Contributing code#

This guide is intended for developers who wish to contribute to our codebase. Here’s how to set up a local development environment:

Setting up a development environment#

  1. Fork our repository on GitHub

  2. Locally clone your forked repository (replace your-username with your GitHub username):

    git clone{your-username}/scvi-tools.git
    # or with SSH
    git clone{your-username}/scvi-tools.git
    cd scvi-tools
  3. Add the main repository as a remote:

    git remote add upstream
  4. Install the development dependencies and the package in editable mode into a virtual environment with Python 3.9 - 3.11:

    pip install -e ".[dev]"
    # or with uv
    uv pip install -e ".[dev]"

    Don’t know how to set up a virtual environment? Check out our installation guide!

  5. (Optional) confirm that the installation was successful:

    pip show scvi-tools
  6. (Optional) Set up pre-commit git hooks:

    pre-commit install

    This will run pre-commit checks before each commit, including code formatting and linting. Alternatively, you can run the checks manually with:

    pre-commit  # check modified files
    # or
    pre-commit run --all  # check all files

Scoping changes#

Before you start working on a new feature or bug fix, we recommend opening an issue (if one does not already exist) to discuss the proposed changes. This will help ensure that your changes are aligned with the project’s goals and that you are not duplicating work.

We don’t guarantee that all changes will be accepted, but we will do our best to provide feedback and guidance on how to improve your contributions.

Adding code changes#

We only accept code changes that are made through pull requests. To contribute, follow these steps:

  1. Create a new branch for your changes:

    git checkout -b my-change
  2. Make your changes and commit them:

    git add .
    git commit -m "My change"
  3. (Optional) If your changes add a new feature or address an existing bug, we require that you add tests to cover the new code, which should be added under the tests directory.

    To run the tests, use:

    pytest  # run all tests
    # or
    pytest tests/  # run tests in a specific file
    # or
    pytest tests/  # run a specific test
  4. (Optional) If your changes add a new function or class to the public API, please include docstrings that describe the purpose, usage, and parameters of the new code, and update the API reference (docs/api) accordingly.

  5. Include a description of your changes in the release notes ( If you are unsure where to place your changes, please ask in the pull request.

  6. Push your changes to your fork:

    git push origin my-change
  7. Open a pull request on the main repository. Make sure to include a detailed description of your changes in the body and reference any related issues.

Standards and conventions#

  • We use ruff for formatting and linting Python files, which closely mirrors the Black code style.

  • We use Prettier for formatting YAML files.

  • We use Mdformat and markdownlint for formatting and linting Markdown files.

  • We use the numpydoc style for docstrings. All public functions and classes must have a docstring that describes their purpose, usage, and parameters.

  • Although not all parts of our codebase are type-annotated yet, we recommend that all new code be annotated with type hints according to the PEP 484 and PEP 526 guidelines.

  • We generally don’t commit data files, except if they are small and necessary for testing. This will be assessed on a case-by-case basis.

  • Starting from version 1.2, we format commits into the main branch according to Conventional Commits. Don’t worry if you’re not familiar with this convention as a maintainer will format any commits before merging into the main branch. For more details, see our maintenance guide.

  • Starting with version 0.20, we follow the Keep a Changelog convention for

  • We version our releases according to Semantic Versioning.