From 6f567dd6ea759b3af52c4ec8096ea256858ba361 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 22 Jan 2017 18:07:56 -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

This is not tied to the maxEntityCramming rule. Cramming will still apply
just as it does in Vanilla, but entity pushing logic will be capped.

You can set this to 0 to disable collisions.

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index f164844f..751551f1 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -322,4 +322,10 @@ public class PaperWorldConfig {
             log("Treasure Maps will return already discovered locations");
         }
     }
+
+    public int maxCollisionsPerEntity;
+    private void maxEntityCollision() {
+        maxCollisionsPerEntity = getInt( "max-entity-collisions", this.spigotConfig.getInt("max-entity-collisions", 8) );
+        log( "Max Entity Collisions: " + maxCollisionsPerEntity );
+    }
 }
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 1c8958d1..4f8e10b8 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -188,6 +188,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
     public final org.spigotmc.ActivationRange.ActivationType activationType = org.spigotmc.ActivationRange.initializeEntityActivationType(this);
     public final boolean defaultActivationState;
     public long activatedTick = Integer.MIN_VALUE;
+    protected int numCollisions = 0; // Paper
     public void inactiveTick() { }
     // Spigot end
 
diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 2775afc3..74de19bb 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -2623,8 +2623,11 @@ public abstract class EntityLiving extends Entity {
                 }
             }
 
-            for (j = 0; j < list.size(); ++j) {
+            numCollisions = Math.max(0, numCollisions - world.paperConfig.maxCollisionsPerEntity); // Paper
+            for (j = 0; j < list.size() && numCollisions < world.paperConfig.maxCollisionsPerEntity; ++j) { // Paper
                 Entity entity = (Entity) list.get(j);
+                entity.numCollisions++; // Paper
+                numCollisions++; // Paper
 
                 this.C(entity);
             }
-- 
2.25.1.windows.1