From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sat, 19 Feb 2022 20:15:41 -0800
Subject: [PATCH] Option to have default CustomSpawners in custom worlds

By default, only LevelStem's that specifically match the ResourceKey for
OVERWORLD will have the 5 (currently) impls of CustomSpawner (for
phantoms, wandering traders, etc.). This adds an option to instead of
just looking at the LevelStem key, look at the DimensionType key which
is one level below that. Defaults to off to keep vanilla behavior.

diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 934e948bb112bcfc69e656ac4c6a97f0a72d7b74..a9240274b903f23a5d0b2414b3bc7a984845b6cd 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -589,7 +589,15 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
                 this.commandStorage = new CommandStorage(worldpersistentdata);
             } else {
                 ChunkProgressListener worldloadlistener = this.progressListenerFactory.create(11);
-                world = new ServerLevel(this, this.executor, worldSession, iworlddataserver, worldKey, worlddimension, worldloadlistener, flag, j, ImmutableList.of(), true, this.overworld().getRandomSequences(), org.bukkit.World.Environment.getEnvironment(dimension), gen, biomeProvider);
+                // Paper start - option to use the dimension_type to check if spawners should be added. I imagine mojang will add some datapack-y way of managing this in the future.
+                final List<CustomSpawner> spawners;
+                if (io.papermc.paper.configuration.GlobalConfiguration.get().misc.useDimensionTypeForCustomSpawners && this.registryAccess().registryOrThrow(Registries.DIMENSION_TYPE).getResourceKey(worlddimension.type().value()).orElseThrow() == net.minecraft.world.level.dimension.BuiltinDimensionTypes.OVERWORLD) {
+                    spawners = list;
+                } else {
+                    spawners = Collections.emptyList();
+                }
+                world = new ServerLevel(this, this.executor, worldSession, iworlddataserver, worldKey, worlddimension, worldloadlistener, flag, j, spawners, true, this.overworld().getRandomSequences(), org.bukkit.World.Environment.getEnvironment(dimension), gen, biomeProvider);
+                // Paper end
             }
 
             worlddata.setModdedInfo(this.getServerModName(), this.getModdedStatus().shouldReportAsModified());