mercurial/phases.py

--- a/mercurial/phases.py	Tue Jun 16 16:15:15 2015 -0400
+++ b/mercurial/phases.py	Mon Jun 15 15:52:52 2015 -0700
@@ -167,6 +167,7 @@
         ph.dirty = self.dirty
         ph.opener = self.opener
         ph._phaserevs = self._phaserevs
+        ph._phasesets = self._phasesets
         return ph
 
     def replace(self, phcache):