Hook failure leaves MR in confusing state

I use a post-receive hook on my git repo to mirror the repo to another server. Upon upgrade to v8.0.1, the post-receive hook started exit 1 (due to a change in the new version of git in the omnibus package). Since it is a post-receive hook, the branch would merge without issue, but the hook would fail and send the MR back to reopened status. There was no logging on this and we spent a lot of time debugging the issue. It would be nice to see a comment on the MR mentioning the failure as a reason for sending it back to reopened.

I worked with @brandonrdunne on trying to debug this issue. I just wanted to add that what you do see is the commit reference in the MR and in activity you see the push to the merged branch, but nothing after that. Mergers see it and just keep trying to merge over and over not knowing why it failed.

Repository#merge calls commit_with_hooks which will commit and then return false if the post-receive hook fails. This bubbles up to MergeService#commit and then up to MergeService#execute. The code gets to the error state, thus never running the PostMergeService and never moving the state to merged, but we never see that error string anywhere. Then, because it's in :locked state, but never moved to :merged, in_locked_state's ensure block moves it back to :reopened

This is pretty easy to verify by just creating a simple custom_hooks/post-receive that does an exit 1

Hi @brandonrdunne,

First of all, thank you for raising an issue to help improve the GitLab product. We're sorry about this, but this particular issue has gone unnoticed for quite some time. To establish order in the GitLab-CE Issue Tracker, we must ensure that every issue is correctly labelled and triaged, to get the proper attention.

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• Unlabelled
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• It's not associated with a particular milestone

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Status changed to closed

Added ~761915 label

mentioned in merge request !14785