From 41fd03f329cd108381001dcb69d66ffa873e3bd9 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Fri, 19 Oct 2018 16:55:32 +0100
Subject: [PATCH] LightUpdate: fixed double-updated nodes not getting light
 propagated appropriately This can happen when a light source is removed and
 later encountering another light source to fill the gap. A higher light level
 may get set and then not propagated. This bug is difficult to explain, but
 fairly easy to reproduce.

---
 src/pocketmine/level/light/LightUpdate.php | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/pocketmine/level/light/LightUpdate.php b/src/pocketmine/level/light/LightUpdate.php
index 6e82d2f68..9934492a3 100644
--- a/src/pocketmine/level/light/LightUpdate.php
+++ b/src/pocketmine/level/light/LightUpdate.php
@@ -106,6 +106,8 @@ abstract class LightUpdate{
 		while(!$this->spreadQueue->isEmpty()){
 			list($x, $y, $z) = $this->spreadQueue->dequeue();
 
+			unset($this->spreadVisited[Level::blockHash($x, $y, $z)]);
+
 			if(!$this->subChunkHandler->moveTo($x, $y, $z)){
 				continue;
 			}