diff -r c84a07530040 -r 14b184263846 mercurial/patch.py
--- a/mercurial/patch.py	Thu Dec 17 14:38:22 2015 +0000
+++ b/mercurial/patch.py	Thu Dec 17 20:13:29 2015 +0000
@@ -1491,7 +1491,6 @@
                 self.toline += len(self.before) + h.added
                 self.before = []
                 self.hunk = []
-                self.proc = ''
             self.context = context
 
         def addhunk(self, hunk):