MAINT: enhance the configuration for the pull-request-labeler workflow

[agriyakhetarpal]

Reference issue

Closes gh-19088

What does this implement/fix?

This PR configures the pull request labeler workflow to run just once on a PR, i.e., at the time of its opening – with no subsequent runs on further synchronisation events or updates to said PR. The new release of actions/labeler@v5 has fixed a previous issue where the sync-labels input was not correctly configured (please see actions/labeler#112). The permissions for the workflow have been moved to the job for security reasons, considering that this workflow will contain just a singleton job which needs those permissions.

Additional information

This PR uses the pull_request_target event and therefore might not run with the context of the changes here; however, I had tested and debugged my changes to see whether they will work and put together an explanation in a PR on my fork of SciPy: agriyakhetarpal#2

[agriyakhetarpal]

Hi @lucascolley – I have pushed the changes you suggested in #19088 (comment), and would appreciate a review!

[lucascolley]

thanks @agriyakhetarpal ! This LGTM, want to try merging @j-bowhay ?

The only part of the issue which this doesn't address is

Especially if reverted changes can be reflected that would be really nice

but I don't think it's worth trying to get that in now. I say we go with just labelling on opened for now and can look into that later if desired. It's quite rare that the amount of modules being touched decreases, and it's trivial to remove the labels manually.

[agriyakhetarpal]

I agree with you, I don't know of a method to do that currently... my initial guess of a way to do that would be to write another job that needs the label_pull_request job and notes changes to the labels provided on a PR (additions, deletions, etc.) using which it puts out a message printing what was changed. Personally not a fan of this though because it would just add to the noise for all those who are subscribed to a PR.

[j-bowhay]

@lucascolley I cant remember the history on this but I am not sure merging this will enable the CI job?

[lucascolley]

I cant remember the history on this but I am not sure merging this will enable the CI job?

Yeah there's another switch to flip somewhere as https://github.com/scipy/scipy/actions/workflows/pull-request-labeler.yml shows "disabled manually". Do you have permissions for that?

We'll want to merge this before re-enabling the workflow.

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x-ref #17116 (comment) for a possible follow-up as well as "if reverted changes can be reflected" as mentioned above

[agriyakhetarpal]

Not sure about the reverted changes one. But for

One possible point for further improvement would be to pick off the acronym (eg. MAINT) and map this to a label

This should be possible at this time by accessing the title of a PR (note: this would require that the PR should be opened with the title since this workflow is going to run just once). Another option could be to pick off these acronyms from the commit messages – we can re-use the [Build wheels] logic from the workflow for building wheels and base off on that.

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Please let me know what works, happy to debug on my fork!

[j-bowhay]

Ok let's try this, can always disable again. Let wait to see that everything works smoothly and then can consider the suggested follow up

[lucascolley]

thanks for your first contribution to SciPy @agriyakhetarpal !

[agriyakhetarpal]

And thanks for your support, it's much appreciated!

[j-bowhay]

Looks like something isn't working quite right, will disable for now to save resources
https://github.com/scipy/scipy/actions/runs/7304163132

[lucascolley]

Looks like we just need to update label-globs.yml, will submit a PR

[adityaraute]

Whoa, big one this