From cbb02b848932ae2be731c85cba1be561c6bedca2 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 19 Dec 2016 23:07:42 -0500
Subject: [PATCH] Prevent Pathfinding out of World Border

This prevents Entities from trying to run outside of the World Border

diff --git a/src/main/java/net/minecraft/server/NavigationAbstract.java b/src/main/java/net/minecraft/server/NavigationAbstract.java
index ed69eaa176..a473c03b9d 100644
--- a/src/main/java/net/minecraft/server/NavigationAbstract.java
+++ b/src/main/java/net/minecraft/server/NavigationAbstract.java
@@ -95,6 +95,7 @@ public abstract class NavigationAbstract {
     @Nullable
     protected PathEntity a(BlockPosition blockposition, double d0, double d1, double d2, int i, boolean flag) { return this.a(blockposition, null, d0, d1, d2, i, flag); }
     @Nullable protected PathEntity a(BlockPosition blockposition, Entity target, double d0, double d1, double d2, int i, boolean flag) {
+        if (!getEntity().getWorld().getWorldBorder().isInBounds(blockposition)) return null; // Paper - don't path out of world border
         if (this.a.locY < 0.0D) {
             return null;
         } else if (!this.a()) {
-- 
2.21.0