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/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 153f07bac06093b43a1f5b0f8e1a46ffbe6407e5..a7ebf6d9f79ce50a90c3c903563e00a10607f9f2 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -679,4 +679,9 @@ public class PaperConfig {
         }
         globalMaxConcurrentChunkLoads = getDouble("settings.chunk-loading.global-max-concurrent-loads", 500.0);
     }
+
+    public static boolean useDimensionTypeForCustomSpawners;
+    private static void useDimensionTypeForCustomSpawners() {
+        useDimensionTypeForCustomSpawners = getBoolean("settings.use-dimension-type-for-custom-spawners", false);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 1674deebbeab0995ed7acacf8052e1daf4d2a7bc..8014b8a20dfc1f348510eaad6ff42200c9ba4baa 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -689,7 +689,15 @@ 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, dimensionmanager, worldloadlistener, chunkgenerator, flag, j, ImmutableList.of(), true, 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 (com.destroystokyo.paper.PaperConfig.useDimensionTypeForCustomSpawners && this.registryHolder.registryOrThrow(Registry.DIMENSION_TYPE_REGISTRY).getResourceKey(dimensionmanager).orElseThrow() == DimensionType.OVERWORLD_LOCATION) {
+                    spawners = list;
+                } else {
+                    spawners = Collections.emptyList();
+                }
+                world = new ServerLevel(this, this.executor, worldSession, iworlddataserver, worldKey, dimensionmanager, worldloadlistener, chunkgenerator, flag, j, spawners, true, org.bukkit.World.Environment.getEnvironment(dimension), gen, biomeProvider);
+                // Paper end
             }
 
             worlddata.setModdedInfo(this.getServerModName(), this.getModdedStatus().shouldReportAsModified());