From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 12 Sep 2018 21:12:57 -0400
Subject: [PATCH] Prevent mob spawning from loading/generating chunks

also prevents if out of world border bounds

diff --git a/src/main/java/net/minecraft/server/SpawnerCreature.java b/src/main/java/net/minecraft/server/SpawnerCreature.java
index 4b1a5e92cc05df06edd6d2d7eab5ca70b70ede79..32d45b54fc4e67555a7f016ac72787a8ad4818f3 100644
--- a/src/main/java/net/minecraft/server/SpawnerCreature.java
+++ b/src/main/java/net/minecraft/server/SpawnerCreature.java
@@ -139,9 +139,9 @@ public final class SpawnerCreature {
         StructureManager structuremanager = worldserver.getStructureManager();
         ChunkGenerator chunkgenerator = worldserver.getChunkProvider().getChunkGenerator();
         int i = blockposition.getY();
-        IBlockData iblockdata = ichunkaccess.getType(blockposition);
+        IBlockData iblockdata = worldserver.getTypeIfLoadedAndInBounds(blockposition); // Paper - don't load chunks for mob spawn
 
-        if (!iblockdata.isOccluding(ichunkaccess, blockposition)) {
+        if (iblockdata != null && !iblockdata.isOccluding(ichunkaccess, blockposition)) { // Paper - don't load chunks for mob spawn
             BlockPosition.MutableBlockPosition blockposition_mutableblockposition = new BlockPosition.MutableBlockPosition();
             int j = 0;
             int k = 0;
@@ -170,7 +170,7 @@ public final class SpawnerCreature {
                             if (entityhuman != null) {
                                 double d2 = entityhuman.g(d0, (double) i, d1);
 
-                                if (a(worldserver, ichunkaccess, blockposition_mutableblockposition, d2)) {
+                                if (a(worldserver, ichunkaccess, blockposition_mutableblockposition, d2) && worldserver.isLoadedAndInBounds(blockposition_mutableblockposition)) { // Paper - don't load chunks for mob spawn
                                     if (biomebase_biomemeta == null) {
                                         biomebase_biomemeta = a(worldserver, structuremanager, chunkgenerator, enumcreaturetype, worldserver.random, (BlockPosition) blockposition_mutableblockposition);
                                         if (biomebase_biomemeta == null) {