diff -r 05c213cd8ab8 -r e14484e7f562 mercurial/formatter.py
--- a/mercurial/formatter.py	Sat Jun 17 14:53:25 2017 +0530
+++ b/mercurial/formatter.py	Sat Jun 17 15:05:11 2017 +0530
@@ -371,6 +371,7 @@
             props['templ'] = self._t
             props['repo'] = props['ctx'].repo()
             props['revcache'] = {}
+        props = pycompat.strkwargs(props)
         g = self._t(self._tref, ui=self._ui, cache=self._cache, **props)
         self._out.write(templater.stringify(g))