copies: fix duplicatecopies() with overlay context

The reasoning for this check is in 78d760aa3607 (duplicatecopies: do
not mark items not in the dirstate as copies, 2013-03-28). The check
was then moved to workingfilectx in 754b5117622f (context: add
workingfilectx.markcopied, 2017-10-15) and no corresponding check was
added later when overlayworkingfilectx was added. Rather than adding
the check there, this patch adds a more generic check on the callers
side and removes the check in workingfilectx.markcopied().

Differential Revision: https://phab.mercurial-scm.org/D6380

mercurial/context.py

@@ -1773,8 +1773,7 b' class workingfilectx(committablefilectx)'
 
     def markcopied(self, src):
         """marks this file a copy of `src`"""
-        if self._repo.dirstate[self._path] in "nma":
-            self._repo.dirstate.copy(src, self._path)
+        self._repo.dirstate.copy(src, self._path)
 
     def clearunknown(self):
         """Removes conflicting items in the working directory so that

mercurial/copies.py

@@ -798,4 +798,5 b' def duplicatecopies(repo, wctx, rev, fro'
     for dst, src in pathcopies(repo[fromrev], repo[rev]).iteritems():
         if dst in exclude:
             continue
-        wctx[dst].markcopied(src)
+        if dst in wctx:
+            wctx[dst].markcopied(src)

tests/test-rebase-inmemory.t

@@ -795,12 +795,10 b' Rebase across a copy with --collapse'
   $ hg co -q 0
   $ echo a2 > a
   $ hg ci -qm 'modify a'
-BROKEN: obviously...
   $ hg rebase -r . -d 1 --collapse
   rebasing 2:41c4ea50d4cf "modify a" (tip)
   merging b and a to b
-  abort: a@b977edf6f839: not found in manifest!
-  [255]
+  saved backup bundle to $TESTTMP/rebase-rename-collapse/.hg/strip-backup/41c4ea50d4cf-b90b7994-rebase.hg
   $ cd ..
 
 Test rebasing when the file we are merging in destination is empty