Paper/patches/server/0187-Block-Enderpearl-Travel-Exploit.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 30 Apr 2018 17:15:26 -0400
Subject: [PATCH] Block Enderpearl Travel Exploit

Players are able to use alt accounts and enderpearls to travel
long distances utilizing the pearls in unloaded chunks and loading
the chunk later when convenient.

This disables that by not saving the thrower when the chunk is unloaded.

This is mainly useful for survival servers that do not allow freeform teleporting.

== AT ==
public net.minecraft.world.entity.projectile.Projectile cachedOwner
public net.minecraft.world.entity.projectile.Projectile ownerUUID

diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 87cd4d17d618cd9d69a38838a05dbe5d0fe807d4..f27472e03a6dc0781168c5862c57b501f7ae2dc9 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -2368,6 +2368,12 @@ public class ServerLevel extends Level implements WorldGenLevel {
 
         public void onTickingEnd(Entity entity) {
             ServerLevel.this.entityTickList.remove(entity);
+            // Paper start - Reset pearls when they stop being ticked
+            if (paperConfig().fixes.disableUnloadedChunkEnderpearlExploit && entity instanceof net.minecraft.world.entity.projectile.ThrownEnderpearl pearl) {
+                pearl.cachedOwner = null;
+                pearl.ownerUUID = null;
+            }
+            // Paper end - Reset pearls when they stop being ticked
         }
 
         public void onTrackingStart(Entity entity) {
diff --git a/src/main/java/net/minecraft/world/entity/projectile/Projectile.java b/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
index fbbb1fa3d5f4ace67fee96aa235cec3b39deb7b1..e432855ce79f69c0e91fa31e8f6c59a465b0d09e 100644
--- a/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
+++ b/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
@@ -101,6 +101,7 @@ public abstract class Projectile extends Entity implements TraceableEntity {
         if (nbt.hasUUID("Owner")) {
             this.ownerUUID = nbt.getUUID("Owner");
             this.cachedOwner = null;
+            if (this instanceof ThrownEnderpearl && this.level() != null && this.level().paperConfig().fixes.disableUnloadedChunkEnderpearlExploit) { this.ownerUUID = null; } // Paper - Reset pearls when they stop being ticked; Don't store shooter name for pearls to block enderpearl travel exploit
         }
 
         this.leftOwner = nbt.getBoolean("LeftOwner");