diff -r 2d84947cd85d -r 4462a981e8df mercurial/patch.py
--- a/mercurial/patch.py	Tue May 02 17:05:22 2017 +0900
+++ b/mercurial/patch.py	Wed Apr 26 21:56:47 2017 +0900
@@ -26,7 +26,6 @@
     short,
 )
 from . import (
-    base85,
     copies,
     diffhelpers,
     encoding,
@@ -1430,7 +1429,7 @@
             else:
                 l = ord(l) - ord('a') + 27
             try:
-                dec.append(base85.b85decode(line[1:])[:l])
+                dec.append(util.b85decode(line[1:])[:l])
             except ValueError as e:
                 raise PatchError(_('could not decode "%s" binary patch: %s')
                                  % (self._fname, str(e)))