--- a/mercurial/patch.py	Sat Apr 07 21:21:03 2018 +0900
+++ b/mercurial/patch.py	Sat Apr 07 21:23:42 2018 +0900
@@ -2133,7 +2133,7 @@
     code = fp.close()
     if code:
         raise PatchError(_("patch command failed: %s") %
-                         procutil.explainexit(code)[0])
+                         procutil.explainexit(code))
     return fuzz
 
 def patchbackend(ui, backend, patchobj, strip, prefix, files=None,