#
#
# patch "viewmtn.py"
#  from [75ad31c8141502043ddff17960a31c70c2fc860b]
#    to [8a54d4050ede460fd91b87b0f0ec5e64dd373b18]
#
============================================================
--- viewmtn.py	75ad31c8141502043ddff17960a31c70c2fc860b
+++ viewmtn.py	8a54d4050ede460fd91b87b0f0ec5e64dd373b18
@@ -370,10 +370,11 @@ class BranchChanges:
             new_to_parent = set()
             for rev in to_parent:
                 # we must be cautious; we only want to look at parents on our branch!
-                for rev in parents:
-                    if rev == None or not on_our_branch(rev):
+		parents = filter(None, ops.parents(rev))
+                for parent_rev in parents:
+                    if rev == None or not on_our_branch(parent_rev):
                         continue
-                    new_to_parent.add(rev)
+                    new_to_parent.add(parent_rev)
             if len(new_to_parent) == 0:
                 # out of revisions...
                 break