocks() when
  running on valgrind.

- bpo-17619: Make input() check for Ctrl-C correctly on Windows.

- bpo-17357: Add missing verbosity messages for -v/-vv that were lost during
  the importlib transition.

- bpo-17610: Don't rely on non-standard behavior of the C qsort() function.

- bpo-17323: The "[X refs, Y blocks]" printed by debug builds has been
  disabled by default.  It can be re-enabled with the `-X showrefcount`

- bpo-17328: Fix possible refleak in dict.setdefault.

- bpo-17275: Corrected class name in init error messages of the C version of
  BufferedWriter and BufferedRandom.

- bpo-7963: Fixed misleading error message that issued when object is called
  without arguments.

- bpo-8745: Small speed up zipimport on Windows. Patch by Catalin Iacob.

- bpo-5308: Raise ValueError when marshalling too large object (a sequence
  with size >= 2**31), instead of producing illegal marshal data.

- bpo-12983: Bytes literals with invalid ``\x`` escape now raise a
  SyntaxError and a full traceback including line number.

- bpo-16967: In function definition, evaluate positional defaults before
  keyword-only defaults.

- bpo-17173: Remove uses of locale-dependent C functions (isalpha() etc.) in
  the interpreter.

- bpo-17137: When a Unicode string is resized, the internal wide character
  string (wstr) format is now cleared.

- bpo-17043: The unicode-internal decoder no longer read past the end of
  input buffer.

- bpo-17098: All modules now have __loader__ set even if they pre-exist the
  bootstrapping of importlib.

- bpo-16979: Fix error handling bugs in the unicode-escape-decode decoder.

- bpo-16772: The base argument to the int constructor no longer accepts
  floats, or other non-integer objects with an __int__ method.  Objects with
  an __index__ method are now accepted.

- bpo-10156: In the interpreter's initialization phase, unicode globals are
  now initialized dynamically as needed.

- bpo-16980: Fix processing of escaped non-ascii bytes in the unicode-
  escape-decode decoder.

- bpo-16975: Fix error handling bug in the escape-decode bytes decoder.

- bpo-14850: Now a charmap decoder treats U+FFFE as "undefined mapping" in
  any mapping, not only in a string.

- bpo-16613: Add *m* argument to ``collections.Chainmap.new_child`` to allow
  the new child map to be specified explicitly.

- bpo-16730: importlib.machinery.FileFinder now no longers raises an
  exception when trying to populate its cache and it finds out the directory
  is unreadable or has turned into a file. Reported and diagnosed by David

- bpo-16906: Fix a logic error that prevented most static strings from being

- bpo-11461: Fix the incremental UTF-16 decoder. Original patch by Amaury
  Forgeot d'Arc.

- bpo-16856: Fix a segmentation fault from calling repr() on a dict with a
  key whose repr raise an exception.

- bpo-16367: Fix FileIO.readall() on Windows for files larger than 2 GB.

- bpo-16761: Calling int() with base argument only now raises TypeError.

- bpo-16759: Support the full DWORD (unsigned long) range in Reg2Py when
  retrieving a REG_DWORD value. This corrects functions like
  winreg.QueryValueEx that may have been returning truncated values.

- bpo-14420: Support the full DWORD (unsigned long) range in Py2Reg when
  passed a REG_DWORD value. Fixes OverflowError in winreg.SetValueEx.

- bpo-11939: Set the st_dev attribute of stat_result to allow Windows to
  take advantage of the os.path.samefile/sameopenfile/samestat
  implementations used by other platforms.

- bpo-16772: The int() constructor's second argument (base) no longer
  accepts non integer values.  Consistent with the behavior in Python 2.

- bpo-14470: Remove w9xpopen support per PEP 11.

- bpo-9856: Replace deprecation warning with raising TypeError in
  object.__format__. Patch by Florent Xicluna.

- bpo-16597: In buffered and text IO, call close() on the underlying stream
  if invoking flush() fails.

- bpo-16722: In the bytes() constructor, try to call __bytes__ on the
  argument before __index__.

- bpo-16421: loading multiple modules from one shared object is now handled
  correctly (previously, the first module loaded from that file was silently
  returned). Patch by Václav Šmilauer.

- bpo-16602: When a weakref's target was part of a long deallocation chain,
  the object could remain reachable through its weakref even though its
  refcount had dropped to zero.

- bpo-16495: Remove extraneous NULL encoding check from bytes_decode().

- bpo-16619: Create NameConstant AST class to represent None, True, and
  False literals. As a result, these constants are never loaded at runtime
  from builtins.

- bpo-16455: On FreeBSD and Solaris, if the locale is C, the
  ASCII/surrogateescape codec is now used (instead of the locale encoding)
  to decode the command line arguments. This change fixes inconsistencies
  with os.fsencode() and os.fsdecode(), because these operating systems
  announce an ASCII locale encoding, but actually use the ISO-8859-1
  encoding in practice.

- bpo-16562: Optimize dict equality testing.  Patch by Serhiy Storchaka.

- bpo-16588: Silence unused-but-set warnings in Python/thread_pthread

- bpo-16592: stringlib_bytes_join doesn't raise MemoryError on allocation

- bpo-16546: Fix: ast.YieldFrom argument is now mandatory.

- bpo-16514: Fix regression causing a traceback when sys.path[0] is None
  (actually, any non-string or non-bytes type).

- bpo-16306: Fix multiple error messages when unknown command line
  parameters where passed to the interpreter.  Patch by Hieu Nguyen.

- bpo-16215: Fix potential double memory free in str.replace().  Patch by
  Serhiy Storchaka.

- bpo-16290: A float return value from the __complex__ special method is no
  longer accepted in the complex() constructor.

- bpo-16416: On Mac OS X, operating system data are now always
  encoded/decoded to/from UTF-8/surrogateescape, instead of the locale
  encoding (which may be ASCII if no locale environment variable is set), to
  avoid inconsistencies with os.fsencode() and os.fsdecode() functions which
  are already using UTF-8/surrogateescape.

- bpo-16453: Fix equality testing of dead weakref objects.

- bpo-9535: Fix pending signals that have been received but not yet handled
  by Python to not persist after os.fork() in the child process.

- bpo-14794: Fix slice.indices to return correct results for huge values,
  rather than raising OverflowError.

- bpo-15001: fix segfault on "del sys.modules['__main__']". Patch by Victor

- bpo-8271: the utf-8 decoder now outputs the correct number of U+FFFD
  characters when used with the 'replace' error handler on invalid utf-8
  sequences.  Patch by Serhiy Storchaka, tests by Ezio Melotti.

- bpo-5765: Apply a hard recursion limit in the compiler instead of blowing
  the stack and segfaulting. Initial patch by Andrea Griffini.

- bpo-16402: When slicing a range, fix shadowing of exceptions from

- bpo-16336: fix input checking in the surrogatepass error handler. Patch by
  Serhiy Storchaka.

- bpo-8401: assigning an int to a bytearray slice (e.g. b[3:4] = 5) now
  raises an error.

- bpo-7317: Display full tracebacks when an error occurs asynchronously.
  Patch by Alon Horev with update by Alexey Kachayev.

- bpo-16309: Make PYTHONPATH="" behavior the same as if PYTHONPATH not set
  at all.

- bpo-10189: Improve the error reporting of SyntaxErrors related to global
  and nonlocal statements.

- Fix segfaults on setting __qualname__ on builtin types and attempting to
  delete it on any type.

- bpo-14625: Rewrite the UTF-32 decoder. It is now 3x to 4x faster. Patch
  written by Serhiy Storchaka.

- bpo-16345: Fix an infinite loop when ``fromkeys`` on a dict subclass
  received a nonempty dict from the constructor.

- bpo-16271: Fix strange bugs that resulted from __qualname__ appearing in a
  class's __dict__ and on type.

- bpo-12805: Make bytes.join and bytearray.join faster when the separator is
  empty. Patch by Serhiy Storchaka.

- bpo-6074: Ensure cached bytecode files can always be updated by the user
  that created them, even when the source file is read-only.

- bpo-15958: bytes.join and bytearray.join now accept arbitrary buffer

- bpo-14783: Improve int() docstring and switch docstrings for str(),
  range(), and slice() to use multi-line signatures.

- bpo-16160: Subclass support now works for types.SimpleNamespace.

- bpo-16148: Implement PEP 424, adding operator.length_hint and

- Upgrade Unicode data (UCD) to version 6.2.

- bpo-15379: Fix passing of non-BMP characters as integers for the charmap
  decoder (already working as unicode strings).  Patch by Serhiy Storchaka.

- bpo-15144: Fix possible integer overflow when handling pointers as integer
  values, by using `Py_uintptr_t` instead of `size_t`.  Patch by Serhiy

- bpo-15965: Explicitly cast `AT_FDCWD` as (int).  Required on Solaris 10
  (which defines `AT_FDCWD` as ``0xffd19553``), harmless on other platforms.

- bpo-15839: Convert SystemErrors in `super()` to RuntimeErrors.

- bpo-15448: Buffered IO now frees the buffer when closed, instead of when

- bpo-15846: Fix SystemError which happened when using `ast.parse()` in an
  exception handler on code with syntax errors.

- bpo-15897: zipimport.c doesn't check return value of fseek(). Patch by
  Felipe Cruz.

