diff -r ac72eee94035 -r 4292bed8da7c mercurial/revlogutils/revlogv0.py
--- a/mercurial/revlogutils/revlogv0.py	Mon May 03 12:21:05 2021 +0200
+++ b/mercurial/revlogutils/revlogv0.py	Mon May 03 12:21:15 2021 +0200
@@ -135,6 +135,8 @@
             nodemap.get(e[4], node.nullrev),
             nodemap.get(e[5], node.nullrev),
             e[6],
+            0,  # no side data support
+            0,  # no side data support
         )
         index.append(e2)
         nodemap[e[6]] = n