From 50a4a79f619cb15deeec13ae06744cc3bb23082a Mon Sep 17 00:00:00 2001
From: CraftBukkit/Spigot <noreply+git-craftbukkit@papermc.io>
Date: Mon, 20 Jul 2015 16:18:08 +1000
Subject: [PATCH] Prevent an Entity from riding itself.

By: Xor Boole <mcyoung@mit.edu>
---
 .../main/java/org/bukkit/craftbukkit/entity/CraftEntity.java    | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 705381f9f3..8f5c0587ff 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -1,5 +1,6 @@
 package org.bukkit.craftbukkit.entity;
 
+import com.google.common.base.Preconditions;
 import java.util.List;
 import java.util.Set;
 import java.util.UUID;
@@ -301,6 +302,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
     }
 
     public boolean setPassenger(org.bukkit.entity.Entity passenger) {
+        Preconditions.checkArgument(!this.equals(passenger), "Entity cannot ride itself.");
         if (passenger instanceof CraftEntity) {
             ((CraftEntity) passenger).getHandle().mount(getHandle());
             return true;