From 5a3105919b2b3188ffdda50e47f69a049c7bc181 Mon Sep 17 00:00:00 2001
From: CraftBukkit/Spigot <noreply+git-craftbukkit@papermc.io>
Date: Wed, 29 Dec 2021 10:48:15 +1100
Subject: [PATCH] Add self-riding check to Entity#addPassenger

By: md_5 <git@md-5.net>
---
 .../src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java | 1 +
 1 file changed, 1 insertion(+)

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 edd2276b69..f4049559dd 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
@@ -662,6 +662,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
     @Override
     public boolean addPassenger(org.bukkit.entity.Entity passenger) {
         Preconditions.checkArgument(passenger != null, "passenger == null");
+        Preconditions.checkArgument(!this.equals(passenger), "Entity cannot ride itself.");
 
         return ((CraftEntity) passenger).getHandle().startRiding(getHandle(), true);
     }