From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 21 Sep 2016 22:54:28 -0400
Subject: [PATCH] Chunk registration fixes

World checks and the Chunk Add logic are inconsistent on how Y > 256, < 0, is treated

Keep them consistent

diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
index 81a7278915eef762e1ddb296be4a73ac6450d44e..173388ca55bd15ba88f730ec9108f738740d64c5 100644
--- a/src/main/java/net/minecraft/server/WorldServer.java
+++ b/src/main/java/net/minecraft/server/WorldServer.java
@@ -728,7 +728,7 @@ public class WorldServer extends World implements GeneratorAccessSeed {
         if (entity.ck()) {
             this.getMethodProfiler().enter("chunkCheck");
             int i = MathHelper.floor(entity.locX() / 16.0D);
-            int j = MathHelper.floor(entity.locY() / 16.0D);
+            int j =  Math.min(15, Math.max(0, MathHelper.floor(entity.locY() / 16.0D))); // Paper - stay consistent with chunk add/remove behavior
             int k = MathHelper.floor(entity.locZ() / 16.0D);
 
             if (!entity.inChunk || entity.chunkX != i || entity.chunkY != j || entity.chunkZ != k) {