diff -r e0a314bcbc9d -r cac0e0621ceb mercurial/changelog.py
--- a/mercurial/changelog.py	Tue Jun 08 19:55:00 2021 +0200
+++ b/mercurial/changelog.py	Tue Jun 15 12:34:14 2021 +0200
@@ -455,6 +455,7 @@
                     self._realopener, self._indexfile, self._delaybuf
                 )
             self._segmentfile.opener = self.opener
+            self._segmentfile_sidedata.opener = self.opener
         self._delayed = True
         tr.addpending(b'cl-%i' % id(self), self._writepending)
         tr.addfinalize(b'cl-%i' % id(self), self._finalize)
@@ -464,6 +465,7 @@
         self._delayed = False
         self.opener = self._realopener
         self._segmentfile.opener = self.opener
+        self._segmentfile_sidedata.opener = self.opener
         # move redirected index data back into place
         if self._docket is not None:
             self._write_docket(tr)
@@ -504,6 +506,7 @@
             self._divert = True
             self.opener = _divertopener(self._realopener, self._indexfile)
             self._segmentfile.opener = self.opener
+            self._segmentfile_sidedata.opener = self.opener
 
         if self._divert:
             return True