Code quality checks

Install and use cuML's pre-commit hooks to check formatting, lint, and spelling before submitting changes. CI runs the same hooks. The repository's .pre-commit-config.yaml is the source of truth for the configured checks, versions, and file selection.

For contribution requirements, see CONTRIBUTING.md.

Install pre-commit hooks

Install pre-commit in your development environment with either Conda or pip:

conda install -c conda-forge pre-commit

Alternatively:

pip install pre-commit

From the repository root, install the Git hooks:

pre-commit install

The hooks run automatically on staged files when you commit. Review any formatter changes, stage them, and retry the commit. If checks modify files again, repeat until they pass.

Run checks manually

From the repository root, check specific files while iterating:

pre-commit run --files path/to/changed_file.py path/to/another_file.md

To check all files:

pre-commit run --all-files

Some hooks inspect repository-wide configuration rather than only the selected files. Read the hook output, fix reported problems, and rerun the checks before requesting review. Formatting and lint checks do not replace the tests relevant to your change.

Clang-tidy

CI runs clang-tidy to detect potential C++ issues beyond the pre-commit checks. Running it locally is optional, but useful when investigating CI failures. Use either Docker or Conda on a Linux development machine with the build prerequisites described in BUILD.md. Run the commands below from the repository root.

Docker

Use the CI image matching the branch's cuML version (shown here for 26.12):

docker run --rm --pull always \
    --mount type=bind,source="$(pwd)",target=/opt/repo --workdir /opt/repo \
    -e SCCACHE_S3_NO_CREDENTIALS=1 \
    rapidsai/ci-conda:26.12-latest /opt/repo/ci/run_clang_tidy.sh

The CI script creates its environment, configures the build, and runs clang-tidy.

Conda

Choose an existing clang_tidy_*.yaml environment file from conda/environments/ matching your CUDA version and architecture. For example, on Linux x86_64 with CUDA 13.3:

conda env create -n cuml-clang-tidy \
    -f conda/environments/clang_tidy_cuda-133_arch-x86_64.yaml
conda activate cuml-clang-tidy
./build.sh --configure-only libcuml
python cpp/scripts/run-clang-tidy.py --config pyproject.toml

The configure step generates the compilation database used by clang-tidy.

Spelling checks

The hooks run codespell to check spelling. To interactively apply suggested fixes, install codespell in your development environment and run it from the repository root:

codespell --toml pyproject.toml -i 3 -w path/to/changed_file.md

Review suggested edits before committing. For false positives, use the narrowest appropriate exception:

• Ignore a specific line using a codespell inline directive.
• Add a legitimate project-wide term to ignore-words-list in the root pyproject.toml.
• Exclude a file from the codespell hook in .pre-commit-config.yaml only when checking the file is inappropriate, such as generated content.