- bpo-15801: Make sure mappings passed to '%' formatting are actually

- bpo-15111: __import__ should propagate ImportError when raised as a side-
  effect of a module triggered from using fromlist.

- bpo-15022: Add pickle and comparison support to types.SimpleNamespace.


- bpo-4331: Added functools.partialmethod (Initial patch by Alon Horev)

- bpo-13461: Fix a crash in the TextIOWrapper.tell method on 64-bit
  platforms.  Patch by Yogesh Chaudhari.

- bpo-18681: Fix a NameError in importlib.reload() (noticed by Weizhao Li).

- bpo-14323: Expanded the number of digits in the coefficients for the RGB
  -- YIQ conversions so that they match the FCC NTSC versions.

- bpo-17998: Fix an internal error in regular expression engine.

- bpo-17557: Fix os.getgroups() to work with the modified behavior of
  getgroups(2) on OS X 10.8.  Original patch by Mateusz Lenik.

- bpo-18608: Avoid keeping a strong reference to the locale module inside
  the _io module.

- bpo-18619: Fix atexit leaking callbacks registered from sub-interpreters,
  and make it GC-aware.

- bpo-15699: The readline module now uses PEP 3121-style module
  initialization, so as to reclaim allocated resources (Python callbacks) at
  shutdown.  Original patch by Robin Schreiber.

- bpo-17616: now supports the context management protocol.

- bpo-18599: Fix name attribute of _sha1.sha1() object. It now returns
  'SHA1' instead of 'SHA'.

- bpo-13266: Added inspect.unwrap to easily unravel __wrapped__ chains
  (initial patch by Daniel Urban and Aaron Iles)

- bpo-18561: Skip name in ctypes' _build_callargs() if name is NULL.

- bpo-18559: Fix NULL pointer dereference error in _pickle module

- bpo-18556: Check the return type of PyUnicode_AsWideChar() in ctype's

- bpo-17818: aifc.getparams now returns a namedtuple.

- bpo-18549: Eliminate dead code in socket_ntohl()

- bpo-18530: Remove additional stat call from posixpath.ismount. Patch by
  Alex Gaynor.

- bpo-18514: Fix unreachable Py_DECREF() call in PyCData_FromBaseObj()

- bpo-9177: Calling read() or write() now raises ValueError, not
  AttributeError, on a closed SSL socket.  Patch by Senko Rasic.

- bpo-18513: Fix behaviour of cmath.rect w.r.t. signed zeros on OS X 10.8 +

- bpo-18479: Changed venv Activate.ps1 to make deactivate a function, and
  removed Deactivate.ps1.

- bpo-18480: Add missing call to PyType_Ready to the _elementtree extension.

- bpo-17778: Fix test discovery for test_multiprocessing. (Patch by Zachary

- bpo-18393: The private module _gestalt and private functions
  platform._mac_ver_gestalt, platform._mac_ver_lookup and platform._bcd2str
  have been removed. This does not affect the public interface of the
  platform module.

- bpo-17482: functools.update_wrapper (and functools.wraps) now set the
  __wrapped__ attribute correctly even if the underlying function has a
  __wrapped__ attribute set.

- bpo-18431: The new email header parser now decodes RFC2047 encoded words
  in structured headers.

- bpo-18432: The sched module's queue method was incorrectly returning an
  iterator instead of a list.

- bpo-18044: The new email header parser was mis-parsing encoded words where
  an encoded character immediately followed the '?' that follows the CTE
  character, resulting in a decoding failure.  They are now decoded

- bpo-18101: Tcl.split() now process strings nested in a tuple as it do with
  byte strings.

- bpo-18116: getpass was always getting an error when testing /dev/tty, and
  thus was always falling back to stdin, and would then raise an exception
  if stdin could not be used (such as /dev/null).  It also leaked an open
  file. All of these issues are now fixed.

- bpo-17198: Fix a NameError in the dbm module.  Patch by Valentina

- bpo-18013: Fix cgi.FieldStorage to parse the W3C sample form.

- bpo-18020: improve html.escape speed by an order of magnitude. Patch by
  Matt Bryant.

- bpo-18347: ElementTree's html serializer now preserves the case of closing

- bpo-17261: Ensure multiprocessing's proxies use proper address.

- bpo-18343: faulthandler.register() now keeps the previous signal handler
  when the function is called twice, so faulthandler.unregister() restores
  correctly the original signal handler.

- bpo-17097: Make multiprocessing ignore EINTR.

- bpo-18339: Negative ints keys in unpickler.memo dict no longer cause a
  segfault inside the _pickle C extension.

- bpo-18240: The HMAC module is no longer restricted to bytes and accepts
  any bytes-like object, e.g. memoryview. Original patch by Jonas Borgström.

- bpo-18224: Removed pydoc script from created venv, as it causes problems
  on Windows and adds no value over and above python -m pydoc ...

- bpo-18155: The csv module now correctly handles csv files that use a
  delimiter character that has a special meaning in regexes, instead of
  throwing an exception.

- bpo-14360: encode_quopri can now be successfully used as an encoder when
  constructing a MIMEApplication object.

- bpo-11390: Add -o and -f command line options to the doctest CLI to
  specify doctest options (and convert it to using argparse).

- bpo-18135: ssl.SSLSocket.write() now raises an OverflowError if the input
  string in longer than 2 gigabytes, and ssl.SSLContext.load_cert_chain()
  raises a ValueError if the password is longer than 2 gigabytes. The ssl
  module does not support partial write.

- bpo-11016: Add C implementation of the stat module as _stat.

- bpo-18248: Fix libffi build on AIX.

- bpo-18259: Declare sethostname in socketmodule.c for AIX

- bpo-18147: Add diagnostic functions to ssl.SSLContext(). get_ca_list()
  lists all loaded CA certificates and cert_store_stats() returns amount of
  loaded X.509 certs, X.509 CA certs and CRLs.

- bpo-18167: cgi.FieldStorage no longer fails to handle multipart/form-data
  when ``\r\n`` appears at end of 65535 bytes without other newlines.

- bpo-18076: Introduce importlib.util.decode_source().

- bpo-18357: add tests for dictview set difference. Patch by Fraser

- no longer changes SyntaxError or
  UnicodeDecodeError into ImportError.

- bpo-18058: Make the namespace package loader meet the ABC, allowing for namespace packages to work
  with runpy. (See also: bpo-18057)

- bpo-17177: The imp module is pending deprecation.

- subprocess: Prevent a possible double close of parent pipe fds when the
  subprocess exec runs into an error.  Prevent a regular multi-close of the
  /dev/null fd when any of stdin, stdout and stderr was set to DEVNULL.

- bpo-18194: Introduce importlib.util.cache_from_source() and
  source_from_cache() while documenting the equivalent functions in imp as

- bpo-17907: Document imp.new_module() as deprecated in favour of

- bpo-18192: Introduce importlib.util.MAGIC_NUMBER and document as
  deprecated imp.get_magic().

- bpo-18149: Add filecmp.clear_cache() to manually clear the filecmp cache.
  Patch by Mark Levitt

- bpo-18193: Add importlib.reload().

- bpo-18157: Stop using imp.load_module() in pydoc.

- bpo-16102: Make uuid._netbios_getnode() work again on Python 3.

- bpo-17134: Add ssl.enum_cert_store() as interface to Windows' cert store.

- bpo-18143: Implement ssl.get_default_verify_paths() in order to debug the
  default locations for cafile and capath.

- bpo-17314: Move multiprocessing.forking over to importlib.

- bpo-11959: SMTPServer and SMTPChannel now take an optional map, use of
  which avoids affecting global state.

- bpo-18109: os.uname() now decodes fields from the locale encoding, and
  socket.gethostname() now decodes the hostname from the locale encoding,
  instead of using the UTF-8 encoding in strict mode.

- bpo-18089: Implement

- bpo-18088: Introduce for setting
  module attributes. Leads to the pending deprecation of

- bpo-17403: urllib.parse.robotparser normalizes the urls before adding to
  ruleline. This helps in handling certain types invalid urls in a
  conservative manner. Patch contributed by Mher Movsisyan.

- bpo-18070: Have importlib.util.module_for_loader() set attributes
  unconditionally in order to properly support reloading.

- Added importlib.util.module_to_load to return a context manager to provide
  the proper module object to load.

- bpo-18025: Fixed a segfault in io.BufferedIOBase.readinto() when raw
  stream's read() returns more bytes than requested.

- bpo-18011: As was originally intended, base64.b32decode() now raises a
  binascii.Error if there are non-b32-alphabet characters present in the
  input string, instead of a TypeError.

- bpo-18072: Implement and

- bpo-8240: Set the SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER flag on SSL sockets.

- bpo-17269: Workaround for socket.getaddrinfo crash on MacOS X with port
  None or "0" and flags AI_NUMERICSERV.

- bpo-16986: ElementTree now correctly works with string input when the
  internal XML encoding is not UTF-8 or US-ASCII.

- bpo-17996: socket module now exposes AF_LINK constant on BSD and OSX.

- bpo-17900: Allowed pickling of recursive OrderedDicts.  Decreased pickled
  size and pickling time.

- bpo-17914: Add os.cpu_count(). Patch by Yogesh Chaudhari, based on an
  initial patch by Trent Nelson.

