--- a/mercurial/revlogutils/nodemap.py	Tue Mar 02 00:05:22 2021 +0100
+++ b/mercurial/revlogutils/nodemap.py	Thu Mar 18 18:24:59 2021 -0400
@@ -570,7 +570,7 @@
 def parse_data(data):
     """parse parse nodemap data into a nodemap Trie"""
     if (len(data) % S_BLOCK.size) != 0:
-        msg = "nodemap data size is not a multiple of block size (%d): %d"
+        msg = b"nodemap data size is not a multiple of block size (%d): %d"
         raise error.Abort(msg % (S_BLOCK.size, len(data)))
     if not data:
         return Block(), None