Use github wf to add module labels for PR based on file changes

[pseudo-nymous]

Description

Adds a new bot to automate labelling of pull requests with module tags based on file changes.
This bot uses .github/labeler.yml file to maintain mapping for module labels to corresponding regex paths to track.

This workflow is triggered using pull_request_target event which provides necessary write permission for adding labels to PRs. More details around this event: StackOverflow

Testing

Tested changes by creating pr on my own fork. pseudo-nymous#2

Further testing with sync flag: pseudo-nymous#3

Closes #13897

[github-actions]

This PR has not had activity in the past 2 weeks, labeling it as stale. If the PR is waiting for review, notify the [email protected] list. Thank you for your contribution!

[stefanvodita]

@pseudo-nymous, I'm only seeing this now, sorry! At first glance, it matches what I had in mind - thank you for addressing that issue! I'll do an in-depth review soon, but I'd appreciate others' thoughts as well. One potential concern is our GitHub action budget - do you have a sense of the cost of this workflow?

[stefanvodita]

This is great @pseudo-nymous! I left minor comments that I would like to see addressed, but this is very good already. I retract my concern about the action budget. This is running when a PR is created or updated, which is not that often.

[pseudo-nymous]

Did further testing with new sync flag, change is working as expected.
Ref: pseudo-nymous#3

[pseudo-nymous]

This is great @pseudo-nymous! I left minor comments that I would like to see addressed, but this is very good already. I retract my concern about the action budget. This is running when a PR is created or updated, which is not that often.

Thanks.

Yes, this bot is only triggered when when pr is created or updated.

I have addressed all the comments. Please take a look.

[stefanvodita]

Thank you for responding to the comments so quickly! I've one more small thing to add and if that's sorted I'll leave it a few days to see if others have feedback, then merge.

[mikemccand]

Wow, this looks really awesome! I wish we could retroactively apply it to PRs missing their module labels ... but let's start with this change (so new PRs are labeled).

[stefanvodita]

Thank you for this contribution @pseudo-nymous, I merged it just now and I'm really looking forward to see the first PR using it!

[pseudo-nymous]

Thanks.

I checked if same script could be used to label older PRs but there is no such event corresponding to already closed PR.
Maybe we can write an individual script which could process already closed PRs and label them. I will further explore on this.

[stefanvodita]

Brilliant! Let us know if you find anything. If you're interesting in this area of GitHub workflows / community tools, there are a few others that would be great to do:

1. Create a bot to check if there is a CHANGES entry for new PRs #13898
2. Create a bot to add milestones to new PRs #14190
3. Create a community metrics dashboard #13896

[pseudo-nymous]

I'll be happy to work on these. Thanks!

[stefanvodita]

I've seen new PRs get labels assigned. I like how it's working!