From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 17 Oct 2018 19:17:27 -0400
Subject: [PATCH] MC-50319: Check other worlds for shooter of projectiles

Say a player shoots an arrow through a nether portal, the game
would lose the shooter for determining things such as Player Kills,
because the entity is in another world.

If the projectile fails to find the shooter in the current world, check
other worlds.

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 f49dd279ba9e8970f116f956466feb072c4f8420..e5da57b35cd82ee7b4e844cfe74289a71d38779a 100644
--- a/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
+++ b/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
@@ -60,6 +60,18 @@ public abstract class Projectile extends Entity implements TraceableEntity {
             return this.cachedOwner;
         } else if (this.ownerUUID != null && this.level() instanceof ServerLevel) {
             this.cachedOwner = ((ServerLevel) this.level()).getEntity(this.ownerUUID);
+            // Paper start - check all worlds
+            if (this.cachedOwner == null) {
+                for (final ServerLevel level : this.level().getServer().getAllLevels()) {
+                    if (level == this.level()) continue;
+                    final Entity entity = level.getEntity(this.ownerUUID);
+                    if (entity != null) {
+                        this.cachedOwner = entity;
+                        break;
+                    }
+                }
+            }
+            // Paper end
             return this.cachedOwner;
         } else {
             return null;