From b1e0831238da2e176d7af809832d3e7466946d3f Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Fri, 31 Jan 2014 11:18:34 -0500
Subject: [PATCH] Cap Entity Collisions

Limit a single entity to colliding a max of configurable times per tick.
This will alleviate issues where living entities are hoarded in 1x1 pens.

diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index b930c0d..82accf4 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1052,6 +1052,7 @@ public abstract class Entity implements ICommandListener {
 
     public void d(EntityHuman entityhuman) {}
 
+    int numCollisions = 0; // Spigot
     public void collide(Entity entity) {
         if (entity.passenger != this && entity.vehicle != this) {
             if (!entity.noclip && !this.noclip) {
diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index c6244a5..99b120a 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -1675,7 +1675,9 @@ public abstract class EntityLiving extends Entity {
         }));
 
         if (this.ad() && !list.isEmpty()) { // Spigot: Add this.ad() condition
+            numCollisions -= world.spigotConfig.maxCollisionsPerEntity; // Spigot
             for (int i = 0; i < list.size(); ++i) {
+                if (numCollisions > world.spigotConfig.maxCollisionsPerEntity) { break; } // Spigot
                 Entity entity = (Entity) list.get(i);
 
                 // TODO better check now?
@@ -1685,8 +1687,11 @@ public abstract class EntityLiving extends Entity {
                 }
                 // CraftBukkit end
 
+                entity.numCollisions++; // Spigot
+                numCollisions++; // Spigot
                 this.s(entity);
             }
+            numCollisions = 0; // Spigot
         }
 
     }
diff --git a/src/main/java/org/spigotmc/SpigotWorldConfig.java b/src/main/java/org/spigotmc/SpigotWorldConfig.java
index c7cb20c..76ded26 100644
--- a/src/main/java/org/spigotmc/SpigotWorldConfig.java
+++ b/src/main/java/org/spigotmc/SpigotWorldConfig.java
@@ -273,4 +273,11 @@ public class SpigotWorldConfig
         maxBulkChunk = getInt( "max-bulk-chunks", 10 );
         log( "Sending up to " + maxBulkChunk + " chunks per packet" );
     }
+
+    public int maxCollisionsPerEntity;
+    private void maxEntityCollision()
+    {
+        maxCollisionsPerEntity = getInt( "max-entity-collisions", 8 );
+        log( "Max Entity Collisions: " + maxCollisionsPerEntity );
+    }
 }
-- 
2.1.0