CI: add slash dispatch workflow to trigger pre-commit checks with comment

[MarcoGorelli]

This would be an on-demand bot to run pre-commit checks on a PR, which can be triggered by commenting

@github-actions pre-commit

on a pull request (see here for a demo).

Use case: if a PR is submitted and is good-to-go except for some linting error, we can just comment /pre-commit-run and have the bot fixup the errors.

[jorisvandenbossche]

Cool, thanks!
That actually reminded me that we use something similar in the arrow repo, using comments to trigger actions: https://github.com/apache/arrow/blob/master/.github/workflows/comment_bot.yml. This seems to check the content of the comment, instead of using one workflow (with slash-command-dispatch) to trigger another, which seems a bit simpler to me?

[MarcoGorelli]

Thanks @jorisvandenbossche ! I didn't know you could do that, that indeed does look simpler, I'll see if I can update this to do it that way

[MarcoGorelli]

@jorisvandenbossche OK, done

If the comment-bot is now largely taken from arrow, my understanding is that we need to include their license at the top of the file - is this right?

[jorisvandenbossche]

If the comment-bot is now largely taken from arrow, my understanding is that we need to include their license at the top of the file - is this right?

I don't think that that is necesaarily needed in this case. I mean, I contribute to several projects, and I am constantly applying what I tried / learned how to set up github actions in one project to other projects. Also, if you include the license, you would need to clearly state what has changed. And in the end, the main thing you copied is the line if: startsWith(github.event.comment.body, '@github-actions autotune') and the idea to use the pr-push action, for the rest it's a lot different compared to the original file from arrow.

[jorisvandenbossche]

Thanks for the update!

[jorisvandenbossche]

Suggested change

	- name: install-pre-commit
	- name: Install pre-commit

(to be consistent with other names)

[jorisvandenbossche]

I would maybe keep a "pre-commit" specific command

(we can always later have other bot actions, and name something combined "autotune", but for now it's just pre-commit)

[jorisvandenbossche]

Does this use the author of the last commit on the PR as commiter here?

Maybe your original "github actions" user is more transparent in who commited it?

      git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
      git config --local user.name "github-actions[bot]"
      git commit -m "Run pre-commit" -a

[jorisvandenbossche]

Actually, using the PR author / last commiter as commit author here is maybe good. That avoids that github wants to add the bot to the "Co-authored-by", which is not needed.
A "[automated commit]" in the commit message should be clear enough about the origin of the change.

[jorisvandenbossche]

I would also keep your original message here, something more specific to pre-commit

[jorisvandenbossche]

What are your thoughts on #38444 (comment) ?

[MarcoGorelli]

Hey Joris - sorry, I missed that comment, somehow my brain only registered the review comments - I've removed the license header as I think your assessment makes perfect sense (as someone with far less experience, I was trying to tread carefully)

[jreback]

this looks fine to me. let's give it a try.

[jreback]

@MarcoGorelli can you add somewhere the various actions that are availabel (take is in the user docs, but this one plus the backport ones could go somewhere)

[jorisvandenbossche]

Thanks!