From 7c3871ebd4902e631d039bb26b9b17eae7ce2cc1 Mon Sep 17 00:00:00 2001
From: Brokkonaut <hannos17@gmx.de>
Date: Tue, 25 Sep 2018 06:53:43 +0200
Subject: [PATCH] Avoid dimension id collisions

getDimensionId() returns the dimension id - 1. So without this patch
we would reuse an existing dimension id, if some other dimension was
unloaded before.

diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index de98e896c2..034716a20a 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -971,7 +971,7 @@ public final class CraftServer implements Server {
         boolean used = false;
         do {
             for (WorldServer server : console.getWorlds()) {
-                used = server.dimension.getDimensionID() == dimension;
+                used = server.dimension.getDimensionID() + 1 == dimension; // Paper - getDimensionID returns the dimension - 1, so we have to add 1
                 if (used) {
                     dimension++;
                     break;
-- 
2.21.0