- bpo-17812: Fixed quadratic complexity of base64.b32encode(). Optimize
  base64.b32encode() and base64.b32decode() (speed up to 3x).

- bpo-17980: Fix possible abuse of ssl.match_hostname() for denial of
  service using certificates with many wildcards (CVE-2013-2099).

- bpo-15758: Fix FileIO.readall() so it no longer has O(n**2) complexity.

- bpo-14596: The struct.Struct() objects now use a more compact

- bpo-17981: logging's SysLogHandler now closes the socket when it catches
  socket OSErrors.

- bpo-17964: Fix os.sysconf(): the return type of the C sysconf() function
  is long, not int.

- Fix typos in the multiprocessing module.

- bpo-17754: Make ctypes.util.find_library() independent of the locale.

- bpo-17968: Fix memory leak in os.listxattr().

- bpo-17606: Fixed support of encoded byte strings in the XMLGenerator
  characters() and ignorableWhitespace() methods.  Original patch by
  Sebastian Ortiz Vasquez.

- bpo-17732: Ignore distutils.cfg options pertaining to install paths if a
  virtual environment is active.

- bpo-17915: Fix interoperability of xml.sax with file objects returned by

- bpo-16601: Restarting iteration over tarfile really restarts rather than
  continuing from where it left off.  Patch by Michael Birtwell.

- bpo-17289: The readline module now plays nicer with external modules or
  applications changing the rl_completer_word_break_characters global
  variable.  Initial patch by Bradley Froehle.

- bpo-12181: select module: Fix struct kevent definition on OpenBSD 64-bit
  platforms. Patch by Federico Schwindt.

- bpo-11816: multiple improvements to the dis module: get_instructions
  generator, ability to redirect output to a file, Bytecode and Instruction
  abstractions. Patch by Nick Coghlan, Ryan Kelly and Thomas Kluyver.

- bpo-13831: Embed stringification of remote traceback in local traceback
  raised when pool task raises an exception.

- bpo-15528: Add weakref.finalize to support finalization using weakref

- bpo-14173: Avoid crashing when reading a signal handler during interpreter

- bpo-15902: Fix imp.load_module() accepting None as a file when loading an
  extension module.

- bpo-13721: SSLSocket.getpeercert() and SSLSocket.do_handshake() now raise
  an OSError with ENOTCONN, instead of an AttributeError, when the SSLSocket
  is not connected.

- bpo-14679: add an __all__ (that contains only HTMLParser) to html.parser.

- bpo-17802: Fix an UnboundLocalError in html.parser.  Initial tests by
  Thomas Barlow.

- bpo-17358: Modules loaded by imp.load_source() and load_compiled() (and by
  extension load_module()) now have a better chance of working when

- bpo-17804: New function ``struct.iter_unpack`` allows for streaming struct

- bpo-17830: When is used to update a keyword file, it now
  preserves the line endings of the original file.

- bpo-17272: Making the urllib.request's Request.full_url a descriptor.
  Fixes bugs with assignment to full_url. Patch by Demian Brecht.

- bpo-17353: Plistlib emitted empty data tags with deeply nested

- bpo-11714: Use 'with' statements to assure a Semaphore releases a
  condition variable. Original patch by Thomas Rachel.

- bpo-16624: `subprocess.check_output` now accepts an `input` argument,
  allowing the subprocess's stdin to be provided as a (byte) string. Patch
  by Zack Weinberg.

- bpo-17795: Reverted backwards-incompatible change in SysLogHandler with
  Unix domain sockets.

- bpo-16694: Add a pure Python implementation of the operator module. Patch
  by Zachary Ware.

- bpo-11182: remove the unused and undocumented pydoc.Scanner class. Patch
  by Martin Morrison.

- bpo-17741: Add ElementTree.XMLPullParser, an event-driven parser for non-
  blocking applications.

- bpo-17555: Fix ForkAwareThreadLock so that size of after fork registry
  does not grow exponentially with generation of process.

- bpo-17707: fix regression in multiprocessing.Queue's get() method where it
  did not block for short timeouts.

- bpo-17720: Fix the Python implementation of pickle.Unpickler to correctly
  process the APPENDS opcode when it is used on non-list objects.

- bpo-17012: shutil.which() no longer falls back to the PATH environment
  variable if an empty path argument is specified.  Patch by Serhiy

- bpo-17710: Fix pickle raising a SystemError on bogus input.

- bpo-17341: Include the invalid name in the error messages from re about
  invalid group names.

- bpo-17702: os.environ now raises KeyError with the original environment
  variable name (str on UNIX), instead of using the encoded name (bytes on

- bpo-16163: Make the importlib based version of pkgutil.iter_importers work
  for submodules. Initial patch by Berker Peksag.

- bpo-16804: Fix a bug in the 'site' module that caused running 'python -S
  -m site' to incorrectly throw an exception.

- bpo-15480: Remove the deprecated and unused TYPE_INT64 code from marshal.
  Initial patch by Daniel Riti.

- bpo-2118: SMTPException is now a subclass of OSError.

- bpo-17016: Get rid of possible pointer wraparounds and integer overflows
  in the re module.  Patch by Nickolai Zeldovich.

- bpo-16658: add missing return to HTTPConnection.send(). Patch by Jeff

- bpo-9556: the logging package now allows specifying a time-of-day for a
  TimedRotatingFileHandler to rotate.

- bpo-14971: unittest test discovery no longer gets confused when a function
  has a different __name__ than its name in the TestCase class dictionary.

- bpo-17487: The wave getparams method now returns a namedtuple rather than
  a plain tuple.

- bpo-17675: socket repr() provides local and remote addresses (if any).
  Patch by Giampaolo Rodola'

- bpo-17093: Make the ABCs in provide default values or raise
  reasonable exceptions for their methods to make them more amenable to
  super() calls.

- bpo-17566: Make optional instead of an
  abstractmethod; now it raises NotImplementedError so as to be ignored by

- bpo-17678: Remove the use of deprecated method in http/ by
  changing the call to get_origin_req_host() to origin_req_host.

- bpo-17666: Fix reading gzip files with an extra field.

- bpo-16475: Support object instancing, recursion and interned strings in

- bpo-17502: Process DEFAULT values in mock side_effect that returns

- bpo-16795: On the ast.arguments object, unify vararg with varargannotation
  and kwarg and kwargannotation. Change the column offset of ast.Attribute
  to be at the attribute name.

- bpo-17434: Properly raise a SyntaxError when a string occurs between
  future imports.

- bpo-17117: Import and @importlib.util.set_loader now set __loader__ when
  it has a value of None or the attribute doesn't exist.

- bpo-17032: The "global" in the "NameError: global name 'x' is not defined"
  error message has been removed.  Patch by Ram Rachum.

- bpo-18080: When building a C extension module on OS X, if the compiler is
  overridden with the CC environment variable, use the new compiler as the
  default for linking if LDSHARED is not also overridden.  This restores
  Distutils behavior introduced in 3.2.3 and inadvertently dropped in 3.3.0.

- bpo-18113: Fixed a refcount leak in the curses.panel module's
  set_userptr() method. Reported by Atsuo Ishimoto.

- Implement PEP 443 "Single-dispatch generic functions".

- Implement PEP 435 "Adding an Enum type to the Python standard library".

- bpo-15596: Faster pickling of unicode strings.

- bpo-17572: Avoid chained exceptions when passing bad directives to
  time.strptime(). Initial patch by Claudiu Popa.

- bpo-17435: threading.Timer's __init__ method no longer uses mutable
  default values for the args and kwargs parameters.

- bpo-17526: fix an IndexError raised while passing code without filename to
  inspect.findsource().  Initial patch by Tyler Doyle.

- bpo-17540: Added style parameter to logging formatter configuration by

- bpo-16692: The ssl module now supports TLS 1.1 and TLS 1.2.  Initial patch
  by Michele Orrù.

- bpo-17025: multiprocessing: Reduce Queue and SimpleQueue contention.

- bpo-17536: Add to webbrowser's browser list: www-browser, x-www-browser,
  iceweasel, iceape.

- bpo-17150: pprint now uses line continuations to wrap long string

- bpo-17488: Change the subprocess.Popen bufsize parameter default value
  from unbuffered (0) to buffering (-1) to match the behavior existing code
  expects and match the behavior of the subprocess module in Python 2 to
  avoid introducing hard to track down bugs.

- bpo-17521: Corrected non-enabling of logger following two calls to

- bpo-17508: Corrected logging MemoryHandler configuration in dictConfig()
  where the target handler wasn't configured first.

- bpo-17209: curses.window.get_wch() now correctly handles KeyboardInterrupt

- bpo-5713: smtplib now handles 421 (closing connection) error codes when
  sending mail by closing the socket and reporting the 421 error code via
  the exception appropriate to the command that received the error response.

- bpo-16997: unittest.TestCase now provides a subTest() context manager to
  procedurally generate, in an easy way, small test instances.

- bpo-17485: Also delete the Request Content-Length header if the data
  attribute is deleted.  (Follow on to issue Issue #16464).

- bpo-15927: CVS now correctly parses escaped newlines and carriage when
  parsing with quoting turned off.

