From 06c4f31db7046f23e26e3a15119d0cd8f2c68fd1 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Fri, 14 Sep 2018 11:05:51 +0100
Subject: [PATCH] Server: Account for later levels being unloaded by earlier
 levels' ticking function in checkTickUpdates() should fix #2434

This happens when a plugin causes a level to be unloaded during an event fired on level tick.
---
 src/pocketmine/Server.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/pocketmine/Server.php b/src/pocketmine/Server.php
index bb9bd2f5eb..0203e1a8e3 100644
--- a/src/pocketmine/Server.php
+++ b/src/pocketmine/Server.php
@@ -2352,7 +2352,11 @@ class Server{
 		}
 
 		//Do level ticks
-		foreach($this->getLevels() as $level){
+		foreach($this->levels as $k => $level){
+			if(!isset($this->levels[$k])){
+				// Level unloaded during the tick of a level earlier in this loop, perhaps by plugin
+				continue;
+			}
 			if($level->getTickRate() > $this->baseTickRate and --$level->tickRateCounter > 0){
 				continue;
 			}