mercurial/templater.py

--- a/mercurial/templater.py	Fri Mar 06 00:14:22 2015 +0900
+++ b/mercurial/templater.py	Fri Mar 13 21:18:59 2015 +0900
@@ -747,7 +747,11 @@
         styles = [styles]
 
     for style in styles:
-        if not style:
+        # only plain name is allowed to honor template paths
+        if (not style
+            or style in (os.curdir, os.pardir)
+            or os.sep in style
+            or os.altsep and os.altsep in style):
             continue
         locations = [os.path.join(style, 'map'), 'map-' + style]
         locations.append('map')