From a24318eedc44af2f5967c4727b7ebf578b8e233a Mon Sep 17 00:00:00 2001
From: ModMaker101 <119018978+ModMaker101@users.noreply.github.com>
Date: Wed, 25 Mar 2026 00:25:18 -0400
Subject: Memory leak fix: Make chunks unload properly (#1406)
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* Fix chunk unload and cleanup logic, fixes #1347

* Applying formatting to code I edited 😝
---
 Minecraft.Client/MultiPlayerChunkCache.cpp | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

(limited to 'Minecraft.Client/MultiPlayerChunkCache.cpp')

diff --git a/Minecraft.Client/MultiPlayerChunkCache.cpp b/Minecraft.Client/MultiPlayerChunkCache.cpp
index 62361ce3..03c47fcc 100644
--- a/Minecraft.Client/MultiPlayerChunkCache.cpp
+++ b/Minecraft.Client/MultiPlayerChunkCache.cpp
@@ -139,19 +139,26 @@ bool MultiPlayerChunkCache::reallyHasChunk(int x, int z)
 	return hasData[idx];
 }
 
-void MultiPlayerChunkCache::drop(int x, int z)
+void MultiPlayerChunkCache::drop(const int x, const int z)
 {
-	// 4J Stu - We do want to drop any entities in the chunks, especially for the case when a player is dead as they will
-	// not get the RemoveEntity packet if an entity is removed.
-	LevelChunk *chunk = getChunk(x, z);
-	if (!chunk->isEmpty())
+	const int ix = x + XZOFFSET;
+	const int iz = z + XZOFFSET;
+	if ((ix < 0) || (ix >= XZSIZE)) return;
+	if ((iz < 0) || (iz >= XZSIZE)) return;
+	const int idx = ix * XZSIZE + iz;
+	LevelChunk* chunk = cache[idx];
+
+	if (chunk != nullptr && !chunk->isEmpty())
 	{
-		// Added parameter here specifies that we don't want to delete tile entities, as they won't get recreated unless they've got update packets
-		// The tile entities are in general only created on the client by virtue of the chunk rebuild
+		// Unload chunk but keep tile entities
 		chunk->unload(false);
 
-		// 4J - We just want to clear out the entities in the chunk, but everything else should be valid
-		chunk->loaded = true;
+		const auto it = std::find(loadedChunkList.begin(), loadedChunkList.end(), chunk);
+		if (it != loadedChunkList.end()) loadedChunkList.erase(it);
+
+		cache[idx] = nullptr;
+		hasData[idx] = false;
+		chunk->loaded = false;
 	}
 }
 
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