diff -r 3d14c1217117 -r 0ca8410ea345 mercurial/revlog.py
--- a/mercurial/revlog.py	Sat May 16 09:03:21 2015 +0200
+++ b/mercurial/revlog.py	Sat May 16 11:28:04 2015 -0700
@@ -12,6 +12,7 @@
 """
 
 # import stuff from node for others to import from revlog
+import collections
 from node import bin, hex, nullid, nullrev
 from i18n import _
 import ancestor, mdiff, parsers, error, util, templatefilters
@@ -485,7 +486,7 @@
 
         # take all ancestors from heads that aren't in has
         missing = set()
-        visit = util.deque(r for r in heads if r not in has)
+        visit = collections.deque(r for r in heads if r not in has)
         while visit:
             r = visit.popleft()
             if r in missing: