From 0000000000000000000000000000000000000000 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/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 468111bb80e7756371d22eb831596c187538f0c1..b4c91cb985d3772c5b105b8d2267b51d7483e005 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -387,6 +387,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
     public void inactiveTick() { }
     // Spigot end
     // Paper start
+    protected int numCollisions = 0; // Paper
     @javax.annotation.Nullable
     private org.bukkit.util.Vector origin;
     @javax.annotation.Nullable
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 45d1b869b0aa2d12000a58c5c3cd1c8232429d36..a8d39b7257332ec8b3b711aab2c4b76a867e73bc 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3349,10 +3349,12 @@ public abstract class LivingEntity extends Entity implements Attackable {
                 }
 
                 Iterator iterator1 = list.iterator();
+                this.numCollisions = Math.max(0, this.numCollisions - this.level().paperConfig().collisions.maxEntityCollisions); // Paper
 
-                while (iterator1.hasNext()) {
+                while (iterator1.hasNext() && this.numCollisions < this.level().paperConfig().collisions.maxEntityCollisions) { // Paper
                     Entity entity1 = (Entity) iterator1.next();
-
+                    entity1.numCollisions++; // Paper
+                    this.numCollisions++; // Paper
                     this.doPush(entity1);
                 }
             }