--- a/mercurial/templater.py	Sat Mar 03 14:21:47 2018 -0500
+++ b/mercurial/templater.py	Sat Mar 03 12:34:35 2018 -0500
@@ -1600,7 +1600,7 @@
     for style in styles:
         # only plain name is allowed to honor template paths
         if (not style
-            or style in (os.curdir, os.pardir)
+            or style in (os.curdir, pycompat.ospardir)
             or pycompat.ossep in style
             or pycompat.osaltsep and pycompat.osaltsep in style):
             continue