diff -r ab7b4fba8bde -r abc327f9628b mercurial/revlogutils/debug.py
--- a/mercurial/revlogutils/debug.py	Mon Jan 06 01:06:59 2025 -0500
+++ b/mercurial/revlogutils/debug.py	Mon Jan 06 01:12:54 2025 -0500
@@ -305,9 +305,9 @@
     # intermediate snapshot against a prior snapshot
     numsemi = 0
     # snapshot count per depth
-    numsnapdepth = collections.defaultdict(lambda: 0)
+    numsnapdepth = collections.defaultdict(int)
     # number of snapshots with a non-ancestor delta
-    numsnapdepth_nad = collections.defaultdict(lambda: 0)
+    numsnapdepth_nad = collections.defaultdict(int)
     # delta against previous revision
     numprev = 0
     # delta against prev, where prev is a non-ancestor