diff -r fa9747e7fc86 -r a981ab2a1b4c mercurial/patch.py
--- a/mercurial/patch.py	Fri Jan 12 22:18:42 2018 +0900
+++ b/mercurial/patch.py	Sat Dec 30 00:13:56 2017 +0530
@@ -12,6 +12,7 @@
 import copy
 import difflib
 import email
+import email.parser as emailparser
 import errno
 import hashlib
 import os
@@ -108,7 +109,7 @@
             cur.append(line)
         c = chunk(cur)
 
-        m = email.Parser.Parser().parse(c)
+        m = emailparser.Parser().parse(c)
         if not m.is_multipart():
             yield msgfp(m)
         else:
@@ -217,7 +218,7 @@
     fd, tmpname = tempfile.mkstemp(prefix='hg-patch-')
     tmpfp = os.fdopen(fd, pycompat.sysstr('w'))
     try:
-        msg = email.Parser.Parser().parse(fileobj)
+        msg = emailparser.Parser().parse(fileobj)
 
         subject = msg['Subject'] and mail.headdecode(msg['Subject'])
         data['user'] = msg['From'] and mail.headdecode(msg['From'])