--- a/mercurial/copies.py	Sun Jan 31 13:43:33 2010 -0600
+++ b/mercurial/copies.py	Tue Feb 02 09:05:20 2010 +0100
@@ -154,7 +154,7 @@
                 break # no merge needed, quit early
             c2 = ctx(of, m2[of])
             cr = related(oc, c2, ca.rev())
-            if of == f or of == c2.path(): # non-divergent
+            if cr and (of == f or of == c2.path()): # non-divergent
                 copy[f] = of
                 of = None
                 break