Thanks for your interest in contributing to hydra-zen! Please read through the following resources before you begin working on any contributions to this code base.
- Installing hydra-zen for development
- Installing hydra-zen for development (using uv)
- Configuring Your IDE
- Adding New Features to the Public API
- Running Our Tests Manually
- Running Tests Using
tox - Formatting
- Documentation
- Releasing a New Version of hydra-zen
Install the toolkit along with its test dependencies; checkout the repo, navigate to its top level and run
pip install -e .the -e option ensures that any changes that you make to the project's source code will be reflected in your local install – you need not reinstall the package in order for your modifications to take effect.
If your contributions involve changes to our support for NumPy, PyTorch, PyTorch-Lightning, JAX, pydantic, or beartype then you will need to install those dependencies as well, in order for our tests-against-third-parties to run locally in your environment.
uv is a modern, fast Python package manager that provides significantly faster dependency resolution and installation compared to pip. It's recommended for contributors who want a streamlined development experience.
Install uv using the standalone installer:
curl -LsSf https://astral.sh/uv/install.sh | shOr on Windows (PowerShell):
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"Or via pip:
pip install uvOnce uv is installed, navigate to the top level of the hydra-zen repository and run:
uv syncThis command will:
- Create a virtual environment (
.venv) if one doesn't exist - Install hydra-zen in editable mode
- Install all development dependencies (test, formatting, linting, etc.)
- Generate a
uv.lockfile for reproducible installs
The uv.lock file ensures that all contributors use identical dependency versions, preventing "works on my machine" issues.
With uv, you don't need to manually activate the virtual environment. Use uv run to execute commands:
# Run tests
uv run pytest tests/
# Run tests in parallel
uv run pytest tests/ -n auto
# Run a specific test file
uv run pytest tests/test_builds.py
# Run tox environments
uv run tox -e py313
uv run tox -e format
uv run tox -e coverageFormat code using the same tools as the CI:
# Auto-format code (uses black, isort, autoflake)
uv run tox -e format
# Or run formatting tools directly
uv run black src/ tests/
uv run isort src/ tests/uv run pre-commit install
uv run pre-commit run- Speed: 10-100x faster dependency resolution and installation
- Reproducibility:
uv.lockensures identical environments across machines - Convenience: No need to activate virtual environments with
uv run - Single source of truth: hydra-zen uses PEP 735 dependency groups, which means development dependencies are defined once and shared between
uvandtox
The project defines several dependency groups in pyproject.toml:
test: pytest, hypothesis, and testing toolsformat: black, isort, autoflake (exact versions pinned)lint: flake8, codespell, and linting tools (exact versions pinned)coverage: coverage measurement toolsdev: All development dependencies (includes all groups above)
The format and lint groups use exact version pins to ensure formatting and linting are consistent across all contributors and CI. These are the single source of truth used by both uv and tox environments.
Using tox (recommended for full test suite):
# Test against a single Python version (auto-downloads if needed)
uv run tox -e py39
# Test against multiple versions in parallel
uv run tox -p -e py39,py310,py313
# List all available tox environments
uv run tox -aUsing custom venvs (for interactive work or specific tests):
# Create a Python 3.9 venv
uv venv --python 3.9 .venv-py39
# Activate it and install dev dependencies
source .venv-py39/bin/activate # or .venv-py39\Scripts\activate on Windows
uv pip install -e . --group dev
# Run specific tests or use the REPL
pytest tests/test_builds.py
python # Interactive Python 3.9 REPL
# Or run without activating
uv run --python 3.9 pytest tests/test_builds.py
uv run --python 3.9 python # REPL with Python 3.9The uv.lock file pins exact versions of all dependencies (including transitive dependencies) to ensure reproducible environments. It should be updated periodically to pick up bug fixes and security patches.
When to update:
- Before starting work on a new feature (get latest compatible versions)
- After updating version constraints in
pyproject.toml - Periodically (e.g., monthly) to stay reasonably current
- When a security vulnerability is announced in a dependency
How to update:
# Update all dependencies to latest compatible versions
uv sync --upgrade
# Update a specific package
uv sync --upgrade-package pytest
# After updating, run tests to ensure everything still works
uv run pytest tests/ -n auto
# If tests pass, commit the updated lockfile
git add uv.lock
git commit -m "Update dependencies"Updating pinned tools (ruff, etc.):
The format and lint dependency groups use exact version pins. To update these:
- Edit
pyproject.tomland update the version (e.g.,ruff==0.8.5) - Run
uv syncto update the lockfile - Run
uv run tox -e formatanduv run tox -e enforce-formatto verify - Commit both
pyproject.tomlanduv.lock
Best practices:
- Always run the full test suite after updating dependencies
- Review the changelog of updated packages for breaking changes
- Update dependencies in a separate commit/PR from feature work
- If a dependency update breaks tests, investigate before proceeding
hydra-zen utilizes pyright to validate its interfaces. Thus it is recommended that developers use an IDE with pyright language server.
