File: contributing.rdoc [Ruby 2.3.4]

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    Contributing to Ruby

    Ruby has a vast and friendly community with hundreds of people contributing to a thriving open-source ecosystem. This guide is designed to cover ways for participating in the development of CRuby.

    There are plenty of ways for you to help even if you’re not ready to write code or documentation. You can help by reporting issues, testing patches, and trying out beta releases with your applications.

    How To Report

    If you’ve encountered a bug in Ruby please report it to the redmine issue tracker available at Do not report security vulnerabilities here, there is a separate channel for them.

    There are a few simple steps you should follow in order to receive feedback on your ticket.

    • If you haven’t already, sign up for an account on the bug tracker.

    • Try the latest version.

      If you aren’t already using the latest version, try installing a newer stable release. See Downloading Ruby.

    • Look to see if anyone already reported your issue, try searching on redmine for your problem.

    • If you can’t find a ticket addressing your issue, create a new one.

    • Choose the target version, usually current. Bugs will be first fixed in the current release and then backported.

    • Fill in the Ruby version you’re using when experiencing this issue (ruby -v).

    • Attach any logs or reproducible programs to provide additional information. Reproducible scripts should be as small as possible.

    • Briefly describe your problem. A 2-3 sentence description will help give a quick response.

    • Pick a category, such as core for common problems, or lib for a standard library.

    • Check the Maintainers list and assign the ticket if there is an active maintainer for the library or feature.

    • If the ticket doesn’t have any replies after 10 days, you can send a reminder.

    • Please reply to feedback requests. If a bug report doesn’t get any feedback, it’ll eventually get rejected.

    Reporting to downstream distributions

    You can report downstream issues for the following distributions via their bug tracker:

    Platform Maintainers

    For platform specific bugs in Ruby, you can assign your ticket to the current maintainer for a specific platform.

    The current active platform maintainers are as follows:

    mswin32, mswin64 (Microsoft Windows)

    NAKAMURA Usaku (usa)

    mingw32 (Minimalist GNU for Windows)

    Nobuyoshi Nakada (nobu)

    IA-64 (Debian GNU/Linux)

    TAKANO Mitsuhiro (takano32)

    Symbian OS

    Alexander Zavorine (azov)


    Yutaka Kanemoto (kanemoto)


    Akinori MUSHA (knu)


    Naohisa Goto (ngoto)

    RHEL, CentOS

    KOSAKI Motohiro kosaki

    Mac OS X

    Kenta Murata (mrkn)

    cygwin, bcc32, djgpp, wince, …

    none. (Maintainer WANTED)

    Reporting Security Issues

    Security vulnerabilities receive special treatment since they may negatively affect many users. There is a private mailing list that all security issues should be reported to and will be handled discretely. Email the list and the problem will be published after fixes have been released. You can also encrypt the issue using the PGP public key for the list.

    Reporting Other Issues

    If you’re having an issue with the website, or maybe the mailing list, you can contact the webmaster to help resolve the problem.

    The current webmaster is:

    • Hiroshi SHIBATA (hsbt)

    You can also report issues with the website on the issue tracker:

    Resolve Existing Issues

    As a next step beyond reporting issues you can help the core team resolve existing issues. If you check the Everyone’s Issues list in GitHub Issues, you will find a lot of issues already requiring attention. What can you do for these? Quite a bit, actually:

    When a bug report goes for a while without any feedback, it goes to the bug graveyard which is unfortunate. If you check the issues list you will find lots of delinquent bugs that require attention.

    You can help by verifying the existing tickets, try to reproduce the reported issue on your own and comment if you still experience the bug. Some issues lack attention because of too much ambiguity, to help you can narrow down the problem and provide more specific details or instructions to reproduce the bug. You might also try contributing a failing test in the form of a patch, which we will cover later in this guide.

    It may also help to try out patches other contributors have submitted to redmine, if gone without notice. In this case the patch command is your friend, see man patch for more information. Basically this would go something like this:

    cd path/to/ruby/trunk
    patch -p0 < path/to/patch

    You will then be prompted to apply the patch with the associated files. After building ruby again, you should try to run the tests and verify if the change actually worked or fixed the bug. It’s important to provide valuable feedback on the patch that can help reach the overall goal, try to answer some of these questions:

    • What do you like about this change?

    • What would you do differently?

    • Are there any other edge cases not tested?

    • Is there any documentation that would be affected by this change?

    If you can answer some or all of these questions, you’re on the right track. If your comment simply says “+1”, then odds are that other reviewers aren’t going to take it too seriously. Show that you took the time to review the patch.

