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 621ecd0f3cac52d3e4cecd003c67401ec7f0a6f7..a85175190c1ebb14b496a0bfe2f7136e06d0072c 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;