Contributing

Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

You can contribute in many ways:

Types of Contributions

Implement Features, Indices or Indicators

xclim’s structure makes it easy to create and register new user-defined indices and indicators. Refer to the Customizing and controlling xclim page for more information.

Look through the GitHub issues for features. Anything tagged with “enhancement” and “help wanted” is open to whoever wants to implement it.

Warning

If you plan to implement new indicators into xclim, be aware that metadata translations for all official xclim languages (for now only French) must be provided, or else the tests will fail and the PR will not be mergeable. See Internationalization for more details. Don’t hesitate to ask for help in your PR for this task!

Report Bugs

Report bugs at https://github.com/Ouranosinc/xclim/issues.

If you are reporting a bug, please include:

• Your operating system name and version.

• Any details about your local setup that might be helpful in troubleshooting.

• Detailed steps to reproduce the bug.

Fix Bugs

Look through the GitHub issues for bugs. Anything tagged with “bug” and “help wanted” is open to whoever wants to implement it.

Write Documentation

xclim could always use more documentation, whether as part of the official xclim docs, in docstrings, or even on the web in blog posts, articles, and such.

Submit Feedback

The best way to send feedback is to file an issue at https://github.com/Ouranosinc/xclim/issues.

If you are proposing a feature:

• Explain in detail how it would work.

• Keep the scope as narrow as possible, to make it easier to implement.

• Remember that this is a volunteer-driven project, and that contributions are welcome :)

Get Started!

Ready to contribute? Here’s how to set up xclim for local development.

1. Fork the xclim repo on GitHub.

2. Clone your fork locally:

   $ git clone git@github.com:Ouranosinc/xclim.git
   $ cd xclim/
   

3. Create a development environment. Assuming you have virtualenvwrapper installed, this is how you set up your fork for local development:

   # For virtualenv environments (ensure that you have the necessary system libraries).
   $ mkvirtualenv xclim
   $ pip install -e .[dev]
   
   # For Anaconda/Miniconda environments:
   $ conda create -n xclim python=3.7 --file=environment.yml
   $ pip install -e .[dev]
   

4. Create a branch for local development:

   $ git checkout -b name-of-your-bugfix-or-feature
   

   Now you can make your changes locally!

5. When you’re done making changes, check that you verify your changes with black, pydocstyle, and run the tests, including testing other available Python versions with tox:

   $ black --check --target-version py37 xclim xclim/testing/tests
   $ black --check --target-version py37 --include "\.ipynb$" docs
   $ flake8 xclim xclim/testing/tests
   $ pytest --nbval docs/notebooks
   $ pytest --rootdir=xclim/testing/tests --xdoctest xclim
   $ pydocstyle --convention=numpy --match='(?!test_).*\.py' xclim
   $ tox
   

6. Before committing your changes, we ask that you install pre-commit in your development environment. Pre-commit runs git hooks that ensure that your code resembles that of the project and catches and corrects any small errors or inconsistencies when you git commit:

   # To install the necessary pre-commit hooks:
   $ pre-commit install
   # To run pre-commit hooks manually:
   $ pre-commit run --all-files
   

7. Commit your changes and push your branch to GitHub:

   $ git add *
   
   $ git commit -m "Your detailed description of your changes."
   # If installed, `pre-commit` will run checks at this point:
   # If no errors are found, changes will be committed.
   # If errors are found, modifications will be made and warnings will be raised if intervention is needed. After changes, simply `git commit` again.
   
   $ git push origin name-of-your-bugfix-or-feature
   

8. Submit a pull request through the GitHub website.

Pull Request Guidelines

Before you submit a pull request, please follow these guidelines:

1. Open an issue on our GitHub repository with your issue that you’d like to fix or feature that you’d like to implement.

2. Perform the changes, commit and push them either to new a branch within Ouranosinc/xclim or to your personal fork of xclim.

Warning

Try to keep your contributions within the scope of the issue that you are addressing. While it might be tempting to fix other aspects of the library as it comes up, it’s better to simply to flag the problems in case others are already working on it.

Consider adding a “# TODO:” comment if the need arises.

3. Pull requests should raise test coverage for the xclim library. Code coverage is an indicator of how extensively tested the library is. If you are adding a new set of functions, they must be tested and coverage percentage should not significantly decrease.

4. If the pull request adds functionality, your functions should include docstring explanations. So long as the docstrings are syntactically correct, sphinx-autodoc will be able to automatically parse the information. Please ensure that the docstrings and documentation adhere to the following standards (badly formed docstrings will fail build tests):

   • numpydoc

   • reStructuredText (ReST)

5. The pull request should work for Python 3.7, 3.8, and 3.9 as well as raise test coverage. Pull requests are also checked for documentation build status and for PEP8 compliance.

