diff -r 861fe9273d57 -r 59c6f99723b1 mercurial/revlogutils/rewrite.py
--- a/mercurial/revlogutils/rewrite.py	Tue Oct 10 10:58:28 2023 +0200
+++ b/mercurial/revlogutils/rewrite.py	Tue Oct 10 11:02:00 2023 +0200
@@ -539,7 +539,7 @@
             util.copyfile(
                 rl.opener.join(index_file),
                 rl.opener.join(new_file_path),
-                checkambig=rl._checkambig,
+                checkambig=rl.data_config.check_ambig,
             )
 
             with rl.opener(new_file_path, mode=b"r+") as fp: