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 11cfe63c101f5d76d3481a3163dbaec22685ccce..b0caf14a196cd8c3a02d8e931a08857173ffb4da 100644
--- a/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
+++ b/src/main/java/net/minecraft/world/entity/projectile/Projectile.java
@@ -58,6 +58,18 @@ public abstract class Projectile extends Entity {
             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;