- bpo-17467: add readline and readlines support to mock_open in

- bpo-13248: removed deprecated and undocumented difflib.isbjunk,

- bpo-17192: Update the ctypes module's libffi to v3.0.13.  This
  specifically addresses a stack misalignment issue on x86 and issues on
  some more recent platforms.

- bpo-8862: Fixed curses cleanup when getkey is interrupted by a signal.

- bpo-17443: imaplib.IMAP4_stream was using the default unbuffered IO in
  subprocess, but the imap code assumes buffered IO.  In Python2 this worked
  by accident. IMAP4_stream now explicitly uses buffered IO.

- bpo-17476: Fixed regression relative to Python2 in undocumented pydoc
  'allmethods'; it was missing unbound methods on the class.

- bpo-17474: Remove the deprecated methods of Request class.

- bpo-16709: unittest discover order is no-longer filesystem specific. Patch
  by Jeff Ramnani.

- Use the HTTPS PyPI url for upload, overriding any plain HTTP URL in

- bpo-5024: sndhdr.whichhdr now returns the frame count for WAV files rather
  than -1.

- bpo-17460: Remove the strict argument of HTTPConnection and removing the
  DeprecationWarning being issued from 3.2 onwards.

- bpo-16880: Do not assume _imp.load_dynamic() is defined in the imp module.

- bpo-16389: Fixed a performance regression relative to Python 3.1 in the
  caching of compiled regular expressions.

- Added missing FeedParser and BytesFeedParser to email.parser.__all__.

- bpo-17431: Fix missing import of BytesFeedParser in email.parser.

- bpo-12921: http.server's send_error takes an explain argument to send more
  information in response. Patch contributed by Karl.

- bpo-17414: Add timeit, repeat, and default_timer to timeit.__all__.

- bpo-1285086: Get rid of the refcounting hack and speed up
  urllib.parse.unquote() and urllib.parse.unquote_to_bytes().

- bpo-17099: Have importlib.find_loader() raise ValueError when __loader__
  is not set, harmonizing with what happens when the attribute is set to

- Expose the O_PATH constant in the os module if it is available.

- bpo-17368: Fix an off-by-one error in the Python JSON decoder that caused
  a failure while decoding empty object literals when object_pairs_hook was

- bpo-17385: Fix quadratic behavior in threading.Condition.  The FIFO queue
  now uses a deque instead of a list.

- bpo-15806: Add contextlib.ignore().  This creates a context manager to
  ignore specified exceptions, replacing the "except SomeException: pass"

- bpo-14645: The email generator classes now produce output using the
  specified linesep throughout.  Previously if the prolog, epilog, or body
  were stored with a different linesep, that linesep was used.  This fix
  corrects an RFC non- compliance issue with smtplib.send_message.

- bpo-17278: Fix a crash in heapq.heappush() and heapq.heappop() when the
  list is being resized concurrently.

- bpo-16962: Use getdents64 instead of the obsolete getdents syscall in the
  subprocess module on Linux.

- bpo-16935: unittest now counts the module as skipped if it raises
  SkipTest, instead of counting it as an error.  Patch by Zachary Ware.

- bpo-17018: Make Process.join() retry if os.waitpid() fails with EINTR.

- bpo-17223: array module: Fix a crasher when converting an array containing
  invalid characters (outside range [U+0000; U+10ffff]) to Unicode:
  repr(array), str(array) and array.tounicode(). Patch written by Manuel

- bpo-17197: profile/cProfile modules refactored so that code of run() and
  runctx() utility functions is not duplicated in both modules.

- bpo-14720: sqlite3: Convert datetime microseconds correctly. Patch by Lowe

- bpo-15132: Allow a list for the defaultTest argument of
  unittest.TestProgram. Patch by Jyrki Pulliainen.

- bpo-17225: JSON decoder now counts columns in the first line starting with
  1, as in other lines.

- bpo-6623: Added explicit DeprecationWarning for ftplib.netrc, which has
  been deprecated and undocumented for a long time.

- bpo-13700: Fix byte/string handling in imaplib authentication when an
  authobject is specified.

- bpo-13153: Tkinter functions now raise TclError instead of ValueError when
  a string argument contains non-BMP character.

- bpo-9669: Protect re against infinite loops on zero-width matching in non-
  greedy repeat.  Patch by Matthew Barnett.

- bpo-13169: The maximal repetition number in a regular expression has been
  increased from 65534 to 2147483647 (on 32-bit platform) or 4294967294 (on

- bpo-17143: Fix a missing import in the trace module.  Initial patch by
  Berker Peksag.

- bpo-15220: email.feedparser's line splitting algorithm is now simpler and

- bpo-16743: Fix mmap overflow check on 32 bit Windows.

- bpo-16996: webbrowser module now uses shutil.which() to find a web-browser
  on the executable search path.

- bpo-16800: tempfile.gettempdir() no longer left temporary files when the
  disk is full. Original patch by Amir Szekely.

- bpo-17192: Import libffi-3.0.12.

- bpo-16564: Fixed regression relative to Python2 in the operation of
  email.encoders.encode_7or8bit when used with binary data.

- bpo-17052: unittest discovery should use self.testLoader.

- bpo-4591: Uid and gid values larger than 2**31 are supported now.

- bpo-17141: random.vonmisesvariate() no longer hangs for large kappas.

- bpo-17149: Fix random.vonmisesvariate to always return results in [0,

- bpo-1470548: XMLGenerator now works with binary output streams.

- bpo-6975: os.path.realpath() now correctly resolves multiple nested
  symlinks on POSIX platforms.

- bpo-13773: sqlite3.connect() gets a new `uri` parameter to pass the
  filename as a URI, allowing custom options to be passed.

- bpo-16564: Fixed regression relative to Python2 in the operation of
  email.encoders.encode_noop when used with binary data.

- bpo-10355: The mode, name, encoding and newlines properties now work on
  SpooledTemporaryFile objects even when they have not yet rolled over.
  Obsolete method xreadline (which has never worked in Python 3) has been

- bpo-16686: Fixed a lot of bugs in audioop module.  Fixed crashes in
  avgpp(), maxpp() and ratecv().  Fixed an integer overflow in add(),
  bias(), and ratecv(). reverse(), lin2lin() and ratecv() no more lose
  precision for 32-bit samples. max() and rms() no more returns a negative
  result and various other functions now work correctly with 32-bit sample

- bpo-17073: Fix some integer overflows in sqlite3 module.

- bpo-16723: httplib.HTTPResponse no longer marked closed when the
  connection is automatically closed.

- bpo-15359: Add CAN_BCM protocol support to the socket module. Patch by
  Brian Thorne.

- bpo-16948: Fix quoted printable body encoding for non-latin1 character
  sets in the email package.

- bpo-16811: Fix folding of headers with no value in the provisional email

- bpo-17132: Update symbol for "yield from" grammar changes.

- bpo-17076: Make copying of xattrs more tolerant of missing FS support.
  Patch by Thomas Wouters.

- bpo-17089: Expat parser now correctly works with string input when the
  internal XML encoding is not UTF-8 or US-ASCII.  It also now accepts bytes
  and strings larger than 2 GiB.

- bpo-6083: Fix multiple segmentation faults occurred when PyArg_ParseTuple
  parses nested mutating sequence.

- bpo-5289: Fix ctypes.util.find_library on Solaris.

- bpo-17106: Fix a segmentation fault in io.TextIOWrapper when an underlying
  stream or a decoder produces data of an unexpected type (i.e. when
  io.TextIOWrapper initialized with text stream or use bytes-to-bytes

- bpo-17015: When it has a spec, a Mock object now inspects its signature
  when matching calls, so that arguments can be matched positionally or by

- bpo-15633: httplib.HTTPResponse is now mark closed when the server sends
  less than the advertised Content-Length.

- bpo-12268: The io module file object write methods no longer abort early
  when one of its write system calls is interrupted (EINTR).

- bpo-6972: The zipfile module no longer overwrites files outside of its
  destination path when extracting malicious zip files.

- bpo-4844: ZipFile now raises BadZipFile when opens a ZIP file with an
  incomplete "End of Central Directory" record.  Original patch by Guilherme
  Polo and Alan McIntyre.

- bpo-17071: Signature.bind() now works when one of the keyword arguments is
  named ``self``.

- bpo-12004: Fix an internal error in PyZipFile when writing an invalid
  Python file. Patch by Ben Morgan.

- Have py_compile use importlib as much as possible to avoid code
  duplication. Code now raises FileExistsError if the file path to be used
  for the byte- compiled file is a symlink or non-regular file as a warning
  that import will not keep the file path type if it writes to that path.

- bpo-16972: Have site.addpackage() consider already known paths even when
  none are explicitly passed in. Bug report and fix by Kirill.

- bpo-1602133: on Mac OS X a shared library build (``--enable-shared``) now
  fills the ``os.environ`` variable correctly.

- bpo-15505: `unittest.installHandler` no longer assumes SIGINT handler is
  set to a callable object.

- bpo-13454: Fix a crash when deleting an iterator created by
  itertools.tee() if all other iterators were very advanced before.

- bpo-12411: Fix to cgi.parse_multipart to correctly use bytes boundaries
  and bytes data. Patch by Jonas Wagner.

- bpo-16957: shutil.which() no longer searches a bare file name in the
  current directory on Unix and no longer searches a relative file path with
  a directory part in PATH directories.  Patch by Thomas Kluyver.

