From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Fri, 8 May 2020 20:30:58 -0400
Subject: [PATCH] Fix CraftServer.unloadWorld Leak

The dimension manager was still registered which leaked the entire World

diff --git a/src/main/java/net/minecraft/server/DimensionManager.java b/src/main/java/net/minecraft/server/DimensionManager.java
index 393bc4dc700bbf8653db0662c7957f676b0a647a..410ab224fbb05bfbf4aa847d69b150bfe75d32f6 100644
--- a/src/main/java/net/minecraft/server/DimensionManager.java
+++ b/src/main/java/net/minecraft/server/DimensionManager.java
@@ -20,6 +20,15 @@ public class DimensionManager implements MinecraftSerializable {
     private final boolean hasSkyLight;
     private final GenLayerZoomer genLayerZoomer;
 
+    // Paper start
+    public static void unregister(String s, DimensionManager dimensionmanager) {
+        if (dimensionmanager == OVERWORLD || dimensionmanager == NETHER || dimensionmanager == THE_END) { return; } // do not unregister the default worlds
+        MCUtil.MAIN_EXECUTOR.execute(() -> {
+            RegistryMaterials<DimensionManager> registry = (RegistryMaterials<DimensionManager>) IRegistry.DIMENSION_TYPE;
+            registry.deleteValue(new MinecraftKey(s), dimensionmanager);
+        });
+    }
+    // Paper end
     public static DimensionManager register(String s, DimensionManager dimensionmanager) {
         return (DimensionManager) IRegistry.a(IRegistry.DIMENSION_TYPE, dimensionmanager.id, s, dimensionmanager);
     }
diff --git a/src/main/java/net/minecraft/server/RegistryID.java b/src/main/java/net/minecraft/server/RegistryID.java
index e8a48b9a4c999281869dfb85577c2b44d6e30eb7..5335e7acc85f0fe9699e5ed59e5aaae5f381347d 100644
--- a/src/main/java/net/minecraft/server/RegistryID.java
+++ b/src/main/java/net/minecraft/server/RegistryID.java
@@ -9,12 +9,26 @@ import javax.annotation.Nullable;
 public class RegistryID<K> implements Registry<K> {
 
     private static final Object a = null;
-    private K[] b;
+    private K[] b; // Paper - diff below
     private int[] c;
-    private K[] d;
+    private K[] d; // Paper - diff below
     private int e;
     private int f;
     private java.util.BitSet usedIds; // Paper
+    // Paper start
+    public void removeValue(K value) {
+        removeValue(value, this.b);
+        removeValue(value, this.d);
+        rehash(this.b.length);
+    }
+    public void removeValue(K value, K[] arr) {
+        for (int i = 0; i < arr.length; i++) {
+            K k = arr[i];
+            if (k == value) {
+                arr[i] = null;
+            }
+        }
+    }
 
     public RegistryID(int i) {
         i = (int) ((float) i / 0.8F);
@@ -58,6 +72,7 @@ public class RegistryID<K> implements Registry<K> {
         return this.e;
     }
 
+    private void rehash(int i) { d(i); } // Paper - OBFHELPER
     private void d(int i) {
         K[] ak = this.b;
         int[] aint = this.c;
diff --git a/src/main/java/net/minecraft/server/RegistryMaterials.java b/src/main/java/net/minecraft/server/RegistryMaterials.java
index 8477febca23b575da21023b4d7c18bb679cf3b30..dcdd8d38dee89ae7ac404a431e51a61c50b6d45c 100644
--- a/src/main/java/net/minecraft/server/RegistryMaterials.java
+++ b/src/main/java/net/minecraft/server/RegistryMaterials.java
@@ -22,18 +22,23 @@ public class RegistryMaterials<T> extends IRegistryWritable<T> {
     private int V;
 
     public RegistryMaterials() {}
+    public T deleteValue(MinecraftKey minecraftkey, T value) {
+        this.b.removeValue(value); // Diff 1
+        this.d = null; // Diff 2
+        return this.c.remove(minecraftkey); // Diff 3
+    }
 
     @Override
     public <V extends T> V a(int i, MinecraftKey minecraftkey, V v0) {
-        this.b.a(v0, i);
+        this.b.a(v0, i); // Paper - diff above 1
         Validate.notNull(minecraftkey);
         Validate.notNull(v0);
-        this.d = null;
+        this.d = null; // Diff 2
         if (this.c.containsKey(minecraftkey)) {
             RegistryMaterials.LOGGER.debug("Adding duplicate key '{}' to registry", minecraftkey);
         }
 
-        this.c.put(minecraftkey, v0);
+        this.c.put(minecraftkey, v0); // Paper - diff3
         if (this.V <= i) {
             this.V = i + 1;
         }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index b89f99a66fe2ab9ad4c956c38c9e4b1d79716c9c..c2b7cb36052455eef2100a1924dc76a5921fa858 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -60,6 +60,7 @@ import net.minecraft.server.EntityPlayer;
 import net.minecraft.server.EnumDifficulty;
 import net.minecraft.server.EnumGamemode;
 import net.minecraft.server.IRecipe;
+import net.minecraft.server.IRegistry;
 import net.minecraft.server.Item;
 import net.minecraft.server.ItemWorldMap;
 import net.minecraft.server.Items;
@@ -1099,7 +1100,11 @@ public final class CraftServer implements Server {
         }
 
         worlds.remove(world.getName().toLowerCase(java.util.Locale.ENGLISH));
-        console.worldServer.remove(handle.getWorldProvider().getDimensionManager());
+        // Paper start
+        DimensionManager dimensionManager = handle.getWorldProvider().getDimensionManager();
+        DimensionManager.unregister(world.getName().toLowerCase(java.util.Locale.ENGLISH), dimensionManager);
+        console.worldServer.remove(dimensionManager);
+        // Paper end
         return true;
     }