From 995b2e22adbabdca35486f446fde38c87b21b975 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 10 Sep 2018 23:56:36 -0400
Subject: [PATCH] Prevent Mob AI Rules from Loading Chunks


diff --git a/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java b/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java
index ce9318c575..541d97344e 100644
--- a/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java
+++ b/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java
@@ -12,11 +12,13 @@ public class PathfinderGoalRemoveBlock extends PathfinderGoalGotoTarget {
     private final Block g;
     private final EntityInsentient entity;
     private int i;
+    private World world; // Paper
 
     public PathfinderGoalRemoveBlock(Block block, EntityCreature entitycreature, double d0, int i) {
         super(entitycreature, d0, 24, i);
         this.g = block;
         this.entity = entitycreature;
+        this.world = entitycreature.world; // Paper
     }
 
     @Override
@@ -114,7 +116,9 @@ public class PathfinderGoalRemoveBlock extends PathfinderGoalGotoTarget {
 
     @Nullable
     private BlockPosition a(BlockPosition blockposition, IBlockAccess iblockaccess) {
-        if (iblockaccess.getType(blockposition).getBlock() == this.g) {
+        Block block = world.getBlockIfLoaded(blockposition); // Paper
+        if (block == null) return null; // Paper
+        if (block == this.g) { // Paper
             return blockposition;
         } else {
             BlockPosition[] ablockposition = new BlockPosition[] { blockposition.down(), blockposition.west(), blockposition.east(), blockposition.north(), blockposition.south(), blockposition.down().down()};
@@ -124,7 +128,7 @@ public class PathfinderGoalRemoveBlock extends PathfinderGoalGotoTarget {
             for (int j = 0; j < i; ++j) {
                 BlockPosition blockposition1 = ablockposition1[j];
 
-                if (iblockaccess.getType(blockposition1).getBlock() == this.g) {
+                if (world.getBlockIfLoaded(blockposition1) == this.g) { // Paper
                     return blockposition1;
                 }
             }
@@ -135,7 +139,8 @@ public class PathfinderGoalRemoveBlock extends PathfinderGoalGotoTarget {
 
     @Override
     protected boolean a(IWorldReader iworldreader, BlockPosition blockposition) {
-        Block block = iworldreader.getType(blockposition).getBlock();
+        Block block = world.getBlockIfLoaded(blockposition); // Paper
+        if (block == null) return false; // Paper
 
         return block == this.g && iworldreader.getType(blockposition.up()).isAir() && iworldreader.getType(blockposition.up(2)).isAir();
     }
diff --git a/src/main/java/net/minecraft/server/RandomPositionGenerator.java b/src/main/java/net/minecraft/server/RandomPositionGenerator.java
index 8340d6d25b..78eb1b39cf 100644
--- a/src/main/java/net/minecraft/server/RandomPositionGenerator.java
+++ b/src/main/java/net/minecraft/server/RandomPositionGenerator.java
@@ -93,6 +93,7 @@ public class RandomPositionGenerator {
                 }
 
                 blockposition1 = new BlockPosition((double) k1 + entitycreature.locX, (double) l1 + entitycreature.locY, (double) i2 + entitycreature.locZ);
+                if (!entitycreature.world.isLoaded(blockposition1)) continue; // Paper
                 if ((!flag1 || entitycreature.a(blockposition1)) && navigationabstract.a(blockposition1)) {
                     if (!flag) {
                         blockposition1 = a(blockposition1, entitycreature);
@@ -161,6 +162,7 @@ public class RandomPositionGenerator {
     }
 
     private static boolean b(BlockPosition blockposition, EntityCreature entitycreature) {
-        return entitycreature.world.getFluid(blockposition).a(TagsFluid.WATER);
+        Fluid fluid = entitycreature.world.getFluidIfLoaded(blockposition); // Paper
+        return fluid != null && fluid.a(TagsFluid.WATER); // Paper
     }
 }
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index 3f9ad25cbb..bebf5a6e19 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -645,6 +645,16 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
             return chunk.getType(blockposition);
         }
     }
+    // Paper start
+    public Fluid getFluidIfLoaded(BlockPosition blockposition) {
+        if (blockposition.isInvalidYLocation()) { // Paper
+            return getFluid(blockposition);
+        } else {
+            Chunk chunk = this.getChunkIfLoaded(blockposition);
+            return chunk != null ? chunk.getFluid(blockposition) : null;
+        }
+    }
+    // Paper end
 
     @Override
     public Fluid getFluid(BlockPosition blockposition) {
-- 
2.21.0