- bpo-1159051: GzipFile now raises EOFError when reading a corrupted file
  with truncated header or footer.

- bpo-16993: shutil.which() now preserves the case of the path and extension
  on Windows.

- bpo-16992: On Windows in signal.set_wakeup_fd, validate the file
  descriptor argument.

- bpo-16422: For compatibility with the Python version, the C version of
  decimal now uses strings instead of integers for rounding mode constants.

- bpo-15861: tkinter now correctly works with lists and tuples containing
  strings with whitespaces, backslashes or unbalanced braces.

- bpo-9720: zipfile now writes correct local headers for files larger than 4

- bpo-16955: Fix the poll() method for multiprocessing's socket connections
  on Windows.

- SSLContext.load_dh_params() now properly closes the input file.

- bpo-15031: Refactor some .pyc management code to cut down on code
  duplication. Thanks to Ronan Lamy for the report and taking an initial
  stab at the problem.

- bpo-16398: Optimize deque.rotate() so that it only moves pointers and
  doesn't touch the underlying data with increfs and decrefs.

- bpo-16900: Issue a ResourceWarning when an ssl socket is left unclosed.

- bpo-13899: ``\A``, ``\Z``, and ``\B`` now correctly match the A, Z, and B
  literals when used inside character classes (e.g. ``'[\A]'``). Patch by
  Matthew Barnett.

- bpo-15545: Fix regression in sqlite3's iterdump method where it was
  failing if the connection used a row factory (such as sqlite3.Row) that
  produced unsortable objects. (Regression was introduced by fix for 9750).

- fcntl: add F_DUPFD_CLOEXEC constant, available on Linux 2.6.24+.

- bpo-15972: Fix error messages when os functions expecting a file name or
  file descriptor receive the incorrect type.

- bpo-8109: The ssl module now has support for server-side SNI, thanks to a
  :meth:`SSLContext.set_servername_callback` method.  Patch by Daniel Black.

- bpo-16860: In tempfile, use O_CLOEXEC when available to set the close-on-
  exec flag atomically.

- bpo-16674: random.getrandbits() is now 20-40% faster for small integers.

- bpo-16009: JSON error messages now provide more information.

- bpo-16828: Fix error incorrectly raised by bz2.compress(b'') and
  bz2.BZ2Compressor.compress(b''). Initial patch by Martin Packman.

- bpo-16833: In http.client.HTTPConnection, do not concatenate the request
  headers and body when the payload exceeds 16 KB, since it can consume more
  memory for no benefit.  Patch by Benno Leslie.

- bpo-16541: tk_setPalette() now works with keyword arguments.

- bpo-16820: In configparser, `parser.popitem()` no longer raises
  ValueError. This makes `parser.clean()` work correctly.

- bpo-16820: In configparser, ``parser['section'] = {}`` now preserves
  section order within the parser. This makes `parser.update()` preserve
  section order as well.

- bpo-16820: In configparser, ``parser['DEFAULT'] = {}`` now correctly
  clears previous values stored in the default section. Same goes for
  ``parser.update({'DEFAULT': {}})``.

- bpo-9586: Redefine SEM_FAILED on MacOSX to keep compiler happy.

- bpo-16787: Increase asyncore and asynchat default output buffers size, to
  decrease CPU usage and increase throughput.

- bpo-10527: make multiprocessing use poll() instead of select() if

- bpo-16688: Now regexes contained backreferences correctly work with non-
  ASCII strings. Patch by Matthew Barnett.

- bpo-16486: Make aifc files act as context managers.

- bpo-16485: Now file descriptors are closed if file header patching failed
  on closing an aifc file.

- bpo-16640: Run less code under a lock in sched module.

- bpo-16165: no longer blocks a scheduler for other

- bpo-16641: Default values of sched.scheduler.enter() are no longer

- bpo-16618: Make glob.glob match consistently across strings and bytes
  regarding leading dots.  Patch by Serhiy Storchaka.

- bpo-16788: Add samestat to Lib/

- bpo-16713: Parsing of 'tel' urls using urlparse separates params from

- bpo-16443: Add docstrings to regular expression match objects. Patch by
  Anton Kasyanov.

- bpo-15701: Fix HTTPError info method call to return the headers

- bpo-16752: Add a missing import to modulefinder. Patch by Berker Peksag.

- bpo-16646: ftplib.FTP.makeport() might lose socket error details. (patch
  by Serhiy Storchaka)

- bpo-16626: Fix infinite recursion in glob.glob() on Windows when the
  pattern contains a wildcard in the drive or UNC path.  Patch by Serhiy

- bpo-15783: Except for the number methods, the C version of decimal now
  supports all None default values present in These values were
  largely undocumented.

- bpo-11175: argparse.FileType now accepts encoding and errors arguments.
  Patch by Lucas Maystre.

- bpo-16488: epoll() objects now support the `with` statement.  Patch by
  Serhiy Storchaka.

- bpo-16298: In, close the socket when there is no
  Content-Length and the incoming stream is finished.  Patch by Eran

- bpo-16049: Add abc.ABC class to enable the use of inheritance to create
  ABCs, rather than the more cumbersome metaclass=ABCMeta. Patch by Bruno

- Expose the TCP_FASTOPEN and MSG_FASTOPEN flags in socket when they're

- bpo-15701: Add a .headers attribute to urllib.error.HTTPError. Patch
  contributed by Berker Peksag.

- bpo-15872: Fix 3.3 regression introduced by the new fd-based shutil.rmtree
  that caused it to not ignore certain errors when ignore_errors was set.
  Patch by Alessandro Moura and Serhiy Storchaka.

- bpo-16248: Disable code execution from the user's home directory by
  tkinter when the -E flag is passed to Python.  Patch by Zachary Ware.

- bpo-13390: New function :func:`sys.getallocatedblocks()` returns the
  number of memory blocks currently allocated.

- bpo-16628: Fix a memory leak in ctypes.resize().

- bpo-13614: Fix register failure with invalid rst in description.
  Patch by Julien Courteau and Pierre Paul Lefebvre.

- bpo-13512: Create ~/.pypirc securely (CVE-2011-4944).  Initial patch by
  Philip Jenvey, tested by Mageia and Debian.

- bpo-7719: Make distutils ignore ``.nfs*`` files instead of choking later
  on.  Initial patch by SilentGhost and Jeff Ramnani.

- bpo-13120: Allow calling pdb.set_trace() from thread. Patch by Ilya

- bpo-16585: Make CJK encoders support error handlers that return bytes per
  PEP 383.

- bpo-10182: The re module doesn't truncate indices to 32 bits anymore.
  Patch by Serhiy Storchaka.

- bpo-16333: use (",", ": ") as default separator in json when indent is
  specified, to avoid trailing whitespace.  Patch by Serhiy Storchaka.

- bpo-16573: In 2to3, treat enumerate() like a consuming call, so
  superfluous list() calls aren't added to filter(), map(), and zip() which
  are directly passed enumerate().

- bpo-16464: Reset the Content-Length header when a urllib Request is reused
  with new data.

- bpo-12848: The pure Python pickle implementation now treats object lengths
  as unsigned 32-bit integers, like the C implementation does. Patch by
  Serhiy Storchaka.

- bpo-16423: urllib.request now has support for ``data:`` URLs.  Patch by
  Mathias Panzenböck.

- bpo-4473: Add a POP3.stls() to switch a clear-text POP3 session into an
  encrypted POP3 session, on supported servers.  Patch by Lorenzo Catucci.

- bpo-4473: Add a POP3.capa() method to query the capabilities advertised by
  the POP3 server.  Patch by Lorenzo Catucci.

- bpo-4473: Ensure the socket is shutdown cleanly in POP3.close(). Patch by
  Lorenzo Catucci.

- bpo-16522: added FAIL_FAST flag to doctest.

- bpo-15627: Add the method.

- bpo-16408: Fix file descriptors not being closed in error conditions in
  the zipfile module.  Patch by Serhiy Storchaka.

- bpo-14631: Add a new :class:`weakref.WeakMethod` to simulate weak
  references to bound methods.

- bpo-16469: Fix exceptions from float -> Fraction and Decimal -> Fraction
  conversions for special values to be consistent with those for float ->
  int and Decimal -> int.  Patch by Alexey Kachayev.

- bpo-16481: multiprocessing no longer leaks process handles on Windows.

- bpo-12428: Add a pure Python implementation of functools.partial(). Patch
  by Brian Thorne.

- bpo-16140: The subprocess module no longer double closes its child
  subprocess.PIPE parent file descriptors on child error prior to exec().

- Remove a bare print to stdout from the subprocess module that could have
  happened if the child process wrote garbage to its pre-exec error pipe.

- The subprocess module now raises its own SubprocessError instead of a
  RuntimeError in various error situations which should not normally happen.

- bpo-16327: The subprocess module no longer leaks file descriptors used for
  stdin/stdout/stderr pipes to the child when fork() fails.

- bpo-14396: Handle the odd rare case of waitpid returning 0 when not
  expected in subprocess.Popen.wait().

- bpo-16411: Fix a bug where zlib.decompressobj().flush() might try to
  access previously- freed memory. Patch by Serhiy Storchaka.