   The build statuses and build errors for pull requests can be found at:

   https://github.com/Ouranosinc/xclim/actions

Warning

PEP8, black, pytest (with xdoctest) and pydocstyle (for numpy docstrings) conventions are strongly enforced. Ensure that your changes pass all tests prior to pushing your final commits to your branch. Code formatting errors are treated as build errors and will block your pull request from being accepted.

6. The version changes (HISTORY.rst) should briefly describe changes introduced in the Pull request. Changes should be organized by type (ie: New Indicators, New features and enhancements, Breaking changes, Bug fixes, Internal changes) and the GitHub Pull Request, GitHub Issue. Your name and/or GitHub handle should also be listed among the contributors to this version. This can be done as follows:

   Contributors to this version: John Jacob Jingleheimer Schmidt (:user:`username`).
   
   Internal changes
   ~~~~~~~~~~~~~~~~
   * Updated the contribution guidelines. (:issue:`868`, :pull:`869`).
   

   If this is your first contribution to Ouranosinc/xclim, we ask that you also add your name to the AUTHORS.rst, under Contributors.

Tips

To run a subset of tests, we suggest a few approaches. For running only a test file:

$ pytest xclim/testing/tests/test_xclim.py

To skip all slow tests:

$ pytest -m "not slow"

To run all conventions tests at once:

$ pre-commit run --all-files

Versioning

In order to update and release the library to PyPI, it’s good to use a semantic versioning scheme. The method we use is as follows:

major.minor.patch-release

Major releases denote major changes resulting in a stable API;

Minor is to be used when adding a module, process or set of components;

Patch should be used for bug fixes and optimizations;

Release is a keyword used to specify the degree of production readiness (beta [, and optionally, gamma]). Only versions built from the main development branch will ever have this tag!

An increment to the Major or Minor will reset the Release to beta. When a build is promoted above beta (ie: release-ready), it’s a good idea to push this version towards PyPi.

Deploying

A reminder for the maintainers on how to prepare the library for a tagged version.

Make sure all your changes are committed (including an entry in HISTORY.rst). Then run:

$ bumpversion <option> # possible options: major / minor / patch / release
$ git add *
$ git commit -m "Bumped version to v1.2.3-XYZ"

For PyPI releases/stable versions, ensure that the last version bumping command run is $ bumpversion release. These changes can now be merged to the main development branch:

$ git push

With this performed, we can tag a version that will act as the GitHub-provided stable source archive:

$ git tag v1.2.3-XYZ
$ git push --tags

Note

Starting from October, 2021, all tags pushed to GitHub will trigger a build and publish a package to TestPyPI by default. TestPyPI is a testing ground that is not indexed or easily available to pip. The test package can be found at: https://test.pypi.org/project/xclim/

Packaging

When a new version has been minted (features have been successfully integrated test coverage and stability is adequate), maintainers should update the pip-installable package (wheel and source release) on PyPI as well as the binary on conda-forge.

The Automated Approach

The simplest way to package xclim is to “publish” a version on GitHuh. GitHub CI Actions are presently configured to build the library and publish the packages on PyPI automatically.

Warning

Be warned that a published package version on PyPI can never be overwritten. Be sure to verify that the package published at https://test.pypi.org/project/xclim/ matches expectations before publishing a version on GitHub.

The Manual Approach

The manual approach to library packaging for general support (pip wheels) requires the following packages installed:

• setuptools

• wheel

• twine

From the command line on your Linux distribution, simply run the following from the clone’s main dev branch:

# To build the packages (sources and wheel)
$ python setup.py sdist bdist_wheel

# To upload to PyPI
$ twine upload dist/*

The new version based off of the version checked out will now be available via pip ($ pip install xclim).

Releasing on conda-forge

Initial Release

In order to prepare an initial release on conda-forge, we strongly suggest consulting the following links:

• https://conda-forge.org/docs/maintainer/adding_pkgs.html

• https://github.com/conda-forge/staged-recipes

Subsequent releases

If the conda-forge feedstock recipe is built from PyPI, then when a new release is published on PyPI, regro-cf-autotick-bot will open Pull Requests automatically on the conda-forge feedstock. It is up to the conda-forge feedstock maintainers to verify that the package is building properly before merging the Pull Request to the main branch.

Before updating the main conda-forge recipe, we strongly suggest performing the following checks:

• Ensure that dependencies and dependency versions correspond with those of the tagged version, with open or pinned versions for the host requirements.

• If possible, configure tests within the conda-forge build CI (e.g. imports: xclim, commands: pytest xclim)