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 224443e03c9e55af2744eebd7e754e2a1b3fa296..fdac5bb3a2d4a73035e1d914979b87fc224b6b20 100644
--- a/src/main/java/net/minecraft/server/SpawnerCreature.java
+++ b/src/main/java/net/minecraft/server/SpawnerCreature.java
@@ -25,9 +25,9 @@ public final class SpawnerCreature {
         int l = blockposition1.getZ();
 
         if (k >= 1) {
-            IBlockData iblockdata = chunk.getType(blockposition1);
+            IBlockData iblockdata = worldserver.getTypeIfLoadedAndInBounds(blockposition1);  // Paper - don't load chunks for mob spawn
 
-            if (!iblockdata.isOccluding(chunk, blockposition1)) {
+            if (iblockdata != null && !iblockdata.isOccluding(chunk, blockposition1)) { // Paper - don't load chunks for mob spawn
                 BlockPosition.MutableBlockPosition blockposition_mutableblockposition = new BlockPosition.MutableBlockPosition();
                 int i1 = 0;
 
@@ -55,7 +55,7 @@ public final class SpawnerCreature {
                                 if (entityhuman != null) {
                                     double d0 = entityhuman.g((double) f, (double) k, (double) f1);
 
-                                    if (d0 > 576.0D && !blockposition.a((IPosition) (new Vec3D((double) f, (double) k, (double) f1)), 24.0D)) {
+                                    if (d0 > 576.0D && !blockposition.a((IPosition) (new Vec3D((double) f, (double) k, (double) f1)), 24.0D) && worldserver.isLoadedAndInBounds(blockposition_mutableblockposition)) { // Paper - don't load chunks for mob spawn
                                         ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(blockposition_mutableblockposition);
 
                                         if (Objects.equals(chunkcoordintpair, chunk.getPos()) || worldserver.getChunkProvider().a(chunkcoordintpair)) {