From 6d9810fe7f9deaf9cd83f053d029924379124a32 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Mon, 3 Aug 2026 17:38:21 -0400
Subject: [PATCH] Poison Node48 reverseIndex slot on erase

When a Node48 loses a child, the vacated reverseIndex slot would otherwise
remain defined, letting valgrind miss reads that rely on the stale value.
Mark it undefined, mirroring the existing poisoning of the vacated children
slot.
---
 ConflictSet.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index a82d0d1..5572dd3 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -2025,6 +2025,8 @@ Node *erase(Node *self, WriteContext *writeContext, bool logical) {
     parent48->childMaxVersion[lastChildrenIndex] = writeContext->zero;
     VALGRIND_MAKE_MEM_UNDEFINED(parent48->children + lastChildrenIndex,
                                 sizeof(parent48->children[0]));
+    VALGRIND_MAKE_MEM_UNDEFINED(parent48->reverseIndex + lastChildrenIndex,
+                                sizeof(parent48->reverseIndex[0]));
 
     if (needsDownsize(parent48)) {
       downsize(parent48, writeContext);