Paper/patches/server/0766-Use-correct-LevelStem-registry-when-loading-default-.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Sat, 16 Oct 2021 17:38:35 -0700
Subject: [PATCH] Use correct LevelStem registry when loading default
 end/nether


diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index c245c1f4611f7273c8da629f774e0c64e9f98fc2..481a5dbad82f3f8dd5b1bf8ab207d82ec73d5bbd 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -635,7 +635,14 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
             long i = generatorsettings.seed();
             long j = BiomeManager.obfuscateSeed(i);
             List<CustomSpawner> list = ImmutableList.of(new PhantomSpawner(), new PatrolSpawner(), new CatSpawner(), new VillageSiege(), new WanderingTraderSpawner(iworlddataserver));
-            LevelStem worlddimension = (LevelStem) registrymaterials.get(dimensionKey);
+            // Paper start - Use correct LevelStem registry
+            final LevelStem worlddimension;
+            if (dimensionKey == LevelStem.END || dimensionKey == LevelStem.NETHER) {
+                worlddimension = generatorsettings.dimensions().get(dimensionKey);
+            } else {
+                worlddimension = registrymaterials.get(dimensionKey);
+            }
+            // Paper end
             DimensionType dimensionmanager;
             ChunkGenerator chunkgenerator;