--- a/src/topic/revset.py	Wed Jun 10 15:03:39 2015 -0400
+++ b/src/topic/revset.py	Wed Jun 10 16:13:20 2015 -0400
@@ -1,5 +1,7 @@
 from mercurial import revset
 
+from . import constants
+
 def topicset(repo, subset, x):
     """`topic([topic])`
     Specified topic or all changes with any topic specified.
@@ -17,7 +19,8 @@
     else:
         matcher = lambda t: bool(t)
     drafts = subset.filter(lambda r: repo[r].mutable())
-    return drafts.filter(lambda r: matcher(repo[r].extra().get('topic', '')))
+    return drafts.filter(
+        lambda r: matcher(repo[r].extra().get(constants.extrakey, '')))
 
 def modsetup():
     revset.symbols.update({'topic': topicset})