VSCode's Pylance extension is built off of pyright, and thus is recommended. If you use VSCode with the Pylance, then make sure that Type Checking Mode is set to basic for your hydra-zen workspace. Your IDE will then mark any problematic code.
All functions/classes that are part of the public API must have a docstring that adheres to the numpy docstring style, and the docstring must include and Examples section. The function's docstring must be scanned by pyright, by adding the function to this test.
All publicly-facing interfaces must be type-annotated and scan "clean" using the pyright type checker.
The CI for hydra-zen requires 100% code coverage, thus all new features will need to be tested appropriately. We use the pytest framework for collecting/running/reporting tests and are keen on using the Hypothesis library for writing property based tests where appropriate.
See the section on tox for details.
Install the latest version of pytest and hypothesis:
pip install pytest hypothesisNavigate to the top-level of hydra-zen and run:
pytest tests/tox is a tool that will create and manage a new Python environment where it can then run hydra-zen's
automated tests against various Python versions and dependencies.
Install tox:
pip install toxOr with uv:
uv pip install tox tox-uvNote: hydra-zen uses tox-uv for faster environment creation and dependency resolution. The tox environments are configured to use PEP 735 dependency groups, which means the test dependencies in tox environments are automatically synchronized with the dependency groups defined in pyproject.toml.
List the various tox-jobs that are defined for hydra-zen:
tox -aThen, run the job of choice using:
tox -e [job-name]Our CI requires that our tests achieve 100% code coverage. The easiest way to measure
code-coverage is by using tox:
tox -e coverageThis will produce a coverage report that indicates any lines of code that were note covered by tests.
Our CI runs the pyright type-checker in basic mode against hydra-zen's entire code base and against specific test files. It also requires a type completeness score of 100%; this ensures that the type-annotations for our public API are complete and accurate. Lastly, we run some rudimentary tests to assess basic mypy compatibility.
You can run these static type checking tests locally using tox via:
tox -e typecheckhydra-zen's CI requires that black, isort, and flake8 can be run against src/ and tests/ without any diffs or errors. To run this test locally, use
$ tox -e enforce-formatTo locally format/fix code issues caught by this stage of our CI, run:
$ tox -e formatThat being said, it is recommended that you install pre-commit hooks that will apply these formatters to the diffs of each commit that you make. This is substantially faster and more streamlined that using the tox solution.
We provide contributors with pre-commit hooks, which will apply auto-formatters and linters to your code before your commit takes effect. You must install these in order to contribute to the repo.
First install pre-commit in your Python environment. Run:
pip install pre-commitThen, in the top-level of the hydra_zen repo, run:
pre-commit install
pre-commit runGreat! You can read more about pre-commit hooks in general here: https://pre-commit.com/
Our pre-commit hooks run the following auto-formatters on all commits:
It also runs flake8 to enforce PEP8 standards.
Running
tox -e docswill build the docs as HTML locally, and store them in hydra_zen/.tox/docs/html. See the docs/README.md in this repo for details.
We use GitHub Actions to handle building and publishing our docs. The job runs Sphinx and commits the resulting artifacts to the gh-pages branch, from which GitHub publishes the HTML pages.
The documentation is updated by each push to main.
hydra-zen uses semantic versioning and the Python package extracts its version from the latest git tag (by leveraging setuptools-scm). Suppose we want to update hydra-zen's version to 1.3.0; this would amount to tagging a commit:
$ git tag -a v1.3.0 -m "Release 1.3.0"
$ git push origin --tagsNothing needs to be updated in the Python package itself.
We utilize GitHub Actions to publish to PyPI. Once the tag has been pushed to GitHub, draft a new release on GitHub with the correct associated tag, and the new version will automatically be published to PyPI.
Before releasing a new version of hydra-zen, make sure to add a new section to the changelog.