copy: add experimental support for marking committed copies The simplest way I'm aware of to mark a file as copied/moved after committing is this: hg uncommit --keep <src> <dest> # <src> needed for move, but not copy hg mv --after <src> <dest> hg amend This patch teaches `hg copy` a `--at-rev` argument to simplify that into: hg copy --after --at-rev . <src> <dest> In addition to being simpler, it doesn't touch the working copy, so it can easily be used even if the destination file has been modified in the working copy. Differential Revision: https://phab.mercurial-scm.org/D8035

--- a/tests/test-rename-after-merge.t	Thu Dec 26 14:02:50 2019 -0800
+++ b/tests/test-rename-after-merge.t	Fri Dec 20 13:24:46 2019 -0800
@@ -120,10 +120,14 @@
   $ hg log -r tip -C -v | grep copies
   copies:      b2 (b1)
 
-Test unmarking copies in merge commit
+Test marking/unmarking copies in merge commit
 
   $ hg copy --forget --at-rev . b2
-  abort: cannot unmark copy in merge commit
+  abort: cannot mark/unmark copy in merge commit
+  [255]
+
+  $ hg copy --after --at-rev . b1 b2
+  abort: cannot mark/unmark copy in merge commit
   [255]
 
   $ cd ..