--- a/hgext/fastannotate/context.py	Sun Nov 18 02:40:47 2018 +0100
+++ b/hgext/fastannotate/context.py	Mon Nov 19 21:12:13 2018 +0300
@@ -138,7 +138,7 @@
         (k, getattr(diffopts, k))
         for k in mdiff.diffopts.defaults
     ))
-    return hashlib.sha1(diffoptstr).hexdigest()[:6]
+    return node.hex(hashlib.sha1(diffoptstr).digest())[:6]
 
 _defaultdiffopthash = hashdiffopts(mdiff.defaultopts)