[Bug 58595] gitlab fails to run rebase builds due to missing contributor name

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=58595

--- Comment #2 from Patrick Hibbs  ---
Got it. It looks like that merge commit was made by the gitlab UI, it didn't
exist in my local tree, and rebasing on my local system and force pushing it
allowed the build to succeed. (with the flaky test failures.)

Maybe the Git Tutorial should be updated to warn people not to use the gitlab
UI when rebasing an MR? There's nothing mentioned about gitlab's UI causing
failures.