diff -r 8122cc5cb543 -r 492c64afc54c mercurial/posix.py
--- a/mercurial/posix.py	Sat Feb 25 17:29:30 2017 +0900
+++ b/mercurial/posix.py	Fri Mar 17 05:10:58 2017 +0530
@@ -408,7 +408,7 @@
         return '"%s"' % s
     global _needsshellquote
     if _needsshellquote is None:
-        _needsshellquote = re.compile(r'[^a-zA-Z0-9._/+-]').search
+        _needsshellquote = re.compile(br'[^a-zA-Z0-9._/+-]').search
     if s and not _needsshellquote(s):
         # "s" shouldn't have to be quoted
         return s