mercurial/revset.py

--- a/mercurial/revset.py	Thu Mar 13 15:00:34 2014 -0500
+++ b/mercurial/revset.py	Mon Mar 10 10:49:04 2014 -0700
@@ -2340,6 +2340,9 @@
     def __contains__(self, x):
         return x in self._r1 or x in self._r2
 
+    def set(self):
+        return self
+
 class _generatorset(object):
     """Wrap a generator for lazy iteration