From 3ea8d27a3bdcf7866119928b4e0ee9d498bfdfe3 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Fri, 7 Apr 2023 22:55:27 +0100
Subject: [PATCH] HandlerList: improve listener list development to make way
 for #5678

---
 src/event/EventPriority.php |  2 ++
 src/event/HandlerList.php   | 22 ++++++++++++----------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/event/EventPriority.php b/src/event/EventPriority.php
index cdeb3136a..99c71faff 100644
--- a/src/event/EventPriority.php
+++ b/src/event/EventPriority.php
@@ -32,6 +32,8 @@ use function mb_strtoupper;
  * LOWEST -> LOW -> NORMAL -> HIGH -> HIGHEST -> MONITOR
  *
  * MONITOR events should not change the event outcome or contents
+ *
+ * WARNING: If these values are changed, handler sorting in HandlerList::getListenerList() may need to be updated.
  */
 final class EventPriority{
 
diff --git a/src/event/HandlerList.php b/src/event/HandlerList.php
index 7774ea840..0bc207560 100644
--- a/src/event/HandlerList.php
+++ b/src/event/HandlerList.php
@@ -24,8 +24,10 @@ declare(strict_types=1);
 namespace pocketmine\event;
 
 use pocketmine\plugin\Plugin;
-use function array_fill_keys;
+use function array_merge;
+use function krsort;
 use function spl_object_id;
+use const SORT_NUMERIC;
 
 class HandlerList{
 	/** @var RegisteredListener[][] */
@@ -48,8 +50,6 @@ class HandlerList{
 		for($list = $this; $list !== null; $list = $list->parentList){
 			$list->affectedHandlerCaches[spl_object_id($this->handlerCache)] = $this->handlerCache;
 		}
-
-		$this->handlerSlots = array_fill_keys(EventPriority::ALL, []);
 	}
 
 	/**
@@ -94,7 +94,7 @@ class HandlerList{
 	}
 
 	public function clear() : void{
-		$this->handlerSlots = array_fill_keys(EventPriority::ALL, []);
+		$this->handlerSlots = [];
 		$this->invalidateAffectedCaches();
 	}
 
@@ -132,15 +132,17 @@ class HandlerList{
 			$handlerLists[] = $currentList;
 		}
 
-		$listeners = [];
-		foreach(EventPriority::ALL as $priority){
-			foreach($handlerLists as $currentList){
-				foreach($currentList->getListenersByPriority($priority) as $registration){
-					$listeners[] = $registration;
-				}
+		$listenersByPriority = [];
+		foreach($handlerLists as $currentList){
+			foreach($currentList->handlerSlots as $priority => $listeners){
+				$listenersByPriority[$priority] = array_merge($listenersByPriority[$priority] ?? [], $listeners);
 			}
 		}
 
+		//TODO: why on earth do the priorities have higher values for lower priority?
+		krsort($listenersByPriority, SORT_NUMERIC);
+		$listeners = array_merge(...$listenersByPriority);
+
 		return $this->handlerCache->list = $listeners;
 	}
 }