Contributing to this project


The issue tracker

We use GitHub issues for organizing bug reports and feature requests.

The following labels are of interest:

  • “Planning” is for issues that are still undecided, but where at least some discussion exists.
  • “Blocked” is for issues that can’t be worked on at the moment because some other unsolved problem exists. This problem may be a bug in some software dependency, for instance.
  • “Ready” contains issues that are ready to work on.

If you just want to get started with contributing, the “ready” issues are an option. Issues that are still in “Planning” are also an option, but require more upfront thinking and may turn out to be impossible to solve, or at least harder than anticipated. On the flip side those tend to be the more interesting issues as well, depending on how one looks at it.

All of those labels are also available as a kanban board on It is really just an alternative overview over all issues, but might be easier to comprehend.

Feel free to contact me or comment on the relevant issues for further information.

Reporting bugs

  • Make sure your problem isn’t already listed in Known Problems.
  • Make sure you have the absolutely latest version of vdirsyncer. For users of some Linux distributions such as Debian or Fedora this may not be the version that your distro offers. In those cases please file a bug against the distro package, not against upstream vdirsyncer.
  • Use --verbosity=DEBUG when including output from vdirsyncer.

Suggesting features

If you’re suggesting a feature, keep in mind that vdirsyncer tries not to be a full calendar or contacts client, but rather just the piece of software that synchronizes all the data. Take a look at the documentation for software working with vdirsyncer.

Submitting patches, pull requests

  • Discuss everything in the issue tracker first (or contact me somehow else) before implementing it.
  • Make sure the tests pass. See below for running them.
  • But not because you wrote too few tests.
  • Add yourself to AUTHORS.rst, and add a note to CHANGELOG.rst too.

Running tests, how to set up your development environment

For many patches, it might suffice to just let CI run the tests. However, CI is slow, so you might want to run them locally too. For this, set up a virtualenv and run this inside of it:

# Install development dependencies, including:
#  - vdirsyncer from the repo into the virtualenv
#  - stylecheckers (ruff) and code formatters (black)
make install-dev

# Install git commit hook for some extra linting and checking
pre-commit install

Then you can run:

pytest                # The normal testsuite
pre-commit run --all  # Run all linters (which also run via pre-commit)
make -C docs html     # Build the HTML docs, output is at docs/_build/html/
make -C docs linkcheck  # Check docs for any broken links

The Makefile has a lot of options that allow you to control which tests are run, and which servers are tested. Take a look at its code where they are all initialized and documented.

To tests against a specific DAV server, use DAV_SERVER:

make DAV_SERVER=xandikos test

The server will be initialised in a docker container and terminated at the end of the test suite.

If you have any questions, feel free to open issues about it.

Structure of the testsuite

Within tests/, there are three main folders:

  • system contains system- and also integration tests. A rough rule is: If the test is using temporary files, put it here.
  • unit, where each testcase tests a single class or function.
  • storage runs a generic storage testsuite against all storages.

The reason for this separation is: We are planning to generate separate coverage reports for each of those testsuites. Ideally unit would generate palatable coverage of the entire codebase on its own, and the combination of system and storage as well.