test: demonstrate crash with in-memory rebase and copies In the added test case, there is a merge commit that has one obsolete parent with a rename. Since the rename is not in the other parent, pathcopies() from that other parent will include the copy. Then when we try to rebase this merge commit onto another commit that has the same content changes, but no tracking of the rename (because it was done with "hg remove; hg add" instead of "hg mv"), we try to propagate the copy information. That fails because overlayworkingctx expects a file to be modified if it's going to have copy information. Differential Revision: https://phab.mercurial-scm.org/D6132