Gitlab lock error message refers to issue instead of MR

[sarcasticadmin]

Description

Gitlab has a separate identifier and counter for issues (represented by "#") vs merge requests (represented by "!") in comments. This is unlike Github were the issues and pull requests have the same identifier (represented by "#") and counter. Currently in Gitlab if one terraform root directory is locked by a plan and another MR comes in for the same root directory Atlantis response with the lock message but it points to an issue ("#") instead of the actual MR ("!"). As seen by the following screenshot:

The good new is the MR number is correct but it appears that the string formatting in the error is just assuming #: https://github.com/runatlantis/atlantis/blob/master/server/events/project_locker.go#L66

Expected Behavior

• Lock message would show !199 instead of #199 for Gitlab

System Info

$ atlantis version
atlantis 0.10.2

[lkysow]

Nice find, want to create a fix?

You'll need to change the signature of TryLock to also accept a VCSHostType argument, then pass this in from where it gets called and then change the TryLock function to detect if it's GitLab and use a different reference string.

[sarcasticadmin]

@lkysow sure Ill give it a go, thanks for providing info on the approach

[sarcasticadmin]

@mcdafydd @EppO thanks for knocking this out! Hadnt had a chance to dive into it but looking forward to testing this out!