From c899237b9f819e1f2c85ee79cbc06548f049c69b Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 12 May 2016 02:03:56 -0400
Subject: [PATCH] Fix Chunk Unload Queue Issues

Vanilla implemented similar logic as Paper had pre 1.9.4, but Spigot
has not resolved all the bugs with the changes.

This patch fixes known issues and really should be applied by Spigot team.

diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index bb8fe9c..774077e 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -47,7 +47,7 @@ public class Chunk {
     private long w;
     private int x;
     private ConcurrentLinkedQueue<BlockPosition> y;
-    public boolean d;
+    public boolean d;public void setShouldUnload(boolean unload) { this.d = unload; } public boolean isUnloading() { return d; } // Paper // OBFHELPER
     protected gnu.trove.map.hash.TObjectIntHashMap<Class> entityCount = new gnu.trove.map.hash.TObjectIntHashMap<Class>(); // Spigot
 
     // Paper start
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index 8f29358..33b3db7 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -318,6 +318,7 @@ public class ChunkProviderServer implements IChunkProvider {
                     Chunk chunk = (Chunk) this.chunks.get(olong);
 
                     if (chunk != null && chunk.d) {
+                        chunk.setShouldUnload(false); // Paper
                         // CraftBukkit start
                         ChunkUnloadEvent event = new ChunkUnloadEvent(chunk.bukkitChunk);
                         this.world.getServer().getPluginManager().callEvent(event);
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 4459e33..22d142a 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -303,6 +303,9 @@ public class CraftWorld implements World {
             // Use the default variant of loadChunk when generate == true.
             return world.getChunkProviderServer().getChunkAt(x, z) != null;
         }
+        // Paper start - below is not updated for the new unload queue logic.
+        return world.getChunkProviderServer().getOrLoadChunkAt(x, z) != null;
+        /*
 
         world.getChunkProviderServer().unloadQueue.remove(ChunkCoordIntPair.a(x, z));
         net.minecraft.server.Chunk chunk = world.getChunkProviderServer().chunks.get(ChunkCoordIntPair.a(x, z));
@@ -312,7 +315,7 @@ public class CraftWorld implements World {
             chunk = world.getChunkProviderServer().getOrLoadChunkAt(x, z);
             world.timings.syncChunkLoadTimer.stopTiming(); // Spigot
         }
-        return chunk != null;
+        return chunk != null;*/ // Paper end
     }
 
     private void chunkLoadPostProcess(net.minecraft.server.Chunk chunk, int cx, int cz) {
@@ -1550,7 +1553,7 @@ public class CraftWorld implements World {
             }
 
             // Already unloading?
-            if (cps.unloadQueue.contains(ChunkCoordIntPair.a(chunk.locX, chunk.locZ))) {
+            if (chunk.isUnloading()) { // Paper
                 continue;
             }
 
-- 
2.8.3