Display clear indication that merge request cannot be merged

Problem to solve

It is easy to miss that your MR has a merge conflict and so cannot be merged, until you try to actually merge the MR. This becomes a problem when you assign an MR to another person to review and merge and they cannot do so until the conflicts are fixed.

Intended users

Further details

A message appears on the MR page, near the Merge button, but there is so much information around it that it is easy to miss the message.

Proposal

Maybe we can provide a clear visual signal that the MR cannot be merged for some reason. That would cause the user to check what is preventing the MR from being merged, and they would then see the merge conflict message.

The visual indication could be something like an icon near the title of the MR, or a different color to the "Open" tag (usually green) near the title.

Availability & Testing

What does success look like, and how can we measure that?

A user can tell that an MR cannot be merged the moment they open the merge request.