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Contributing

There are many ways in which you can contribute to Kivy. Code patches are just one thing amongst others that you can submit to help the project. We also welcome feedback, bug reports, feature requests, documentation improvements, advertisement & advocating, testing, graphics contributions and many other ideas. Just talk to us if you want to help, and we will help you help us.

Feedback

This is by far the easiest way to contribute something. If you’re using Kivy for your own project, don’t hesitate sharing. It doesn’t have to be a high-class enterprise app, obviously. It’s just incredibly motivating to know that people use the things you develop and what it enables them to do. If you have something that you would like to tell us, please don’t hesitate. Screenshots and videos are also very welcome! We’re also interested in the problems you had when getting started. Please feel encouraged to report any obstacles you encountered such as missing documentation, misleading directions or similar. We are perfectionists, so even if it’s just a typo, let us know.

Reporting an Issue

If you found anything wrong, a crash, segfault, missing documentation, invalid spelling or just weird examples, please take 2 minutes to report the issue.

  1. Move your logging level to debug by editing <user_directory>/.kivy/config.ini:

    [kivy]
    log_level = debug
    
  2. Execute your code again, and copy/paste the complete output to http://gist.github.com/, including the log from Kivy and the python backtrace.

  3. Open https://github.com/kivy/kivy/issues/

  4. Set the title of your issue

  5. Explain exactly what to do to reproduce the issue and paste the link of the output posted on http://gist.github.com/

  6. Validate the issue and you’re done!

If you are feeling up to it, you can also try to resolve the bug, and contribute by sending us the patch :) Read the next section to find out how to do this.

Code Contributions

Code contributions (patches, new features) are the most obvious way to help with the project’s development. Since this is so common we ask you to follow our workflow to most efficiently work with us. Adhering to our workflow ensures that your contribution won’t be forgotten or lost. Also, your name will always be associated with the change you made, which basically means eternal fame in our code history (you can opt-out if you don’t want that).

Coding style

  • If you haven’t done it yet, read the PEP8 about coding style in python.

  • Activate the pep8 check on git commits like this:

    make hook

This will pass the code added to the git staging zone (about to be committed) through a pep8 checker program when you do a commit, and ensure that you didn’t introduce pep8 errors. If you did, the commit will be rejected: please correct the errors and try again.

Performance

  • take care of performance issues: read Python performance tips
  • cpu intensive parts of Kivy are written in cython: if you are doing a lot of computation, consider using it too.

Git & GitHub

We use git as our version control system for our code base. If you have never used git or a similar DVCS (or even any VCS) before, we strongly suggest you take a look at the great documentation that is available for git online. The Git Community Book or the Git Screencasts are both great ways to learn git. Trust us when we say that git is a great tool. It may seem daunting at first, but after a while you’ll (hopefully) love it as much as we do. Teaching you git, however, is well beyond the scope of this document.

Also, we use GitHub to host our code. In the following we will assume that you have a (free) GitHub account. While this part is optional, it allows for a tight integration between your patches and our upstream code base. If you don’t want to use GitHub, we assume you know what you are doing anyway.

Code Workflow

So here is the initial setup to begin with our workflow (you only need to do this once to install Kivy). Basically you follow the installation instructions from Installing Kivy for Development, but you don’t clone our repository, you fork it. Here are the steps:

  1. Log in to GitHub

  2. Create a fork of the Kivy repository by clicking the fork button.

  3. Clone your fork of our repository to your computer. Your fork will have the git remote name ‘origin’ and you will be on branch ‘master’:

    git clone https://github.com/username/kivy.git
  4. Compile and set up PYTHONPATH or install (see Installing Kivy for Development).

  5. Install our pre-commit hook that ensures your code doesn’t violate our styleguide by executing make hook from the root directory of your clone. This will run our styleguide check whenever you do a commit, and if there are violations in the parts that you changed, your commit will be aborted. Fix & retry.

  6. Add the kivy repo as a remote source:

    git remote add kivy https://github.com/kivy/kivy.git

Now, whenever you want to create a patch, you follow the following steps:

  1. See if there is a ticket in our bug tracker for the fix or feature and announce that you’ll be working on it if it doesn’t yet have an assignee.

  2. Create a new, appropriately named branch in your local repository for that specific feature or bugfix. (Keeping a new branch per feature makes sure we can easily pull in your changes without pulling any other stuff that is not supposed to be pulled.):

    git checkout -b new_feature
  3. Modify the code to do what you want (e.g., fix it).

