From 2dcf4acbf2012b8d029ad63310fe0304e8b47f1d 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 387570ed67..fb57cb8394 100644
--- a/src/main/java/net/minecraft/server/SpawnerCreature.java
+++ b/src/main/java/net/minecraft/server/SpawnerCreature.java
@@ -129,9 +129,9 @@ public final class SpawnerCreature {
                             int i2 = blockposition1.getX();
                             int j2 = blockposition1.getY();
                             int k2 = blockposition1.getZ();
-                            IBlockData iblockdata = worldserver.getType(blockposition1);
+                            IBlockData iblockdata = worldserver.getTypeIfLoadedAndInBounds(blockposition1);  // Paper - don't load chunks for mob spawn
 
-                            if (!iblockdata.isOccluding()) {
+                            if (iblockdata != null && !iblockdata.isOccluding()) { // Paper - don't load chunks for mob spawn
                                 int l2 = 0;
                                 int i3 = 0;
 
@@ -167,7 +167,7 @@ public final class SpawnerCreature {
                                                         i4 = biomebase_biomemeta.c + worldserver.random.nextInt(1 + biomebase_biomemeta.d - biomebase_biomemeta.c);
                                                     }
 
-                                                    if (worldserver.a(enumcreaturetype, biomebase_biomemeta, (BlockPosition) blockposition_mutableblockposition)) {
+                                                    if (worldserver.isLoadedAndInBounds(blockposition_mutableblockposition) && worldserver.a(enumcreaturetype, biomebase_biomemeta, (BlockPosition) blockposition_mutableblockposition)) { // Paper - don't load chunks for mob spawn
                                                         EntityPositionTypes.Surface entitypositiontypes_surface = EntityPositionTypes.a(biomebase_biomemeta.b);
                                                         if (entitypositiontypes_surface != null && a(entitypositiontypes_surface, worldserver, blockposition_mutableblockposition, biomebase_biomemeta.b)) {
                                                             EntityInsentient entityinsentient;
-- 
2.19.0