--- a/mercurial/patch.py	Fri Dec 29 05:22:06 2017 +0530
+++ b/mercurial/patch.py	Fri Dec 29 05:25:27 2017 +0530
@@ -2654,7 +2654,7 @@
         l = len(text)
         s = hashlib.sha1('blob %d\0' % l)
         s.update(text)
-        return s.hexdigest()
+        return hex(s.digest())
 
     if opts.noprefix:
         aprefix = bprefix = ''