--- a/mercurial/templater.py	Fri Jan 17 00:16:48 2014 -0800
+++ b/mercurial/templater.py	Wed Feb 05 20:22:28 2014 -0800
@@ -368,7 +368,14 @@
     cl = mapping['ctx']._repo.changelog
     def isvalid(test):
         try:
-            cl.index.partialmatch(test)
+            try:
+                cl.index.partialmatch(test)
+            except AttributeError:
+                # Pure mercurial doesn't support partialmatch on the index.
+                # Fallback to the slow way.
+                if cl._partialmatch(test) is None:
+                    return False
+
             try:
                 int(test)
                 return False