operations: Remove check for specific error message

In UserMergeBranch we're verifying whether the error message returned by
`gitaly-git2go` contains a specific string to be able to discern the
case where the merge failed because of a merge conflict. This check is
not required anymore though given that we now always get a specific
`ConflictingFilesError{}` in that case.

Remove the check to clean up the logic.

1 files changed, 2 insertions, 1 deletions

diff --git a/internal/gitaly/service/operations/merge.go b/internal/gitaly/service/operations/merge.go
index c15ef49ac..b15c63867 100644
--- a/internal/gitaly/service/operations/merge.go
+++ b/internal/gitaly/service/operations/merge.go
@@ -85,10 +85,11 @@ func (s *Server) UserMergeBranch(stream gitalypb.OperationService_UserMergeBranc
 			return helper.ErrInvalidArgument(err)
 		}
 
-		if strings.Contains(err.Error(), "could not auto-merge due to conflicts") || errors.As(err, &git2go.ConflictingFilesError{}) {
+		if errors.As(err, &git2go.ConflictingFilesError{}) {
 			return helper.ErrFailedPreconditionf("Failed to merge for source_sha %s into target_sha %s",
 				firstRequest.CommitId, revision.String())
 		}
+
 		return helper.ErrInternal(err)
 	}