Cancel workflows when one of them fail on temporary branch

[andrzejressel]

Hi,

I'm currently using max_checks_retries in my project and I've noticed that when one GH Actions job fails, new branch is immediately opened, but the old jobs are still running. For example:

andrzejressel/pulumi-gestalt#2293 (comment)

First branch was closed pretty fast (after 4 minutes), but the jobs were still running. It's an issue in my example, because I have ~140 jobs and I'd rather have them all cancelled if the current temporary mergify.io branch won't be merged anyway.

[jd]

Hi! Mergify does close the draft PR and delete its branch before starting the retry, so from the engine side the old ref is gone. The catch is that GitHub Actions does not automatically cancel in-progress workflow runs when the branch they were triggered on is deleted — push-triggered runs in particular keep going until they finish on their own.

The standard fix is to add a concurrency group to your workflow keyed by the ref, with cancel-in-progress: true:

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

With that in place, when Mergify recreates the temporary branch for the retry (same ref name), GitHub Actions will cancel the previous run on that ref instead of letting your 140 jobs run to completion.