copies: detect files as `touched/salvaged` if they only existed on one side The file cannot be merged if there was content to merge on the other side. So the previous record was wrong. In the general case, the file existed only on one side and got touched during the merge. So it should detected as touched. They are a special case where the merge manually prevent the file to be deleted. In this case the file is marked as `salvaged`. The result of this `salvaged` recording, copy-tracing-wise, is the same as recording it as `merged`. This is probably why they were recorded as `merged` in the first place. Differential Revision: https://phab.mercurial-scm.org/D10219