diff -r a41565bef69f -r e8c11a2c96c0 mercurial/revlog.py
--- a/mercurial/revlog.py	Thu Feb 18 17:36:52 2021 +0100
+++ b/mercurial/revlog.py	Thu Feb 18 18:18:35 2021 +0100
@@ -204,6 +204,7 @@
     baserevisionsize = attr.ib()
     revision = attr.ib()
     delta = attr.ib()
+    sidedata = attr.ib()
     linknode = attr.ib(default=None)
 
 
@@ -2587,6 +2588,7 @@
                     dfh,
                     alwayscache=alwayscache,
                     deltacomputer=deltacomputer,
+                    sidedata=sidedata,
                 )
 
                 if addrevisioncb: