diff -r b433233e25d9 -r dbba18ba26d4 mercurial/templater.py
--- a/mercurial/templater.py	Fri Mar 11 21:55:44 2016 +0900
+++ b/mercurial/templater.py	Wed Mar 09 23:59:26 2016 +0900
@@ -547,12 +547,8 @@
         # i18n: "label" is a keyword
         raise error.ParseError(_("label expects two arguments"))
 
+    ui = mapping['ui']
     thing = evalstring(context, mapping, args[1])
-
-    ui = mapping.get('ui', '')
-    if isinstance(ui, str):
-        return thing
-
     # preserve unknown symbol as literal so effects like 'red', 'bold',
     # etc. don't need to be quoted
     label = evalstringliteral(context, mapping, args[0])