--- a/mercurial/templater.py	Sat Oct 14 01:20:12 2017 -0400
+++ b/mercurial/templater.py	Thu Oct 05 14:15:05 2017 -0400
@@ -427,9 +427,9 @@
         sym = findsymbolicname(arg)
         if sym:
             msg = (_("template filter '%s' is not compatible with keyword '%s'")
-                   % (filt.func_name, sym))
+                   % (filt.__name__, sym))
         else:
-            msg = _("incompatible use of template filter '%s'") % filt.func_name
+            msg = _("incompatible use of template filter '%s'") % filt.__name__
         raise error.Abort(msg)
 
 def buildmap(exp, context):