From 9aa06f349c50a1ec8a070797607d8a01645b5a9d Mon Sep 17 00:00:00 2001
From: Aaron Kimbrell <aronwk.aaron@gmail.com>
Date: Fri, 2 Oct 2026 08:19:18 -0500
Subject: [PATCH] fix(entity): message handlers run in the order they
 registered, as the client

Handlers sat in an unordered_multimap, whose order for one message is up to
the standard library: GCC ran them newest first, so the components loaded
last answered a RequestUse first, and Windows builds could differ. They are
now kept per message in registration order: the object's own handlers, then
its components' in load order (LWOGameObject::PassMessageToComponents).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 dGame/Entity.cpp | 13 +++++++++----
 dGame/Entity.h   |  4 +++-
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/dGame/Entity.cpp b/dGame/Entity.cpp
index b689de8bf..95175d9f4 100644
--- a/dGame/Entity.cpp
+++ b/dGame/Entity.cpp
@@ -1731,18 +1731,23 @@ int32_t Entity::GetCollisionGroup() const {
 	return 0;
 }
 
+// LWOGameObject::PassMessageToComponents (0x00f62500): every handler registered for the message, in registration
+// order; only the ones there when the call starts (the client copies the list first; GetPosition is too hot for a copy)
 bool Entity::HandleMsg(GameMessages::GameMsg& msg) const {
+	const auto it = m_MsgHandlers.find(msg.msgId);
+	if (it == m_MsgHandlers.end()) return false;
+
 	bool handled = false;
-	auto [beg, end] = m_MsgHandlers.equal_range(msg.msgId);
-	for (auto& it = beg; it != end; ++it) {
-		if (it->second) handled |= it->second(msg);
+	const auto& handlers = it->second;
+	for (size_t i = 0, count = handlers.size(); i < count; i++) {
+		if (handlers[i]) handled |= handlers[i](msg);
 	}
 
 	return handled;
 }
 
 void Entity::RegisterMsg(const MessageType::Game msgId, std::function<bool(GameMessages::GameMsg&)> handler) {
-	m_MsgHandlers.emplace(msgId, handler);
+	m_MsgHandlers[msgId].push_back(std::move(handler));
 }
 
 bool Entity::MsgRequestServerObjectInfo(GameMessages::RequestServerObjectInfoEvent& event) {
diff --git a/dGame/Entity.h b/dGame/Entity.h
index 5906d6448..8a2b93c5b 100644
--- a/dGame/Entity.h
+++ b/dGame/Entity.h
@@ -480,7 +480,9 @@ private:
 	// objectID of receiver and map of notification name to script
 	std::map<LWOOBJID, std::map<std::string, CppScripts::Script*>> m_Subscriptions;
 
-	std::unordered_multimap<MessageType::Game, std::function<bool(GameMessages::GameMsg&)>> m_MsgHandlers;
+	// Each message's handlers in the order they registered: the object's own, then its components' in load order
+	// (LWOGameObject::registeredGameMessages)
+	std::unordered_map<MessageType::Game, std::vector<std::function<bool(GameMessages::GameMsg&)>>> m_MsgHandlers;
 };
 
 /**