diff --git a/mercurial/phases.py b/mercurial/phases.py
--- a/mercurial/phases.py
+++ b/mercurial/phases.py
@@ -172,7 +172,7 @@ class phasecache(object):
 
     def replace(self, phcache):
         """replace all values in 'self' with content of phcache"""
-        for a in 'phaseroots dirty opener _phaserevs _phasesets'.split():
+        for a in ('phaseroots', 'dirty', 'opener', '_phaserevs', '_phasesets'):
             setattr(self, a, getattr(phcache, a))
 
     def _getphaserevsnative(self, repo):