I'm aware that Gerrit uses change-id to determine if a commit is only a new patch-set from an existing review or should be shown as a new review. But what if I push a commit with the same change-id of another commit that is already merged? AFAIK, a merged commit cannot be brought back to review so I assume it will create a new review, but that goes against another assumption I have, that the pair change-id + branch is an unique identifier of a review.
I don't have access to a running instance of Gerrit right now, so I can't test it. Does anyone know what happens in this case? If case a new review is created, is there an unique identifier of a specific review?
The push gets rejected when you commit a change with the same change-id into the same branch of the same project:
[remote rejected] (change # closed)