From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Wed, 6 Jan 2021 00:34:04 -0800
Subject: [PATCH] Add methods to get world by key


diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index f904ce285548a81835b1d3af9c05f00f84d5d3da..6f30668471c2076e2bbd8af79791bbe362f4d08e 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -1138,9 +1138,15 @@ public final class CraftServer implements Server {
         File folder = new File(this.getWorldContainer(), name);
         World world = this.getWorld(name);
 
-        if (world != null) {
-            return world;
+        // Paper start
+        World worldByKey = this.getWorld(creator.key());
+        if (world != null || worldByKey != null) {
+            if (world == worldByKey) {
+                return world;
+            }
+            throw new IllegalArgumentException("Cannot create a world with key " + creator.key() + " and name " + name + " one (or both) already match a world that exists");
         }
+        // Paper end
 
         if ((folder.exists()) && (!folder.isDirectory())) {
             throw new IllegalArgumentException("File exists with the name '" + name + "' and isn't a folder");
@@ -1232,7 +1238,7 @@ public final class CraftServer implements Server {
         } else if (name.equals(levelName + "_the_end")) {
             worldKey = net.minecraft.world.level.Level.END;
         } else {
-            worldKey = ResourceKey.create(Registry.DIMENSION_REGISTRY, new ResourceLocation(name.toLowerCase(java.util.Locale.ENGLISH)));
+            worldKey = ResourceKey.create(Registry.DIMENSION_REGISTRY, new net.minecraft.resources.ResourceLocation(creator.key().getNamespace().toLowerCase(java.util.Locale.ENGLISH), creator.key().getKey().toLowerCase(java.util.Locale.ENGLISH))); // Paper
         }
 
         ServerLevel internal = (ServerLevel) new ServerLevel(this.console, console.executor, worldSession, worlddata, worldKey, holder, this.getServer().progressListenerFactory.create(11),
@@ -1324,6 +1330,15 @@ public final class CraftServer implements Server {
         return null;
     }
 
+    // Paper start
+    @Override
+    public World getWorld(NamespacedKey worldKey) {
+        ServerLevel worldServer = console.getLevel(ResourceKey.create(Registry.DIMENSION_REGISTRY, CraftNamespacedKey.toMinecraft(worldKey)));
+        if (worldServer == null) return null;
+        return worldServer.getWorld();
+    }
+    // Paper end
+
     public void addWorld(World world) {
         // Check if a World already exists with the UID.
         if (this.getWorld(world.getUID()) != null) {