--- a/mercurial/revset.py	Wed Jun 10 19:58:27 2015 -0700
+++ b/mercurial/revset.py	Tue Jun 16 19:47:46 2015 -0700
@@ -1107,8 +1107,9 @@
     # i18n: "head" is a keyword
     getargs(x, 0, 0, _("head takes no arguments"))
     hs = set()
+    cl = repo.changelog
     for b, ls in repo.branchmap().iteritems():
-        hs.update(repo[h].rev() for h in ls)
+        hs.update(cl.rev(h) for h in ls)
     # XXX using a set to feed the baseset is wrong. Sets are not ordered.
     # This does not break because of other fullreposet misbehavior.
     # XXX We should not be using '.filter' here, but combines subset with '&'