============
Contributing
============

Guidelines
==========

All the following guidelines must be met for contributions to be accepted. They
are all automatically enforced during the pull request process.


Python Support
--------------
Patchlab supports Python 3.6 or greater. This is automatically enforced by the
continuous integration (CI) suite.


Code Style
----------
We follow the `PEP8 <https://www.python.org/dev/peps/pep-0008/>`_ style guide
for Python. This is automatically enforced by the CI suite.

We are using `Black <https://github.com/ambv/black>` to automatically format
the source code. It is also checked in CI. The Black webpage contains
instructions to configure your editor to run it on the files you edit.


Tests
-----
The test suites can be run using `tox <http://tox.readthedocs.io/>`_ by simply
running ``tox`` from the repository root. All code must have test coverage or
be explicitly marked as not covered using the ``# no-qa`` comment. This should
only be done if there is a good reason to not write tests.

.. note:: The tests expect a PostgreSQL database to be available on localhost.
    This is automatically configured in the Vagrant environment and in the pull
    request CI environment.

Your pull request should contain tests for your new feature or bug fix. If
you're not certain how to write tests, we will be happy to help you.


Release notes
-------------
To add entries to the release notes, create a file in the ``news`` directory
with the ``source.type`` name format, where ``type`` is one of:

* ``feature``: for new features
* ``bug``: for bug fixes
* ``api``: for API changes
* ``dev``: for development-related changes
* ``author``: for contributor names
* ``other``: for other changes

And where the ``source`` part of the filename is:

* ``42`` when the change is described in issue ``42``
* ``PR42`` when the change has been implemented in pull request ``42``, and
  there is no associated issue
* ``Cabcdef`` when the change has been implemented in changeset ``abcdef``, and
  there is no associated issue or pull request.
* ``username`` for contributors (``author`` extention). It should be the
  username part of their commits' email address.

A preview of the release notes can be generated with ``towncrier --draft``.


Licensing
---------

Your commit messages must include a Signed-off-by tag with your name and e-mail
address, indicating that you agree to the `Developer Certificate of Origin
<https://developercertificate.org/>`_ version 1.1::

	Developer Certificate of Origin
	Version 1.1

	Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
	1 Letterman Drive
	Suite D4700
	San Francisco, CA, 94129

	Everyone is permitted to copy and distribute verbatim copies of this
	license document, but changing it is not allowed.


	Developer's Certificate of Origin 1.1

	By making a contribution to this project, I certify that:

	(a) The contribution was created in whole or in part by me and I
	    have the right to submit it under the open source license
	    indicated in the file; or

	(b) The contribution is based upon previous work that, to the best
	    of my knowledge, is covered under an appropriate open source
	    license and I have the right under that license to submit that
	    work with modifications, whether created in whole or in part
	    by me, under the same open source license (unless I am
	    permitted to submit under a different license), as indicated
	    in the file; or

	(c) The contribution was provided directly to me by some other
	    person who certified (a), (b) or (c) and I have not modified
	    it.

	(d) I understand and agree that this project and the contribution
	    are public and that a record of the contribution (including all
	    personal information I submit with it, including my sign-off) is
	    maintained indefinitely and may be redistributed consistent with
	    this project or the open source license(s) involved.

Use ``git commit -s`` to add the Signed-off-by tag.