Contributions to python-debian are most welcome. Where possible, please discuss your thoughts with the maintainers via the mailing list as soon as you can so that we can help ensure that the process of including new code is as painless as possible.

python3-debian gets installed by the Debian Installer as part of the "standard" task (reportbug depends on python3-reportbug depends on python3-debian). It is also pulled in to many desktop installations through tools such as gdebi. Given how widely deployed these packages are:

• Be very conservative in adding new dependencies. If a package is not already a dependency is not already within the set of packages installed by the standard task, the additional dependency should be discussed on the maintainer list.
• Be very careful with code changes since you could reasonably break a lot of boxes with a botched upload. There is a test suite (see below).
• There are lots of users of the python-debian API beyond the packages within Debian, including parts of Debian's infrastructure and scripts developed by users. There is no real way of finding those users and notifying them of API changes. Backwards compatibility is very important.

In general, code in python-debian should be reasonably generous in what it accepts and quite strictly correct in its output.

Ideally, python-debian should be written to match what is defined in Debian Policy. Code for features that are not yet documented in Policy should be clearly marked as experimental; it is not unusual for the Policy process to result in changes to the draft specification that then requires API changes.

Given Policy's role in documenting standard practice and not in developing new specifications, some behaviour is not specified by Policy but is instead encoded within other parts of the ecosystem such as dpkg, apt or dak. In such situations, python-debian should remain consistent with other implementations.

Notable specifications:

• Debian Policy

• dpkg-dev man pages including:

  • deb-control(5), the control file in the binary package (generated from debian/control in the source package)
  • deb-version(5), Debian version strings.
  • deb-changelog(5), changelogs for Debian packages.
  • deb-changes(5), changes files that developers upload to add new packages to the archive.
  • dsc(5), Debian Source Control file that defines the files that are part of a source package.

• Debian mirror format, including documentation for Packages, Sources files etc.
• dak documentation, the Debian Archive Kit that manages the contents of the Debian archive.

• Code should be whitespace clean, pep8 & pylint compatible; a .pylintrc configuration file is provided is also run on salsa.debian.org as part of the CI checks for merge requests. (Where pep8 and pylintrc disagree about whitespace, follow pylint's recommendations.)
• Write type annotations to help mypy --strict understand the types and ensure that mypy is happy with the code.
• Write tests. For everything.
• Write docstrings in rst format so that sphinx can generate API documentation.

The pylint and mypy tools can be run easily from debian/rules to track code quality:

$ ./debian/rules qa

Please make sure all tests in the test suite pass after any change is made.

Adding a test that exposes a given bug and then fixing the bug (and hence the test suite) is the preferred method for bug fixing. Please reference the bug number and describe the problem and solution in the comments for the bug so that those who come after you can understand both 'what' and 'why'.

The tests use absolute imports and do not alter sys.path so that they can be used to test either the installed package or the current working tree. Tests can be run either from the top-level directory or from the lib/ directory:

Run all tests from the top most directory of the source package:

$ py.test -v -rsx --doctest-modules lib/

Or just run some selected tests:

$ py.test -v -rsx --doctest-modules lib/debian/tests/test_deb822.py::TestDeb822::test_buildinfo

$ py.test -v -rsx --doctest-modules debian/tests/test_deb822.py

For simplicity all the tests can also be run as:

$ ./debian/rules test

The tests are run as part of the package build and also as a CI job on salsa.debian.org. Tests will be run against merge requests automatically. Running the tests with different encodings specified in the environment (using LC_ALL) is a good way of catching errors in handling the encoding of files.

Bug tracking for python-debian is undertaken in the Debian bug tracking system (BTS). The BTS has been configured to display bugs split by module (see usercategories configuration below). Bug reporters and developers may find the view with only the per-module categorisation (and no severity or status organisation) useful.

Bug reporters are welcome to add the relevant usertags to their bug reports but don't worry if you do not; they can be easily added in later by people who are more familiar with the BTS. Adding the User and Usertag pseudo-headers to the bug report would mark the bug as being in the deb822 module, for instance:

To: submit@bugs.debian.org
Subject: title-of-bug

Package: python-debian
[ ... ]
User: python-debian@packages.debian.org
Usertags: deb822

description-of-bug ...

For reference, the BTS usercategories configuration (which lists the known usertags for the BTS view) is as follows:

The usertags are derived from the Python names of he (sub)modules. Note that usertags cannot include underscores and thus the the Python module name debian_support becomes the BTS usertag debian-support.

Documentation on usercategories and usertags:

• Wiki guide on usertags
• BTS documentation

When uploading the package, it should be uploaded both to Debian and also to PyPI. Please upload the source tarball (sdist) and also an egg (bdist_egg) and a wheel (bdist_wheel), all built for Python 3. The python3-wheel package needs to be installed to build the wheel.

The following developers have access to the PyPI project to be able to upload it.

• pkern
• stuart

The upload procedure is:

$ ./debian/rules dist
$ twine upload --sign dist/python?debian-x.y.z.*

Test uploads to TestPyPI can be made and tested with:

$ twine upload --sign --repository testpypi dist/python-debian-x.y.z.tar.gz
$ virtualenv python-debian-test
$ cd python-debian-test
$ . bin/activate
$ pip install --index-url https://test.pypi.org/simple/ \
          --extra-index-url https://pypi.org/simple python-debian