diff -r 7126d8b8e0e6 -r a61287a95dc3 mercurial/wireprotov1peer.py
--- a/mercurial/wireprotov1peer.py	Mon Jan 13 17:14:19 2020 -0500
+++ b/mercurial/wireprotov1peer.py	Mon Jan 13 17:15:14 2020 -0500
@@ -7,7 +7,6 @@
 
 from __future__ import absolute_import
 
-import hashlib
 import sys
 import weakref
 
@@ -31,6 +30,7 @@
     repository,
     util as interfaceutil,
 )
+from .utils import hashutil
 
 urlreq = util.urlreq
 
@@ -489,7 +489,7 @@
 
         if heads != [b'force'] and self.capable(b'unbundlehash'):
             heads = wireprototypes.encodelist(
-                [b'hashed', hashlib.sha1(b''.join(sorted(heads))).digest()]
+                [b'hashed', hashutil.sha1(b''.join(sorted(heads))).digest()]
             )
         else:
             heads = wireprototypes.encodelist(heads)