limit the range at which we'll consider an attackable target

This patch aims to ensure that MCP World#getNearestAttackablePlayer
will not trigger chunk loads due to PathfinderGoalNearestAttackableTarget
performing a ray trace operation by pre-checking the maximum limit;

Given that the implementation shows that the limit should only ever
decrease when set, allowing us to skip further checks earlier on
when looking for an attackable entity

Spigot-API-Patches/0032-Add-handshake-event-to-allow-plugins-to-handle-clien.patch

@@ -1,4 +1,4 @@
-From 4e0abf8c461a8e517fa30a281d90f8c60bd5686a Mon Sep 17 00:00:00 2001
+From ee3ad1b0cf85252211cdb2811557bfb7da695370 Mon Sep 17 00:00:00 2001
 From: kashike <kashike@vq.lc>
 Date: Wed, 13 Apr 2016 20:20:18 -0700
 Subject: [PATCH] Add handshake event to allow plugins to handle client
@@ -223,5 +223,5 @@ index 00000000..e44d03a2
 +    }
 +}
 -- 
-2.18.0
+2.19.1
 

Spigot-API-Patches/0033-Arrow-pickup-rule-API.patch

@@ -1,4 +1,4 @@
-From 57f8f2e8bfc9419a07a28ad20fb52c13ee3e5562 Mon Sep 17 00:00:00 2001
+From 5639eb8d022329ed99bb9f92f8dbe416d5e4f377 Mon Sep 17 00:00:00 2001
 From: Jedediah Smith <jedediah@silencegreys.com>
 Date: Fri, 4 Mar 2016 03:13:18 -0500
 Subject: [PATCH] Arrow pickup rule API
@@ -48,5 +48,5 @@ index 99814eee..34dde443 100644
 +    // Paper end
  }
 -- 
-2.18.0
+2.19.1
 

Spigot-Server-Patches/0413-limit-the-range-at-which-we-ll-consider-an-attackabl.patch

@@ -0,0 +1,35 @@
+From 9615b6f9aa28294eb6338baf0d29e2e5fc1921bb Mon Sep 17 00:00:00 2001
+From: Shane Freeder <theboyetronic@gmail.com>
+Date: Tue, 13 Nov 2018 14:01:00 +0000
+Subject: [PATCH] limit the range at which we'll consider an attackable target
+
+This patch aims to ensure that MCP World#getNearestAttackablePlayer
+will not trigger chunk loads due to PathfinderGoalNearestAttackableTarget
+performing a ray trace operation by pre-checking the maximum limit;
+
+Given that the implementation shows that the limit should only ever
+decrease when set, allowing us to skip further checks earlier on
+when looking for an attackable entity
+
+diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
+index cdbb247da..027871c00 100644
+--- a/src/main/java/net/minecraft/server/World.java
++++ b/src/main/java/net/minecraft/server/World.java
+@@ -2795,8 +2795,13 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
+         for (int i = 0; i < this.players.size(); ++i) {
+             EntityHuman entityhuman1 = (EntityHuman) this.players.get(i);
+ 
++            // Paper start
++            // move distance check up, if set, check distance^2 is less than XZlimit^2, continue
++            // 4th method param is XZlimit (at least at the time of commit)
++            double d6 = entityhuman1.d(d0, entityhuman1.locY, d2);
++            if (d3 < 0.0D || d6 < d3 * d3)
+             if (!entityhuman1.abilities.isInvulnerable && entityhuman1.isAlive() && !entityhuman1.isSpectator() && (predicate == null || predicate.test(entityhuman1))) {
+-                double d6 = entityhuman1.d(d0, entityhuman1.locY, d2);
++                // Paper end
+                 double d7 = d3;
+ 
+                 if (entityhuman1.isSneaking()) {
+-- 
+2.19.1
+