gtk/CONTRIBUTING.md

Contribution guidelines

Thank you for considering contributing to the GTK project!

These guidelines are meant for new contributors, regardless of their level of proficiency; following them allows the maintainers of the GTK project to more effectively evaluate your contribution, and provide prompt feedback to you. Additionally, by following these guidelines you clearly communicate that you respect the time and effort that the people developing GTK put into managing the project.

GTK is a complex free software GUI toolkit, and it would not exist without contributions from the free and open source software community. There are many things that we value:

• bug reporting and fixing
• documentation and examples
• tests
• new features

Please, do not use the issue tracker for support questions. If you have questions on how to use GTK effectively, you can use:

• the #gtk IRC channel on irc.gnome.org
• the gtk mailing list, for general questions on GTK
• the gtk-app-devel mailing list, for questions on application development with GTK
• the gtk-devel mailing list, for questions on developing GTK itself

You can also look at the GTK tag on Stack Overflow.

The issue tracker is meant to be used for actionable issues only.

How to report bugs

Security issues

You should not open a new issue for security related questions.

When in doubt, send an email to the security mailing list.

Bug reports

If you're reporting a bug make sure to list:

0. which version of GTK are you using?
1. which operating system are you using?
2. the necessary steps to reproduce the issue
3. the expected outcome
4. a description of the behavior; screenshots are also welcome
5. a small, self-contained example exhibiting the behavior; if this is not available, try reproducing the issue using the GTK examples or interactive tests

If the issue includes a crash, you should also include:

0. the eventual warnings printed on the terminal
1. a backtrace, obtained with tools such as GDB or LLDB

For small issues, such as:

• spelling/grammar fixes in the documentation
• typo correction
• comment clean ups
• changes to metadata files (CI, .gitignore)
• build system changes
• source tree clean ups and reorganizations

You should directly open a merge request instead of filing a new issue.

Features and enhancements

Feature discussion can be open ended and require high bandwidth channels; if you are proposing a new feature on the issue tracker, make sure to make an actionable proposal, and list:

0. what you're trying to achieve
1. prior art, in other toolkits or applications
2. design and theming changes

If you're proposing the integration of new features it helps to have multiple applications using shared or similar code, especially if they have iterated over it various times.

Each feature should also come fully documented, and with tests.

Your first contribution

Prerequisites

If you want to contribute to the GTK project, you will need to have the development tools appropriate for your operating system, including:

• Python 3.x
• Meson
• Ninja
• Gettext (19.7 or newer)
• a C99 compatible compiler

Up-to-date instructions about developing GNOME applications and libraries can be found on the GNOME Developer Center.

The GTK project uses GitLab for code hosting and for tracking issues. More information about using GitLab can be found on the GNOME wiki.

Dependencies

In order to get GTK from Git installed on your system, you need to have the required versions of all the software dependencies required by GTK; typically, this means a recent version of GLib, Cairo, Pango, and ATK, as well as the platform-specific dependencies for the windowing system you are using (Wayland, X11, Windows, or macOS).

The core dependencies for GTK are:

• GLib, GObject, and GIO
• Cairo
• Pango
• GdkPixbuf
• Epoxy
• ATK
• Graphene

GTK will attempt to download and build some of these dependencies if it cannot find them on your system.

Additionally, you may want to look at projects that create a development environment for you, like jhbuild and gvsbuild.

Getting started

You should start by forking the GTK repository from the GitLab web UI, and cloning from your fork:

$ git clone https://gitlab.gnome.org/yourusername/gtk.git
$ cd gtk

Note: if you plan to push changes to back to the main repository and have a GNOME account, you can skip the fork, and use the following instead:

$ git clone git@gitlab.gnome.org:GNOME/gtk.git
$ cd gtk

To compile the Git version of GTK on your system, you will need to configure your build using Meson:

$ meson _builddir .
$ cd _builddir
$ ninja

Typically, you should work on your own branch:

$ git checkout -b your-branch

Once you've finished working on the bug fix or feature, push the branch to the Git repository and open a new merge request, to let the GTK maintainers review your contribution.

Code reviews

Each contribution is reviewed by the core developers of the GTK project.

The CODE-OWNERS document contains the list of core contributors to GTK and the areas for which they are responsible; you should ensure to receive their review and signoff on your changes.

Commit messages

The expected format for git commit messages is as follows:

Short explanation of the commit

Longer explanation explaining exactly what's changed, whether any
external or private interfaces changed, what bugs were fixed (with bug
tracker reference if applicable) and so forth. Be concise but not too
brief.

Closes #1234

• Always add a brief description of the commit to the first line of the commit and terminate by two newlines (it will work without the second newline, but that is not nice for the interfaces).

• First line (the brief description) must only be one sentence and should start with a capital letter unless it starts with a lowercase symbol or identifier. Don't use a trailing period either. Don't exceed 72 characters.

• The main description (the body) is normal prose and should use normal punctuation and capital letters where appropriate. Consider the commit message as an email sent to the developers (or yourself, six months down the line) detailing why you changed something. There's no need to specify the how: the changes can be inlined.

• When committing code on behalf of others use the --author option, e.g. git commit -a --author "Joe Coder <joe@coder.org>" and --signoff.

• If your commit is addressing an issue, use the GitLab syntax to automatically close the issue when merging the commit with the upstream repository:

Closes #1234
Fixes #1234
Closes: https://gitlab.gnome.org/GNOME/gtk/issues/1234

• If you have a merge request with multiple commits and none of them completely fixes an issue, you should add a reference to the issue in the commit message, e.g. Bug: #1234, and use the automatic issue closing syntax in the description of the merge request.

Commit access to the GTK repository

GTK is part of the GNOME infrastructure. At the current time, any person with write access to the GNOME repository can merge changes to GTK. This is a good thing, in that it encourages many people to work on GTK, and progress can be made quickly. However, GTK is a fairly large and complicated project on which many other things depend, so to avoid unnecessary breakage, and to take advantage of the knowledge about GTK that has been built up over the years, we'd like to ask people committing to GTK to follow a few rules:

0. Ask first. If your changes are major, or could possibly break existing code, you should always ask. If your change is minor and you've been working on GTK for a while it probably isn't necessary to ask. But when in doubt, ask. Even if your change is correct, somebody may know a better way to do things. If you are making changes to GTK, you should be subscribed to the gtk-devel mailing list; this is a good place to ask about intended changes. The #gtk IRC channel on irc.gnome.org is also a good place to find GTK developers to discuss changes, but if you live outside of the EU/US time zones, an email to the gtk-devel mailing list is the most certain and preferred method.

1. Ask first.

2. Always write a meaningful commit message. Changes without a sufficient commit message will be reverted.

3. Never push to the master branch, or any stable branches, directly; you should always go through a merge request, to ensure that the code is tested on the CI infrastructure at the very least. A merge request is also the proper place to get a comprehensive code review from the core developers of GTK.

If you have been contributing to GTK for a while and you don't have commit access to the repository, you may ask to obtain it following the GNOME account process.