From 25ce57966db2f0d986068b1a966c4d804de9dfaf 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 6d1b98b..4a2cad6 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -309,6 +309,7 @@ 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 9335cef..6517e5a 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