--- a/mercurial/branchmap.py	Sun Mar 10 05:10:00 2024 +0100
+++ b/mercurial/branchmap.py	Sun Mar 10 03:32:50 2024 +0100
@@ -108,7 +108,8 @@
             subsetname = subsettable.get(filtername)
             if subsetname is not None:
                 subset = repo.filtered(subsetname)
-                bcache = self[subset].inherit_for(repo)
+                self.updatecache(subset)
+                bcache = self._per_filter[subset.filtername].inherit_for(repo)
                 extrarevs = subset.changelog.filteredrevs - cl.filteredrevs
                 revs.extend(r for r in extrarevs if r <= bcache.tiprev)
             else: