Use GitHub Actions to automatically label Pull Requests

[ericcornelissen]

Issue: None

Checklist

n/a

Description

We got access to GitHub Actions a while back when it was still beta-access only but unfortunately haven't used it yet (we initially wanted to use it for #982) and I want to start using it to implement some stuff, among others #2380 and simple-icons/simple-icons-font#1. However, I decided to start with something that is a bit simpler, namely:

Feature: Adding the labels new icon and updated icon to Pull Requests automatically based on the files added or changed in the Pull Request.¹

For those unfamiliar with GitHub Actions the file .github/workflows/pull_requests.yml defines a "workflow", which is analogous to a build defined in .travis.yml. In it I say that on: [pull_requests] I want to do some stuff, run one or more "actions", namely I want to run(s-)on: ubuntu-latest a step as defined by ericcornelissen/labeler@master. In the case of the "action" is configured by .github/labeler.yml (which is a hard requirement from the "action" itself). The (currently incomplete) documentation for the configuration can be found in the project's README.

I tested the workflow in my fork of this repository, you can see the final results in this Pull Request and this Pull Request (and a bunch more attempts in the list of closed Pull Requests). Also, the action should run on this Pull Request, but it does nothing as the files changed don't match the globs in the configuration. Based on this article it looks like the actions won't start running until this is merged because this PR is coming from a fork (rather than this repo) so I hope it will start working 🤞

Why do this with GitHub Action rather than Travis CI? To try it out and learn, but also because I think it is easier to use and work with especially when you want to do stuff like in #2380. We don't need to move our Travis CI builds to GitHub Actions, but we could do that as well. Also, I like it very much that all the configuration is in the .github/ directory 🙃

PS. I'm using my personal fork of actions/labeler (namely ericcornelissen/labeler) because I could not any labeling action that checked whether a file was added or changed (or removed for that matter). I do have an open issue regarding this feature to see if there is more interest, if so it may get merged and then we can update this action accordingly.

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^{1: I would personally have preferred if multiple PR templates was a thing, just like multiple Issue templates are...}

[runxel]

That's cool! Had that on my bucket list as well :)

[runxel]

Since nobody complains we can merge this nice thing in 😎
Thanks @ericcornelissen!

[runxel]

Uuuh, .... somethings wrong, @ericcornelissen 😨
Please have a look

[ericcornelissen]

I had noticed this already, seems to be the problem discussed in actions/labeler#12 😞 I'm trying to find a solution, if I can't find anything I will Revert this Pull Request...

Anyway, for now you can merge a Pull Request where this error occurs if you want. It's not pretty but it's fine 👍

[runxel]

Ach, what a shame.
Then let's hope the mprovement of yours gets some attention and will be included upstream.

[ericcornelissen]

I will be reverting this PR as I can't find a solution at the moment nor think of a suitable solution. I might try to convert my solution into a Probot or we can use this bot if it can suite our needs.

Then let's hope the improvement of yours gets some attention and will be included upstream.

That would be nice nonetheless 🙂 though I suspect our use case is quite niche