GitHub Action to run pre-commit on all pull requests

[cclauss]

This ensures that if a contributor fails to install pre-commit locally, CI will still highlight any issues in their submissions.

[akaihola]

This makes most sense if we move all checks from the workflow to pre-commit, and just run pre-commit from the workflow, right?

I'm a bit torn on this, since I also like GitHub Actions showing each different check as a separate item in the UI. Is there any way to make that still happen when doing the checks within pre-commit?

[cclauss]

You understand well -- I too am torn about how to implement this but I tend to put the fastest checks in pre-commit and the slower checks in a separate GitHub Action.

https://pre-commit.ci is supercool because it allows for automatic corrections to be committed back to the PR but that is a whole other CI tool to consider.

[akaihola]

pre-commit documentation describes the pre-commit run option [hook-id]:

Options:

• [hook-id]: specify a single hook-id to run only that hook.

Some example useful invocations:

• [...]
• pre-commit run flake8: run the flake8 hook against all staged files.

Using that option, we could still run each check as their own step in the GitHub Workflow, while in developers' environments git-commit would run them all.

That would of course require remembering to add new checks also to the workflow after adding them to the pre-commit configuration.

[cclauss]

I find the pre-commit output to be quite readable and have never had any contributor complaints about not understanding that output.

[akaihola]

For the 1.5.0 version, we'll keep running checks directly from GitHub workflows. Let's consider pre-commit in 1.6.0. Thanks again @cclauss!

[akaihola]

I've been experimenting with some GitHub actions which annotate the Files changed view of the pull request with messages from linters and checkers.

To combine that with a good pre-commit setup for local use, it seems to me that at least some configuration needs to be duplicated, which is a bit of a bummer.