    How To Request Features

    If there’s a new feature that you want to see added to Ruby, you will need to write a convincing proposal and patch to implement the feature.

    For new features in CRuby, use the ‘Feature’ tracker on ruby-trunk. For non-CRuby dependent features, features that would apply to alternate Ruby implementations such as JRuby and Rubinius, use the CommonRuby tracker.

    When writing a proposal be sure to check for previous discussions on the topic and have a solid use case. You will need to be persuasive and convince Matz on your new feature. You should also consider the potential compatibility issues that this new feature might raise.

    Consider making your feature into a gem, and if there are enough people who benefit from your feature it could help persuade ruby-core. Although feature requests can seem like an alluring way to contribute to Ruby, often these discussions can lead nowhere and exhaust time and energy that could be better spent fixing bugs. Choose your battles.

    A good template for a feature proposal should look something like this:


    Summary of your feature


    Describe current behavior and why it is problem. Related work, such as solutions in other language helps us to understand the problem.


    Describe your proposal in details


    If it has complicated feature, describe it


    How would your feature be used? Who will benefit from it?


    Discuss about this proposal. A list of pros and cons will help start discussion.


    Limitation of your proposal

    Another alternative proposal

    If there are alternative proposals, show them.

    See also

    Links to the other related resources


    At the Ruby Developer Meeting in Japan, committers discuss Feature Proposals together in Tokyo. We will judge proposals and then accept, reject, or give feedback for them. If you have a stalled proposal, making a slide to submit is good way to get feedback.

    Slides should be:

    • One-page slide

    • Include a corresponding ticket number

    • MUST include a figure and/or short example code

    • SHOULD have less sentence in natural language (try to write less than 140 characters)

    • It is RECOMMENDED to itemize: motivation/use case, proposal, pros/cons, corner case

    • PDF or Image (Web browsers can show it)

    Please note:

    • Even if the proposal is generally acceptable, it won’t be accepted without writing corner cases in the ticket

    • Slide’s example: DevelopersMeeting20130727Japan

    Backport Requests

    When a new version of Ruby is released, it starts at patch level 0 (p0), and bugs will be fixed first on the trunk branch. If it’s determined that a bug exists in a previous version of Ruby that is still in the bug fix stage of maintenance, then a patch will be backported. After the maintenance stage of a particular Ruby version ends, it goes into “security fix only” mode which means only security related vulnerabilities will be backported. Versions in End-of-life (EOL) will not receive any updates and it is recommended you upgrade as soon as possible.

    If a major security issue is found or after a certain amount of time since the last patch level release, a new patch-level release will be made.

    When submitting a backport request please confirm the bug has been fixed in newer versions and exists in maintenance mode versions. There is a backport tracker for each major version still in maintenance where you can request a particular revision merged in the affected version of Ruby.

    Each major version of Ruby has a release manager that should be assigned to handle backport requests. You can find the list of release managers on the wiki.

    Branch Maintainers

    A branch maintainer maintains a branch and releases a new release of Ruby. The branch depends on the associated version of Ruby, such as ruby_1_8_7 for version 1.8.7. The current branch maintainers are as follows:




    Chikanaga Tomoyuki (nagachika)


    NAKAMURA Usaku (usa)


    NAKAMURA Usaku (usa)

    ruby_1_9_3, ruby_1_9_2, ruby_1_9_1






    ruby_1_8_6 …


    Running tests

    In order to help resolve existing issues and contributing patches to Ruby you need to be able to run the test suite.

    CRuby uses subversion for source control, you can find installation instructions and lots of great info to learn subversion on the For other resources see the ruby-core documentation on

    This guide will use git for contributing. The git homepage has installation instructions with links to documentation for learning more about git. There is a mirror of the subversion repository on github.

    Install the prerequisite dependencies for building the CRuby interpreter to run tests.

    • C compiler

    • autoconf

    • bison

    • gperf

    • ruby - Ruby itself is prerequisite in order to build Ruby from source. It can be 1.8.

