diff -r 7126d8b8e0e6 -r a61287a95dc3 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Mon Jan 13 17:14:19 2020 -0500
+++ b/mercurial/localrepo.py	Mon Jan 13 17:15:14 2020 -0500
@@ -8,7 +8,6 @@
 from __future__ import absolute_import
 
 import errno
-import hashlib
 import os
 import random
 import sys
@@ -74,6 +73,7 @@
 )
 
 from .utils import (
+    hashutil,
     procutil,
     stringutil,
 )
@@ -2007,7 +2007,7 @@
             )
 
         idbase = b"%.40f#%f" % (random.random(), time.time())
-        ha = hex(hashlib.sha1(idbase).digest())
+        ha = hex(hashutil.sha1(idbase).digest())
         txnid = b'TXN:' + ha
         self.hook(b'pretxnopen', throw=True, txnname=desc, txnid=txnid)