diff -r 6ccb07b9eeeb -r 83ce99f5e7f2 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Tue Oct 10 10:02:53 2023 +0200
+++ b/mercurial/localrepo.py	Tue Oct 10 10:03:01 2023 +0200
@@ -1107,10 +1107,10 @@
         lazydeltabase = ui.configbool(
             b'storage', b'revlog.reuse-external-delta-parent'
         )
-    if lazydeltabase is None:
-        lazydeltabase = not scmutil.gddeltaconfig(ui)
-    options[b'lazydelta'] = lazydelta
-    options[b'lazydeltabase'] = lazydeltabase
+        if lazydeltabase is None:
+            lazydeltabase = not scmutil.gddeltaconfig(ui)
+    delta_config.lazy_delta = lazydelta
+    delta_config.lazy_delta_base = lazydeltabase
 
     chainspan = ui.configbytes(b'experimental', b'maxdeltachainspan')
     if 0 <= chainspan: