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/ServerChunkCache.cpp | 57 ++++++++++++-----------------------
 1 file changed, 19 insertions(+), 38 deletions(-)

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

diff --git a/Minecraft.Client/ServerChunkCache.cpp b/Minecraft.Client/ServerChunkCache.cpp
index c7d70c7d..54312ffa 100644
--- a/Minecraft.Client/ServerChunkCache.cpp
+++ b/Minecraft.Client/ServerChunkCache.cpp
@@ -80,54 +80,31 @@ vector<LevelChunk *> *ServerChunkCache::getLoadedChunkList()
 	return &m_loadedChunkList;
 }
 
-void ServerChunkCache::drop(int x, int z)
+void ServerChunkCache::drop(const int x, const int z)
 {
-	// 4J - we're not dropping things anymore now that we have a fixed sized cache
-#ifdef _LARGE_WORLDS
-
-	bool canDrop = false;
-//	if (level->dimension->mayRespawn())
-//	{
-//		Pos *spawnPos = level->getSharedSpawnPos();
-//		int xd = x * 16 + 8 - spawnPos->x;
-//		int zd = z * 16 + 8 - spawnPos->z;
-//		delete spawnPos;
-//		int r = 128;
-//		if (xd < -r || xd > r || zd < -r || zd > r)
-//		{
-//			canDrop = true;
-//}
-//	}
-//	else
-	{
-		canDrop = true;
-	}
-	if(canDrop)
+	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)
 	{
-		int ix = x + XZOFFSET;
-		int iz = z + XZOFFSET;
-		// Check we're in range of the stored level
-		if( ( ix < 0 ) || ( ix >= XZSIZE ) ) return;
-		if( ( iz < 0 ) || ( iz >= XZSIZE ) ) return;
-		int idx = ix * XZSIZE + iz;
-		LevelChunk *chunk = cache[idx];
-
-		if(chunk)
-		{
-			m_toDrop.push_back(chunk);
-		}
+		const auto it = std::find(m_loadedChunkList.begin(), m_loadedChunkList.end(), chunk);
+		if (it != m_loadedChunkList.end()) m_loadedChunkList.erase(it);
+
+		cache[idx] = nullptr;
+		chunk->loaded = false;
 	}
-#endif
 }
 
 void ServerChunkCache::dropAll()
 {
-#ifdef _LARGE_WORLDS
 	for (LevelChunk *chunk : m_loadedChunkList)
 	{
 		drop(chunk->x, chunk->z);
-}
-#endif
+	}
 }
 
 // 4J - this is the original (and virtual) interface to create
@@ -957,6 +934,10 @@ bool ServerChunkCache::tick()
 						m_unloadedCache[idx] = chunk;
 						cache[idx] = nullptr;
 					}
+					else
+					{
+						continue;
+					}
 				}
 				m_toDrop.pop_front();
 			}
-- 
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