    You should also have access to development headers for the following libraries, but these are not required:

    • Tcl/Tk


    • GDBM

    • OpenSSL

    • readline/editline(libedit)

    • zlib

    • libffi

    • libyaml

    • libexecinfo (FreeBSD)

    Now let’s build CRuby:

    • Checkout the CRuby source code:

      git clone git:// ruby-trunk
    • Generate the configuration files and build:

      cd ruby-trunk
      mkdir build && cd build # its good practice to build outside of source dir
      mkdir ~/.rubies # we will install to .rubies/ruby-trunk in our home dir
      ../configure --prefix="${HOME}/.rubies/ruby-trunk"
      make && make install

    After adding Ruby to your PATH, you should be ready to run the test suite:

    make test

    You can also use test-all to run all of the tests with the RUNRUBY interpreter just built. Use TESTS or RUNRUBYOPT to pass parameters, such as:

    make test-all TESTS=-v

    This is also how you can run a specific test from our build dir:

    make test-all TESTS=drb/test_drb.rb

    For older versions of Ruby you will need to run the build setup again after checking out the associated branch in git, for example if you wanted to checkout 1.9.3:

    git clone git:// --branch ruby_1_9_3

    Contributing Documentation

    If you’re interested in contributing documentation directly to CRuby there is a wealth of information available at

    There is also the Ruby Reference Manual in Japanese.

    Contributing A Patch

    Deciding what to patch

    Before you submit a patch, there are a few things you should know:

    • Pay attention to the maintenance policy for stable and maintained versions of Ruby.

    • Released versions in security mode will not merge feature changes.

    • Search for previous discussions on ruby-core to verify the maintenance policy

    • Patches must be distributed under Ruby’s license.

    • This license may change in the future, you must join the discussion if you don’t agree to the change

    To improve the chance your patch will be accepted please follow these simple rules:

    • Bug fixes should be committed on trunk first

    • Format of the patch file must be a unified diff (ie: diff -pu, svn diff, or git diff)

    • Don’t introduce cosmetic changes

    • Follow the original coding style of the code

    • Don’t mix different changes in one commit

    First thing you should do is check out the code if you haven’t already:

    git clone git:// ruby-trunk

    Now create a dedicated branch:

    cd ruby-trunk
    git checkout -b my_new_branch

    The name of your branch doesn’t really matter because it will only exist on your local computer and won’t be part of the official Ruby repository. It will be used to create patches based on the differences between your branch and trunk, or edge Ruby.

    Coding style

    Here are some general rules to follow when writing Ruby and C code for CRuby:

    • Indent 4 spaces for C with tabs for eight-space indentation (emacs default)

    • Indent 2 space tabs for Ruby

    • Do not use TABs in ruby codes

    • ANSI C style for 1.9+ for function declarations

    • Follow C90 (not C99) Standard

    • PascalStyle for class/module names.

    • UNDERSCORE_SEPARATED_UPPER_CASE for other constants.

    • Capitalize words.

    • ABBRs should be all upper case.

    • Do as others do


    Although not required, if you wish to add a ChangeLog entry for your change please note:

    You can use the following template for the ChangeLog entry on your commit:

    Thu Jan  1 00:00:00 2004  Your Name  <>
          * filename (function): short description of this commit.
            This should include your intention of this change.
            [bug:#number] [mailinglist:number]
          * filename2 (function2): additional description for this file/function.

    This follows GNU Coding Standards for Change Logs, some other requirements and tips:

    • Timestamps must be in JST (+09:00) in the style as above.

    • Two spaces between the timestamp and your name. Two spaces between your name and your mail address.

    • One blank line between the timestamp and the description.

    • Indent the description with TAB. 2nd line should begin with TAB+2SP.

    • Write a entry (*) for each change.

    • Refer to redmine issue or discussion on the mailing list.

    • For GitHub issues, use [GH-#] (such as [Fixes GH-234]

    • One blank line between entries.

    • Do as other committers do.

    You can generate the ChangeLog entry by running make change

    When you’re ready to commit, copy your ChangeLog entry into the commit message, keeping the same formatting and select your files:

    git commit ChangeLog path/to/files

    In the likely event that your branch becomes outdated, you will have to update your working branch:

    git fetch origin
    git rebase remotes/origin/master

    Now that you’ve got some code you want to contribute, let’s get set up to generate a patch. Start by forking the github mirror, check the github docs on forking if you get stuck here. You will only need a github account if you intend to host your repository on github.

    Next copy the writable url for your fork and add it as a git remote, replace “my_username” with your github account name:

    git remote add my_fork
    # Now we can push our branch to our fork
    git push my_fork my_new_branch

    In order to generate a patch that you can upload to the bug tracker, we can use the github interface to review our changes just visit…my_new_branch

    Next, you can simply add ‘.patch’ to the end of this URL and it will generate the patch for you, save the file to your computer and upload it to the bug tracker. Alternatively you can submit a pull request, but for the best chances to receive feedback add it is recommended you add it to redmine.

    Since git is a distributed system, you are welcome to host your git repository on any publicly accessible hosting site, including hosting your own You may use the ‘git format-patch’ command to generate patch files to upload to redmine. You may also use the ‘git request-pull’ command for formatting pull request messages to redmine.