graft: use proper revisions for copy detection (issue3265)

mercurial/commands.py

@@ -2601,7 +2601,7 b' def graft(ui, repo, *revs, **opts):'
             repo.dirstate.setparents(current.node(), nullid)
             repo.dirstate.write()
             # fix up dirstate for copies and renames
-            cmdutil.duplicatecopies(repo, ctx.rev(), current.node())
+            cmdutil.duplicatecopies(repo, ctx.rev(), ctx.p1().rev())
             # report any conflicts
             if stats and stats[3] > 0:
                 # write out state for --continue