- bpo-16357: fix calling accept() on a SSLSocket created through
  SSLContext.wrap_socket().  Original patch by Jeff McNeil.

- bpo-16409: The reporthook callback made by the legacy
  urllib.request.urlretrieve API now properly supplies a constant non-zero
  block_size as it did in Python 3.2 and 2.7.  This matches the behavior of

- bpo-16431: Use the type information when constructing a Decimal subtype
  from a Decimal argument.

- bpo-15641: Clean up deprecated classes from importlib. Patch by Taras

- bpo-16350: zlib.decompressobj().decompress() now accumulates data from
  successive calls after EOF in unused_data, instead of only saving the
  argument to the last call. decompressobj().flush() now correctly sets
  unused_data and unconsumed_tail. A bug in the handling of MemoryError when
  setting the unconsumed_tail attribute has also been fixed. Patch by Serhiy

- bpo-12759: sre_parse now raises a proper error when the name of the group
  is missing. Initial patch by Serhiy Storchaka.

- bpo-16152: fix tokenize to ignore whitespace at the end of the code when
  no newline is found.  Patch by Ned Batchelder.

- bpo-16284: Prevent keeping unnecessary references to worker functions in
  concurrent.futures ThreadPoolExecutor.

- bpo-16230: Fix a crash in when one of the lists changes
  size while iterated on.  Patch by Serhiy Storchaka.

- bpo-16228: Fix a crash in the json module where a list changes size while
  it is being encoded.  Patch by Serhiy Storchaka.

- bpo-16351: New function gc.get_stats() returns per-generation collection

- bpo-14897: Enhance error messages of struct.pack and struct.pack_into.
  Patch by Matti Mäki.

- bpo-16316: mimetypes now recognizes the .xz and .txz (.tar.xz) extensions.
  Patch by Serhiy Storchaka.