  4. Test the code. Try to do this even for small fixes. You never know whether you have introduced some weird bug without testing.

  5. Do one or more minimal, atomic commits per fix or per feature. Minimal/Atomic means keep the commit clean. Don’t commit other stuff that doesn’t logically belong to this fix or feature. This is not about creating one commit per line changed. Use git add -p if necessary.

  6. Give each commit an appropriate commit message, so that others who are not familiar with the matter get a good idea of what you changed.

  7. Once you are satisfied with your changes, pull our upstream repository and merge it with you local repository. We can pull your stuff, but since you know exactly what’s changed, you should do the merge:

    git pull kivy master
  8. Push your local branch into your remote repository on GitHub:

    git push origin new_feature
  9. Send a Pull Request with a description of what you changed via the button in the GitHub interface of your repository. (This is why we forked initially. Your repository is linked against ours.)

Warning

If you change parts of the code base that require compilation, you will have to recompile in order for your changes to take effect. The make command will do that for you (see the Makefile if you want to know what it does). If you need to clean your current directory from compiled files, execute make clean. If you want to get rid of all files that are not under version control, run make distclean (Caution: If your changes are not under version control, this command will delete them!)

Now we will receive your pull request. We will check whether your changes are clean and make sense (if you talked to us before doing all of this we will have told you whether it makes sense or not). If so, we will pull them and you will get instant karma. Congratulations, you’re a hero!

Documentation Contributions

Documentation contributions generally follow the same workflow as code contributions, but are just a bit more lax.

  1. Following the instructions above,

    1. Fork the repository.
    2. Clone your fork to your computer.
    3. Setup kivy repo as a remote source.
  2. Install python-sphinx. (See docs/README for assistance.)

  3. Use ReStructuredText_Markup to make changes to the HTML documentation in docs/sources.

To submit a documentation update, use the following steps:

  1. Create a new, appropriately named branch in your local repository:

    git checkout -b my_docs_update
  2. Modify the documentation with your correction or improvement.

  3. Re-generate the HTML pages, and review your update:

    make html
  4. Give each commit an appropriate commit message, so that others who are not familiar with the matter get a good idea of what you changed.

  5. Keep each commit focused on a single related theme. Don’t commit other stuff that doesn’t logically belong to this update.

  6. Push to your remote repository on GitHub:

    git push
  7. Send a Pull Request with a description of what you changed via the button in the GitHub interface of your repository.

We don’t ask you to go through all the hassle just to correct a single typo, but for more complex contributions, please follow the suggested workflow.

Docstrings

Every module/class/method/function needs a docstring, so use the following keywords when relevant:

  • .. versionadded:: to mark the version in which the feature was added.
  • .. versionchanged:: to mark the version in which the behaviour of the feature was changed.
  • .. note:: to add additional info about how to use the feature or related feature.
  • .. warning:: to indicate a potential issue the user might run into using the feature.

Examples:

def my_new_feature(self, arg):
    """
    New feature is awesome

    .. versionadded:: 1.1.4

    .. note:: This new feature will likely blow your mind

    .. warning:: Please take a seat before trying this feature
    """

Will result in:

def my_new_feature(self, arg):

“”” New feature is awesome

New in version 1.1.4.

Note

This new feature will likely blow your mind

Warning

Please take a seat before trying this feature

“”“

When refering to other parts of the api use:

  • :mod:`~kivy.module` to refer to a module
  • :class:`~kivy.module.Class` to refer to a class
  • :meth:`~kivy.module.Class.method` to refer to a method
  • :doc:`api-kivy.module` to refer to the documentation of a module (same for a class and a method)

Obviously replacing module Class and method with their real name, and using using ‘.’ to separate modules refering to imbricated modules, e.g:

:mod:`~kivy.uix.floatlayout`
:class:`~kivy.uix.floatlayout.FloatLayout`
:meth:`~kivy.core.window.WindowBase.toggle_fullscreen`
:doc:`/api-kivy.core.window`

Will result in:

:doc: and :mod: are essentially the same, except for an anchor in the url which makes :doc: prefered for the cleaner url.

To build your documentation, run:

make html

If you updated your kivy install, and have some trouble compiling docs, run:

make clean force html

The docs will be generated in docs/build/html. For more information on docstring formatting, please refer to the official Sphinx Documentation.

Unit tests contributions

For the testing team, we have the document Unit tests that explains how Kivy unit tests work and how you can create your own. Use the same approach as the Code Workflow to submit new tests.