Paper/patches/server/0130-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 6d76be16ba1b35a65b851c2c861093c9998fcc61..7d839daeca968df2044bf2071bf1b5ff2b2aa3d6 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -382,6 +382,7 @@ 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 e004dffee9f1efe44c78f9b2e938b98cc4b2b847..2cd9c02fd664e263d9dae030d2c438a082c9e1b4 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3277,8 +3277,11 @@ public abstract class LivingEntity extends Entity implements Attackable {
                     }
                 }
 
-                for (j = 0; j < list.size(); ++j) {
+            this.numCollisions = Math.max(0, this.numCollisions - this.level.paperConfig().collisions.maxEntityCollisions); // Paper
+            for (j = 0; j < list.size() && this.numCollisions < this.level.paperConfig().collisions.maxEntityCollisions; ++j) { // Paper
                     Entity entity = (Entity) list.get(j);
+                entity.numCollisions++; // Paper
+                this.numCollisions++; // Paper
 
                     this.doPush(entity);
                 }