From 5d6a52b580d179bcd59043c97967d4e500819a61 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 16 Aug 2018 17:36:41 -0400
Subject: [PATCH] Ensure chunks are always loaded on hard position sets

Player Movement, Entity Creation and Teleportation move
entities with a very "You are here, no debate" change, making
the server register them as there, regardless if that chunk was
loaded or not.

It appears possible that with hack clients and lag, a player
may be able to move fast enough to move into an unloaded
chunk and get into a buggy state.

To prevent this, we will ensure a chunk is always loaded,
guaranteeing that the entity will be properly registered
into its new home comfortably.

diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 7b07fe1990..de34a70e9b 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1364,6 +1364,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
             this.lastYaw -= 360.0F;
         }
 
+        world.getChunkAt((int) Math.floor(this.locX) >> 4, (int) Math.floor(this.locZ) >> 4); // Paper - ensure chunk is always loaded
         this.setPosition(this.locX, this.locY, this.locZ);
         this.setYawPitch(f, f1);
     }
-- 
2.18.0