pre-commit hooks

When you enter the development environment, our pre-commit.hook script is symlinked in your local git repository as .git/hooks/pre-commit, serving as the Git pre-commit hook.

When you make a git commit, the following happens:

  • The pre-commit.hook script runs the (confusingly named) pre-commit tool in the flatpak sandbox.

  • The pre-commit tool runs the hooks configured in .pre-commit-config.yaml

Sooner or later you'll want to update the pre-commit framework and its hooks.

How to update the pre-commit tool

The pre-commit tool is installed in the flatpak sandbox through python3-pre-commit.json. The python3-pre-commit.json file is generated with flatpak-pip-generator. See the instructions for updating the Python dependencies.

How to update the hooks

The .pre-commit-config.yaml file contains the list of hooks we use, grouped by the git repo in which they can be found. The repos are downloaded and cached by the pre-commit tool on demand. These hooks are executed each in their own own virtualenv.

A special case is the local repo which groups the hooks installed alongside the pre-commit framework, in the sandbox. We only need the pylint hook to be run in the sandbox instead of in its own virtualenv, such that it has access to the Python environment in the sandbox.

To update pylint, follow the instructions for updating the Python dependencies.

To update the regular hooks, take the repos one by one, check what is the latest version and update the entry in the .pre-commit-config.yaml file. After updating each repo, validate the entire codebase and fix all the newfound errors.

For example, suppose we just updated the repo to revision v3.4.0:

  - repo:
    rev: v3.4.0
      - id: check-yaml

To run the check-yaml hook on the entire codebase:

(ptv-flatpak) $ ptvenv pre-commit run -a check-yaml

If you feel brave, you can use pre-commit itself to update the hooks:

(ptv-flatpak) $ ptvenv pre-commit autoupdate

At the end, do a final check by running all the hooks on the entire codebase:

(ptv-flatpak) $ ptvenv pre-commit run -a

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