- bpo-12890: cgitb no longer prints spurious 

tags in text mode when the logdir option is specified. - bpo-16307: Fix multiprocessing.Pool.map_async not calling its callbacks. Patch by Janne Karila. - bpo-16305: Fix a segmentation fault occurring when interrupting math.factorial. - bpo-16116: Fix include and library paths to be correct when building C extensions in venvs. - bpo-16245: Fix the value of a few entities in html.entities.html5. - bpo-16301: Fix the localhost verification in urllib/ for ``file://`` urls. - bpo-16250: Fix the invocations of URLError which had misplaced filename attribute for exception. - bpo-10836: Fix exception raised when file not found in urlretrieve Initial patch by Ezio Melotti. - bpo-14398: Fix size truncation and overflow bugs in the bz2 module. - bpo-12692: Fix resource leak in urllib.request when talking to an HTTP server that does not include a ``Connection: close`` header in its responses. - bpo-12034: Fix bogus caching of result in check_GetFinalPathNameByHandle. Patch by Atsuo Ishimoto. - Improve performance of `lzma.LZMAFile` (see also issue #16034). - bpo-16220: wsgiref now always calls close() on an iterable response. Patch by Brent Tubbs. - bpo-16270: urllib may hang when used for retrieving files via FTP by using a context manager. Patch by Giampaolo Rodola'. - bpo-16461: Wave library should be able to deal with 4GB wav files, and sample rate of 44100 Hz. - bpo-16176: Properly identify Windows 8 via platform.platform() - bpo-16088: BaseHTTPRequestHandler's send_error method includes a Content- Length header in its response now. Patch by Antoine Pitrou. - bpo-16114: The subprocess module no longer provides a misleading error message stating that args[0] did not exist when either the cwd or executable keyword arguments specified a path that did not exist. - bpo-16169: Fix ctypes.WinError()'s confusion between errno and winerror. - bpo-16110: logging.fileConfig now accepts a pre-initialised ConfigParser instance. - bpo-1492704: shutil.copyfile() raises a distinct SameFileError now if source and destination are the same file. Patch by Atsuo Ishimoto. - bpo-13896: Make shelf instances work with 'with' as context managers. Original patch by Filip Gruszczyński. - bpo-15417: Add support for csh and fish in venv activation scripts. - bpo-14377: ElementTree.write and some of the module-level functions have a new parameter - *short_empty_elements*. It controls how elements with no contents are emitted. - bpo-16089: Allow ElementTree.TreeBuilder to work again with a non-Element element_factory (fixes a regression in SimpleTAL). - bpo-9650: List commonly used format codes in time.strftime and time.strptime docsttings. Original patch by Mike Hoy. - bpo-15452: logging configuration socket listener now has a verify option that allows an application to apply a verification function to the received configuration data before it is acted upon. - bpo-16034: Fix performance regressions in the new `bz2.BZ2File` implementation. Initial patch by Serhiy Storchaka. - `pty.spawn()` now returns the child process status returned by `os.waitpid()`. - bpo-15756: `subprocess.poll()` now properly handles `errno.ECHILD` to return a returncode of 0 when the child has already exited or cannot be waited on. - bpo-15323: Improve failure message of `Mock.assert_called_once_with()`. - bpo-16064: ``unittest -m`` claims executable is "python", not "python3". - bpo-12376: Pass on parameters in `TextTestResult.__init__()` super call. - bpo-15222: Insert blank line after each message in mbox mailboxes. - bpo-16013: Fix `csv.Reader` parsing issue with ending quote characters. Patch by Serhiy Storchaka. - bpo-15421: Fix an OverflowError in `Calendar.itermonthdates()` after `datetime.MAXYEAR`. Patch by Cédric Krier. - bpo-16112: platform.architecture does not correctly escape argument to /usr/bin/file. Patch by David Benjamin. - bpo-15970: `xml.etree.ElementTree` now serializes correctly the empty HTML elements 'meta' and 'param'. - bpo-15842: The `SocketIO.{readable,writable,seekable}` methods now raise ValueError when the file-like object is closed. Patch by Alessandro Moura. - bpo-15876: Fix a refleak in the `curses` module: window.encoding. - bpo-15881: Fix `atexit` hook in `multiprocessing`. Original patch by Chris McDonough. - bpo-15841: The readable(), writable() and seekable() methods of `io.BytesIO` and `io.StringIO` objects now raise ValueError when the object has been closed. Patch by Alessandro Moura. - bpo-15447: Use `subprocess.DEVNULL` in webbrowser, instead of opening `os.devnull` explicitly and leaving it open. - bpo-15509: `webbrowser.UnixBrowser` no longer passes empty arguments to Popen when ``%action`` substitutions produce empty strings. - bpo-12776: Call `argparse` type function (specified by add_argument) only once. Before, the type function was called twice in the case where the default was specified and the argument was given as well. This was especially problematic for the FileType type, as a default file would always be opened, even if a file argument was specified on the command line. (See also: bpo-11839) - bpo-15906: Fix a regression in argparse caused by the preceding change, when ``action='append'``, ``type='str'`` and ``default=[]``. - bpo-16113: Added sha3 module based on the Keccak reference implementation 3.2. The `hashlib` module has four additional hash algorithms: `sha3_224`, `sha3_256`, `sha3_384` and `sha3_512`. As part of the patch some common code was moved from _hashopenssl.c to hashlib.h. - ctypes.call_commethod was removed, since its only usage was in the defunct samples directory. - bpo-16692: Added TLSv1.1 and TLSv1.2 support for the ssl modules. - bpo-16832: add abc.get_cache_token() to expose cache validity checking support in ABCMeta. IDLE ---- - bpo-18429: Format / Format Paragraph, now works when comment blocks are selected. As with text blocks, this works best when the selection only includes complete lines. - bpo-18226: Add docstrings and unittests for Original patches by Todd Rovito and Phil Webster. - bpo-18279: Format - Strip trailing whitespace no longer marks a file as changed when it has not been changed. This fix followed the addition of a test file originally written by Phil Webster (the issue's main goal). - bpo-7136: In the Idle File menu, "New Window" is renamed "New File". Patch by Tal Einat, Roget Serwy, and Todd Rovito. - Remove dead imports of imp. - bpo-18196: Avoid displaying spurious SystemExit tracebacks. - bpo-5492: Avoid traceback when exiting IDLE caused by a race condition. - bpo-17511: Keep IDLE find dialog open after clicking "Find Next". Original patch by Sarah K. - bpo-18055: Move IDLE off of imp and on to importlib. - bpo-15392: Create a unittest framework for IDLE. Initial patch by Rajagopalasarma Jayakrishnan. See Lib/idlelib/idle_test/README.txt for how to run Idle tests. - bpo-14146: Highlight source line while debugging on Windows. - bpo-17838: Allow sys.stdin to be reassigned. - bpo-13495: Avoid loading the color delegator twice in IDLE. - bpo-17798: Allow IDLE to edit new files when specified on command line. - bpo-14735: Update IDLE docs to omit "Control-z on Windows". - bpo-17532: Always include Options menu for IDLE on OS X. Patch by Guilherme Simões. - bpo-17585: Fixed IDLE regression. Now closes when using exit() or quit(). - bpo-17657: Show full Tk version in IDLE's about dialog. Patch by Todd Rovito. - bpo-17613: Prevent traceback when removing syntax colorizer in IDLE. - bpo-1207589: Backwards-compatibility patch for right-click menu in IDLE. - bpo-16887: IDLE now accepts Cancel in tabify/untabify dialog box. - bpo-17625: In IDLE, close the replace dialog after it is used. - bpo-14254: IDLE now handles readline correctly across shell restarts. - bpo-17614: IDLE no longer raises exception when quickly closing a file. - bpo-6698: IDLE now opens just an editor window when configured to do so. - bpo-8900: Using keyboard shortcuts in IDLE to open a file no longer raises an exception. - bpo-6649: Fixed missing exit status in IDLE. Patch by Guilherme Polo. - bpo-17114: IDLE now uses non-strict config parser. - bpo-9290: In IDLE the sys.std* streams now implement io.TextIOBase interface and support all mandatory methods and properties. - bpo-5066: Update IDLE docs. Patch by Todd Rovito. - bpo-16829: IDLE printing no longer fails if there are spaces or other special characters in the file path. - bpo-16491: IDLE now prints chained exception tracebacks. - bpo-16819: IDLE method completion now correctly works for bytes literals. - bpo-16504: IDLE now catches SyntaxErrors raised by tokenizer. Patch by Roger Serwy. - bpo-16511: Use default IDLE width and height if config param is not valid. Patch Serhiy Storchaka. - bpo-1207589: Add Cut/Copy/Paste items to IDLE right click Context Menu. Patch by Todd Rovito. - bpo-16123: IDLE - deprecate running without a subprocess. Patch by Roger Serwy. Tests ----- - bpo-1666318: Add a test that shutil.copytree() retains directory permissions. Patch by Catherine Devlin. - bpo-18273: move the tests in Lib/test/json_tests to Lib/test/test_json and make them discoverable by unittest. Patch by Zachary Ware. - Fix a fcntl test case on KFreeBSD, Debian #708653 (Petr Salinger). - bpo-18396: Fix spurious test failure in test_signal on Windows when faulthandler is enabled (Patch by Jeremy Kloth) - bpo-17046: Fix broken test_executable_without_cwd in test_subprocess. - bpo-15415: Add new temp_dir() and change_cwd() context managers to, and refactor temp_cwd() to use them. Patch by Chris Jerdonek. - bpo-15494: is now a package rather than a module (Initial patch by Indra Talip) - bpo-17944: test_zipfile now discoverable and uses subclassing to generate tests for different compression types. Fixed a bug with skipping some tests due to use of exhausted iterators. - bpo-18266: test_largefile now works with unittest test discovery and supports running only selected tests. Patch by Zachary Ware. - bpo-17767: test_locale now works with unittest test discovery. Original patch by Zachary Ware. - bpo-18375: Assume --randomize when --randseed is used for running the testsuite. - bpo-11185: Fix test_wait4 under AIX. Patch by Sébastien Sablé. - bpo-18207: Fix test_ssl for some versions of OpenSSL that ignore seconds in ASN1_TIME fields. - bpo-18094: test_uuid no longer reports skipped tests as passed. - bpo-17992: Add timeouts to asyncore and asynchat tests so that they won't accidentally hang. - bpo-17833: Fix test_gdb failures seen on machines where debug symbols for glibc are available (seen on PPC64 Linux). - bpo-7855: Add tests for ctypes/winreg for issues found in IronPython. Initial patch by Dino Viehland. - bpo-11078: test___all__ now checks for duplicates in __all__. Initial patch by R. David Murray. - bpo-17712: Fix test_gdb failures on Ubuntu 13.04. - bpo-17835: Fix test_io when the default OS pipe buffer size is larger than one million bytes. - bpo-17065: Use process-unique key for winreg tests to avoid failures if test is run multiple times in parallel (eg: on a buildbot host). - bpo-12820: add tests for the xml.dom.minicompat module. Patch by John Chandler and Phil Connell. - bpo-17691: test_univnewlines now works with unittest test discovery. Patch by Zachary Ware. - bpo-17790: test_set now works with unittest test discovery. Patch by Zachary Ware. - bpo-17789: test_random now works with unittest test discovery. Patch by Zachary Ware. - bpo-17779: test_osx_env now works with unittest test discovery. Patch by Zachary Ware. - bpo-17766: test_iterlen now works with unittest test discovery. Patch by Zachary Ware. - bpo-17690: test_time now works with unittest test discovery. Patch by Zachary Ware. - bpo-17692: test_sqlite now works with unittest test discovery. Patch by Zachary Ware. - bpo-11995: test_pydoc doesn't import all sys.path modules anymore. - bpo-17448: test_sax now skips if there are no xml parsers available instead of raising an ImportError. - bpo-11420: make test suite pass with -B/DONTWRITEBYTECODE set. Initial patch by Thomas Wouters. - bpo-10652: make tcl/tk tests run after __all__ test, patch by Zachary Ware. - bpo-11963: remove human verification from test_parser and test_subprocess. - bpo-11732: add a new suppress_crash_popup() context manager to that disables crash popups on Windows and use it in test_faulthandler and test_capi. - bpo-13898: test_ssl no longer prints a spurious stack trace on Ubuntu. - bpo-17283: Share code between `` and `` in `Lib/test`. - bpo-17249: convert a test in test_capi to use unittest and reap threads. - bpo-17107: Test client-side SNI support in urllib.request thanks to the new server-side SNI support in the ssl module. Initial patch by Daniel Black. - bpo-17041: Fix testing when Python is configured with the --without-doc- strings. - bpo-16923: Fix ResourceWarnings in test_ssl. - bpo-15539: Added regression tests for Tools/scripts/ - bpo-17479: test_io now works with unittest test