--- a/mercurial/unionrepo.py	Mon May 03 21:13:24 2021 +0200
+++ b/mercurial/unionrepo.py	Mon May 03 21:34:02 2021 +0200
@@ -70,6 +70,7 @@
                 _sdo,
                 _sds,
                 _dcm,
+                _sdcm,
             ) = rev
             flags = _start & 0xFFFF
 
@@ -105,6 +106,7 @@
                 0,  # sidedata offset
                 0,  # sidedata size
                 revlog_constants.COMP_MODE_INLINE,
+                revlog_constants.COMP_MODE_INLINE,
             )
             self.index.append(e)
             self.bundlerevs.add(n)