diff -r 4cd214c9948d -r a41565bef69f mercurial/revlog.py
--- a/mercurial/revlog.py	Fri Feb 19 11:07:10 2021 +0100
+++ b/mercurial/revlog.py	Thu Feb 18 17:36:52 2021 +0100
@@ -2527,7 +2527,7 @@
             deltacomputer = deltautil.deltacomputer(self)
             # loop through our set of deltas
             for data in deltas:
-                node, p1, p2, linknode, deltabase, delta, flags = data
+                node, p1, p2, linknode, deltabase, delta, flags, sidedata = data
                 link = linkmapper(linknode)
                 flags = flags or REVIDX_DEFAULT_FLAGS