How to contribute

So you want to contribute to the Powerline project? Awesome! This document describes the guidelines you should follow when making contributions to the project.

Please note that these guidelines aren't mandatory in any way, but your pull request will be merged a lot faster if you follow them.

Getting started

• Make sure you have a GitHub account.
• Submit an issue on GitHub, assuming one does not already exist.
  • Clearly describe the issue.
  • If the issue is a bug: make sure you include steps to reproduce, and include the earliest revision that you know has the issue.
• Fork the repository on GitHub.

Making changes

• Create a topic branch from where you want to base your work.
  • Powerline uses the Git Flow branching model.
  • Most contributions should be based off the develop branch.
  • Prefix your branch with feature/ if you're working on a new feature.
  • Include the issue number in your topic branch, e.g. 321-fix-some-error or feature/123-a-cool-feature.
• Make commits of logical units.
• Run your code through flake8 and fix any programming style errors. Use common sense regarding whitespace warnings, not all warnings need to be fixed.
• Make sure your commit messages are in the proper format. The summary must be no longer than 70 characters. Refer to any related issues with e.g. Ref #123 or Fixes #234 at the bottom of the commit message. Commit messages can use Markdown with the following exceptions:
  • No HTML extensions.
  • Only indented code blocks (no ``` blocks).
  • Long links should be moved to the bottom if they make the text wrap or extend past 72 columns.
• Make sure you have added the necessary tests for your changes.
• Run all the tests to assure nothing else was accidentally broken.

Programming style

• The project uses tabs for indentation and spaces for alignment, this is also included in a vim modeline on top of every script file.

• Run your code through flake8 --ignore=W191,E501,E128,W291,E126,E101 to fix any style errors. Use common sense regarding whitespace warnings, not all flake8 warnings need to be fixed.

• Trailing whitespace to indicate a continuing paragraph is OK in comments, documentation and commit messages.

• It is allowed to have too long lines. It is advised though to avoid lines wider then a hundred of characters.

• Imports have the following structure:

  1. Shebang and modeline in a form

     #!/usr/bin/env python
     # vim:fileencoding=utf-8:noet
     

     . Modeline is required, shebang is not. If shebang is present file must end with

     if __name__ == '__main__':
         # Actual script here
     

  2. Module docstring.

  3. __future__ import exactly in a form

     from __future__ import (unicode_literals, division, absolute_import, print_function)
     

     (powerline.shell is the only exception due to problems with argparse). It is not separated by newline with shebang and modeline, but is with docstring.

  4. Standard python library imports in a form import X.

  5. Standard python library imports in a form from X import Y.

  6. Third-party (non-python and non-powerline) library imports in a form import X.

  7. Third-party library imports in a form from X import Y.

  8. Powerline non-test imports in a form from powerline.X import Y.

  9. Powerline test imports in a form import tests.vim as vim_module.

  10. Powerline test imports in a form from tests.X import Y.

  Each entry is separated by newline from another entry. Any entry except for the first and third ones is optional. Example with all entries:

  #!/usr/bin/env python
  # vim:fileencoding=utf-8:noet
  
  '''Powerline super module'''
  
  from __future__ import (unicode_literals, division, absolute_import, print_function)
  
  import sys
  
  from argparse import ArgumentParser
  
  import psutil
  
  from colormath.color_diff import delta_e_cie2000
  
  from powerline.lib.unicode import u
  
  import tests.vim as vim_module
  
  from tests import TestCase
  

Submitting changes

• Push your changes to a topic branch in your fork of the repository.
• If necessary, use git rebase -i <revision> to squash or reword commits before submitting a pull request.
• Submit a pull request to powerline repository.