nodesbetween: fix a bug with duplicate heads

mercurial/revlog.py

@@ -599,12 +599,12 b' class revlog(object):'
             if not heads:
                 return nonodes
             ancestors = {}
-            # Start at the top and keep marking parents until we're done.
-            nodestotag = heads[:]
             # Turn heads into a dictionary so we can remove 'fake' heads.
             # Also, later we will be using it to filter out the heads we can't
             # find from roots.
             heads = dict.fromkeys(heads, 0)
+            # Start at the top and keep marking parents until we're done.
+            nodestotag = heads.keys()
             # Remember where the top was so we can use it as a limit later.
             highestrev = max([self.rev(n) for n in nodestotag])
             while nodestotag:

tests/test-bundle-r

@@ -72,6 +72,10 b' hg -R test bundle --base 2 -r tip test-b'
 hg -R test bundle --base 2 -r 7 test-bundle-branch2.hg
 hg -R test bundle --base 2 test-bundle-all.hg
 hg -R test bundle --base 3 -r tip test-bundle-should-fail.hg
+
+# issue76 msg2163
+hg -R test bundle --base 3 -r 3 -r 3 test-bundle-cset-3.hg
+
 hg clone test-2 test-9
 cd test-9
 echo % 2