--- a/mercurial/commands.py	Tue Mar 14 18:16:13 2017 +0900
+++ b/mercurial/commands.py	Tue Mar 14 18:23:59 2017 +0900
@@ -3393,6 +3393,7 @@
     Returns 0 on success.
 
     """
+    opts = pycompat.byteskwargs(opts)
     if opts.get('follow') and opts.get('rev'):
         opts['rev'] = [revsetlang.formatspec('reverse(::%lr)', opts.get('rev'))]
         del opts['follow']