Paper/patches/server/0124-Cap-Entity-Collisions.patch

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 a914d2906ae7433164d7f439a0f2f0d781b14747..05cb13a5636f82d48bf0bd8b9d27abdd80a8df71 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -393,6 +393,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, S
     public long activatedTick = Integer.MIN_VALUE;
     public void inactiveTick() { }
     // Spigot end
+    protected int numCollisions = 0; // Paper - Cap entity collisions
     // Paper start - Entity origin API
     @javax.annotation.Nullable
     private org.bukkit.util.Vector origin;
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index ed8e0f5ca865dcde73a886e65f0fd1d7d4e7ac05..a799b64e9d655e7eba509e9930e623a88bbb0389 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3348,10 +3348,12 @@ 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 - Cap entity collisions
 
-                while (iterator1.hasNext()) {
+                while (iterator1.hasNext() && this.numCollisions < this.level().paperConfig().collisions.maxEntityCollisions) { // Paper - Cap entity collisions
                     Entity entity1 = (Entity) iterator1.next();
-
+                    entity1.numCollisions++; // Paper - Cap entity collisions
+                    this.numCollisions++; // Paper - Cap entity collisions
                     this.doPush(entity1);
                 }
             }