--- a/mercurial/manifest.py	Mon Aug 05 10:10:03 2024 +0200
+++ b/mercurial/manifest.py	Mon Aug 05 10:11:51 2024 +0200
@@ -838,7 +838,7 @@
                 selfdirs[d] = readsubtree(subpath(d), node).copy()
             else:
                 selfdirs[d] = readsubtree(subpath(d), node)
-        self._lazydirs = {}
+        self._lazydirs.clear()
 
     def _loadlazy(self, d):
         v = self._lazydirs.get(d)