discovery. Patch by Zachary Ware. - bpo-17066: test_robotparser now works with unittest test discovery. Patch by Zachary Ware. - bpo-17334: test_index now works with unittest test discovery. Patch by Zachary Ware. - bpo-17333: test_imaplib now works with unittest test discovery. Patch by Zachary Ware. - bpo-17082: test_dbm* now work with unittest test discovery. Patch by Zachary Ware. - bpo-17079: test_ctypes now works with unittest test discovery. Patch by Zachary Ware. - bpo-17304: test_hash now works with unittest test discovery. Patch by Zachary Ware. - bpo-17303: test_future* now work with unittest test discovery. Patch by Zachary Ware. - bpo-17163: test_file now works with unittest test discovery. Patch by Zachary Ware. - bpo-16925: test_configparser now works with unittest test discovery. Patch by Zachary Ware. - bpo-16918: test_codecs now works with unittest test discovery. Patch by Zachary Ware. - bpo-16919: test_crypt now works with unittest test discovery. Patch by Zachary Ware. - bpo-16910: test_bytes, test_unicode, and test_userstring now work with unittest test discovery. Patch by Zachary Ware. - bpo-16905: test_warnings now works with unittest test discovery. Initial patch by Berker Peksag. - bpo-16898: test_bufio now works with unittest test discovery. Patch by Zachary Ware. - bpo-16888: test_array now works with unittest test discovery. Patch by Zachary Ware. - bpo-16896: test_asyncore now works with unittest test discovery. Patch by Zachary Ware. - bpo-16897: test_bisect now works with unittest test discovery. Initial patch by Zachary Ware. - bpo-16852: test_genericpath, test_posixpath, test_ntpath, and test_macpath now work with unittest test discovery. Patch by Zachary Ware. - bpo-16748: test_heapq now works with unittest test discovery. - bpo-10646: Tests rearranged for os.samefile/samestat to check for not just symlinks but also hard links. - bpo-15302: Switch regrtest from using getopt to using argparse. - bpo-15324: Fix regrtest parsing of --fromfile, --match, and --randomize options. - bpo-16702: test_urllib2_localnet tests now correctly ignores proxies for localhost tests. - bpo-16664: Add regression tests for glob's behaviour concerning entries starting with a ".". Patch by Sebastian Kreft. - bpo-13390: The ``-R`` option to regrtest now also checks for memory allocation leaks, using :func:`sys.getallocatedblocks()`. - bpo-16559: Add more tests for the json module, including some from the official test suite at Patch by Serhiy Storchaka. - bpo-16661: Fix the `os.getgrouplist()` test by not assuming that it gives the same output as :command:`id -G`. - bpo-16115: Add some tests for the executable argument to subprocess.Popen(). Initial patch by Kushal Das. - bpo-16126: PyErr_Format format mismatch in _testcapimodule.c. Patch by Serhiy Storchaka. - bpo-15304: Fix warning message when `os.chdir()` fails inside ``. Patch by Chris Jerdonek. - bpo-15802: Fix test logic in `TestMaildir.test_create_tmp()`. Patch by Serhiy Storchaka. - bpo-15557: Added a test suite for the webbrowser module, thanks to Anton Barkovsky. - bpo-16698: Skip posix test_getgroups when built with OS X deployment target prior to 10.6. Build ----- - bpo-16067: Add description into MSI file to replace installer's temporary name. - bpo-18257: Fix readlink usage in python-config. Install the python version again on Darwin. - bpo-18481: Add C coverage reporting with gcov and lcov. A new make target "coverage- report" creates an instrumented Python build, runs unit tests and creates a HTML. The report can be updated with "make coverage-lcov". - bpo-17845: Clarified the message printed when some module are not built. - bpo-18256: Compilation fix for recent AIX releases. Patch by David Edelsohn. - bpo-17547: In configure, explicitly pass -Wformat for the benefit for GCC 4.8. - bpo-15172: Document NASM 2.10+ as requirement for building OpenSSL 1.0.1 on Windows. - bpo-17591: Use lowercase filenames when including Windows header files. Patch by Roumen Petrov. - bpo-17550: Fix the --enable-profiling configure switch. - bpo-17425: Build with openssl 1.0.1d on Windows. - bpo-16754: Fix the incorrect shared library extension on linux. Introduce two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4. - bpo-5033: Fix building of the sqlite3 extension module when the SQLite library version has "beta" in it. Patch by Andreas Pelme. - bpo-17228: Fix building without pymalloc. - bpo-3718: Use AC_ARG_VAR to set MACHDEP in - bpo-16235: Implement python-config as a shell script. - bpo-16769: Remove outdated Visual Studio projects. - bpo-17031: Fix running regen in cross builds. - bpo-3754: fix typo in pthread AC_CACHE_VAL. - bpo-15484: Fix _PYTHON_PROJECT_BASE for srcdir != builddir builds; use _PYTHON_PROJECT_BASE in distutils/ - Drop support for Windows 2000 (changeset e52df05b496a). - bpo-17029: Let h2py search the multiarch system include directory. - bpo-16953: Fix socket module compilation on platforms with HAVE_BROKEN_POLL. Patch by Jeffrey Armstrong. - bpo-16320: Remove redundant Makefile dependencies for strings and bytes. - Cross compiling needs host and build settings. configure no longer creates a broken PYTHON_FOR_BUILD variable when --build is missing. - Fix cross compiling issue in, ensure that lib_dirs and inc_dirs are defined in cross compiling mode, too. - bpo-16836: Enable IPv6 support even if IPv6 is disabled on the build host. - bpo-16593: Have BSD 'make -s' do the right thing, thanks to Daniel Shahaf - bpo-16262: fix out-of-src-tree builds, if mercurial is not installed. - bpo-15298: ensure _sysconfigdata is generated in build directory, not source directory. - bpo-15833: Fix a regression in 3.3 that resulted in exceptions being raised if importlib failed to write byte-compiled files. This affected attempts to build Python out-of-tree from a read-only source directory. - bpo-15923: Fix a mistake in ```` that resulted in a TypeError after 2801bf875a24 (see #15801). - bpo-16135: Remove OS/2 support. - bpo-15819: Make sure we can build Python out-of-tree from a read-only source directory. (Somewhat related to issue #9860.) - bpo-15587: Enable Tk high-resolution text rendering on Macs with Retina displays. Applies to Tkinter apps, such as IDLE, on OS X framework builds linked with Cocoa Tk 8.5. - bpo-17161: make install now also installs a python3 man page. C API ----- - bpo-18351: Fix various issues in a function in importlib provided to help PyImport_ExecCodeModuleWithPathnames() (and thus by extension PyImport_ExecCodeModule() and PyImport_ExecCodeModuleEx()). - bpo-9369: The types of `char*` arguments of PyObject_CallFunction() and PyObject_CallMethod() now changed to `const char*`. Based on patches by Jörg Müller and Lars Buitinck. - bpo-17206: Py_CLEAR(), Py_DECREF(), Py_XINCREF() and Py_XDECREF() now expand their arguments once instead of multiple times. Patch written by Illia Polosukhin. - bpo-17522: Add the PyGILState_Check() API. - bpo-17327: Add PyDict_SetDefault. - bpo-16881: Fix Py_ARRAY_LENGTH macro for GCC < 3.1. - bpo-16505: Remove unused Py_TPFLAGS_INT_SUBCLASS. - bpo-16086: PyTypeObject.tp_flags and PyType_Spec.flags are now unsigned (unsigned long and unsigned int) to avoid an undefined behaviour with Py_TPFLAGS_TYPE_SUBCLASS ((1 << 31). PyType_GetFlags() result type is now unsigned too (unsigned long, instead of long). - bpo-16166: Add PY_LITTLE_ENDIAN and PY_BIG_ENDIAN macros and unified endianness detection and handling. Documentation ------------- - bpo-23006: Improve the documentation and indexing of dict.__missing__. Add an entry in the language datamodel special methods section. Revise and index its discussion in the stdtypes mapping/dict section. - bpo-17701: Improving strftime documentation. - bpo-18440: Clarify that `hash()` can truncate the value returned from an object's custom `__hash__()` method. - bpo-17844: Add links to encoders and decoders for bytes-to-bytes codecs. - bpo-14097: improve the "introduction" page of the tutorial. - bpo-17977: The documentation for the cadefault argument's default value in urllib.request.urlopen() is fixed to match the code. - bpo-6696: add documentation for the Profile objects, and improve profile/cProfile docs. Patch by Tom Pinckney. - bpo-15940: Specify effect of locale on time functions. - bpo-17538: Document XML vulnerabilties - bpo-16642: sched.scheduler timefunc initial default is time.monotonic. Patch by Ramchandra Apte - bpo-17047: remove doubled words in docs and docstrings reported by Serhiy Storchaka and Matthew Barnett. - bpo-15465: Document the versioning macros in the C API docs rather than the standard library docs. Patch by Kushal Das. - bpo-16406: Combine the pages for uploading and registering to PyPI. - bpo-16403: Document how distutils uses the maintainer field in PKG-INFO. Patch by Jyrki Pulliainen. - bpo-16695: Document how glob handles filenames starting with a dot. Initial patch by Jyrki Pulliainen. - bpo-8890: Stop advertising an insecure practice by replacing uses of the /tmp directory with better alternatives in the documentation. Patch by Geoff Wilson. - bpo-17203: add long option names to unittest discovery docs. - bpo-13094: add "Why do lambdas defined in a loop with different values all return the same result?" programming FAQ. - bpo-14901: Update portions of the Windows FAQ. Patch by Ashish Nitin Patil. - bpo-16267: Better document the 3.3+ approach to combining @abstractmethod with @staticmethod, @classmethod and @property - bpo-15209: Clarify exception chaining description in exceptions module documentation - bpo-15990: Improve argument/parameter documentation. - bpo-16209: Move the documentation for the str built-in function to a new str class entry in the "Text Sequence Type" section. - bpo-13538: Improve str() and object.__str__() documentation. - bpo-16489: Make it clearer that importlib.find_loader() needs parent packages to be explicitly imported. - bpo-16400: Update the description of which versions of a given package PyPI displays. - bpo-15677: Document that zlib and gzip accept a compression level of 0 to mean 'no compression'. Patch by Brian Brazil. - bpo-16197: Update winreg docstrings and documentation to match code. Patch by Zachary Ware. - bpo-8040: added a version switcher to the documentation. Patch by Yury Selivanov. - bpo-16241: Document -X faulthandler command line option. Patch by Marek Šuppa. - Additional comments and some style changes in the concurrent.futures URL retrieval example - bpo-16115: Improve subprocess.Popen() documentation around args, shell, and executable arguments. - bpo-13498: Clarify docs of os.makedirs()'s exist_ok argument. Done with great native- speaker help from R. David Murray. - bpo-15533: Clarify docs and add tests for `subprocess.Popen()`'s cwd argument. - bpo-15979: Improve timeit documentation. - bpo-16036: Improve documentation of built-in `int()`'s signature and arguments. - bpo-15935: Clarification of `argparse` docs, re: add_argument() type and default arguments. Patch contributed by Chris Jerdonek. - bpo-11964: Document a change in v3.2 to the behavior of the indent parameter of json encoding operations. - bpo-15116: Remove references to appscript as it is no longer being supported. Tools/Demos ----------- - bpo-18817: Fix a resource warning in Lib/ demo. Patch by Vajrasky Kok. - bpo-18439: Make patchcheck work on Windows for ACKS, NEWS. - bpo-18448: Fix a typo in Tools/demo/ - bpo-18457: Fixed saving of formulas and complex numbers in Tools/demo/ - bpo-18449: Make Tools/demo/ work again on Python 3. Patch by Févry Thibault. - bpo-12990: The "Python Launcher" on OSX could not launch python scripts that have paths that include wide characters. - bpo-15239: Make work again on Python 3. - bpo-17028: Allowed Python arguments to be supplied to the Windows launcher. - bpo-17156: now detects the encoding of source files and correctly writes and escapes non-ascii characters. - bpo-15539: Fix a number of bugs in Tools/scripts/ Now works with a "with" statement. no longer produces improper indentation. now works with continued lines broken after "class" or "def" keywords and with continuations at the start of line. - bpo-11797: Add a 2to3 fixer that maps reload() to imp.reload(). - bpo-10966: Remove the concept of unexpected skipped tests. - bpo-9893: Removed the Misc/Vim directory. - Removed the Misc/TextMate directory. - bpo-16245: Add the Tools/scripts/ script to parse the list of HTML5 entities and update the html.entities.html5 dictionary. - bpo-15378: Fix Tools/unicode/ Patch by Serhiy Storchaka. - bpo-16549: Make json.tool work again on Python 3 and add tests. Initial patch by Berker Peksag and Serhiy Storchaka. - bpo-13301: use ast.literal_eval() instead of eval() in Tools/i18n/ Patch by Serhiy Storchaka. Windows ------- - bpo-18569: The installer now adds .py to the PATHEXT variable when extensions are registered. Patch by Paul Moore. **(For information about older versions, consult the HISTORY file.)**