Merge commits are failing length check

[statuscake-machine]

When a pull request is merged it will contain a subject message similar to the following:

Merge pull request #117 from Organisaiton/name-of-the-branch-being-merged

This is longer than the default 50 character limit. When the action runs on the main branch it fails.

[mristin]

Hi @statuscake-machine

Should we just ignore messages starting with Merge pull request #.* from .*?

[statuscake-machine]

I think that makes sense as these are outside the control of the user. Alternatively perhaps there is a way to detect if the commit was a merge commit? I'm not sure exactly the range of values that come from github.context.eventName but maybe merge is one of them?

[Fryuni]

Update on this. There is no way to detect for sure that a commit is a merge commit from just the event.

It is possible by making some API calls. For each commit in the push event we'd need to:

1. Make a request asking which PR introduced that commit¹
2. Check if the commit in question is the same as the merge_commit_sha of the PR
3. Check if the merge method was not a rebase merge, in which that value is just the last commit of the PR since there are no merge commits²

Footnotes

1. List pull requests associated with a commit ↩

2. Pull request ↩

[Fryuni]

A more generic approach would be to have a parameter to ignore commits whose title matches the given patterns. The default patterns for such a filter could be for matching GitHub's default merge commit title.

[mristin]

@Fryuni I think the pattern matching approach is far simpler and would generalize across Git repositories.

[Fryuni]

It took me a while to get back to this, but PR is open now. Also, @mristin, I think you can send the command for the dependabot's PRs to re-evaluate and close themselves since everything was updated on a single PR