[Github] Check code formatting sometimes gets stuck on checking out merge base

[boomanaiden154]

There are several code formatting jobs that are getting stuck on checking the repository out through the merge base. Not really sure why this is, potentially because it keeps trying to pull more commits and doesn't get anywhere. Jobs:

1. https://github.com/llvm/llvm-project/actions/runs/7671078679
2. https://github.com/llvm/llvm-project/actions/runs/7672038528
3. https://github.com/llvm/llvm-project/actions/runs/7672167981
4. https://github.com/llvm/llvm-project/actions/runs/7673145120
5. https://github.com/llvm/llvm-project/actions/runs/7673265818
6. https://github.com/llvm/llvm-project/actions/runs/7673558489

[boomanaiden154]

Copied two of the branches that still exist to my fork so that I hopefully can reproduce:

1. https://github.com/boomanaiden154/llvm-project/tree/code-formatting-stuck-1
2. https://github.com/boomanaiden154/llvm-project/tree/code-formatting-stuck-2

[nicovank]

I think this is happening when a branch and PR are updated before the previous job finished / properly started. Then it stays stale for some reason (Maybe a bug in the checkout action?). Recent examples manually going through the list of actions for this workflow:

1. failed (12:01PM), success (12:02PM)
2. failed (11:34AM), success (11:36AM)
3. failed (11:26AM), success (11:27AM)
4. failed (8:56AM), success (8:57AM)

Maybe worth trying:

concurrency:
  # This workfow must remain PR-only, or this group edited.
  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
  cancel-in-progress: true

[boomanaiden154]

Thank you very much for the triage!

I think I see what's happening. All of the failed actions seem to have come from force pushes. The timeouts happen when we try and checkout through the merge base. What I'm guessing happens is that if the user force pushes while we're trying to check out through the merge base, then when we deepen, we pull from the new ref, and we never get a common merge base because stuff has changed.

Might be incorrect, but a somewhat reasonable hypothesis.

Setting concurrency groups should fix that, and should be done anyways because it makes no sense to run the code formatting job on an outdated version of the code.

[nicovank]

Seems like a reasonable explanation to what's happening, hopefully this fixes it 👍 Thanks!

[boomanaiden154]

This has been fixed for a while.