From 41840220c3a1e3eaa410fcbe7df8580af3477646 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Thu, 15 Aug 2024 11:49:13 -0700
Subject: [PATCH] Optimize version handling in mergeWithChild

---
 ConflictSet.cpp | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index eed9c8a..3756d37 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -1623,7 +1623,7 @@ void mergeWithChild(Node *&self, WriteContext *tls, ConflictSet::Impl *impl,
           getSearchPathPrintable(child).c_str());
 #endif
 
-  InternalVersionT childMaxVersion = maxVersion(child, impl);
+  InternalVersionT childMaxVersion = self3->childMaxVersion[0];
 
   // Construct new partial key for child
   memmove(child->partialKey() + self3->partialKeyLen + 1, child->partialKey(),
@@ -1637,10 +1637,7 @@ void mergeWithChild(Node *&self, WriteContext *tls, ConflictSet::Impl *impl,
 
   // Max versions are stored in the parent, so we need to update it now
   // that we have a new parent.
-  setMaxVersion(child, impl, childMaxVersion);
-  if (child->parent) {
-    rezero(child->parent, tls->zero);
-  }
+  setMaxVersion(child, impl, std::max(childMaxVersion, tls->zero));
 
   getInTree(self, impl) = child;
   tls->release(self3);
@@ -3728,6 +3725,7 @@ InternalVersionT exchangeMaxVersion(Node *n, InternalVersionT newMax) {
 }
 
 void setMaxVersion(Node *n, ConflictSet::Impl *impl, InternalVersionT newMax) {
+  assert(newMax >= InternalVersionT::zero);
   int index = n->parentsIndex;
   n = n->parent;
   if (n == nullptr) {