remove PM resource interaction from StartGamePacket

also lose the cache, because it's not very useful ...

src/data/bedrock/LegacyItemIdToStringIdMap.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\data\bedrock;
+
+use pocketmine\utils\AssumptionFailedError;
+use pocketmine\utils\SingletonTrait;
+use function file_get_contents;
+use function is_array;
+use function is_int;
+use function is_string;
+use function json_decode;
+
+final class LegacyItemIdToStringIdMap extends LegacyToStringBidirectionalIdMap{
+	use SingletonTrait;
+
+	public function __construct(){
+		parent::__construct(\pocketmine\RESOURCE_PATH . 'vanilla/item_id_map.json');
+	}
+}

src/network/mcpe/handler/PreSpawnPacketHandler.php

@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\network\mcpe\handler;
 
+use pocketmine\data\bedrock\LegacyItemIdToStringIdMap;
 use pocketmine\network\mcpe\convert\RuntimeBlockMapping;
 use pocketmine\network\mcpe\NetworkSession;
 use pocketmine\network\mcpe\protocol\RequestChunkRadiusPacket;
@@ -78,7 +79,7 @@ class PreSpawnPacketHandler extends PacketHandler{
 		$pk->levelId = "";
 		$pk->worldName = $this->server->getMotd();
 		$pk->blockTable = RuntimeBlockMapping::getInstance()->getStartGamePaletteCache();
-
+		$pk->itemTable = LegacyItemIdToStringIdMap::getInstance()->getStringToLegacyMap(); //TODO: check if this is actually needed
 		$this->session->sendDataPacket($pk);
 
 		$this->session->sendDataPacket(StaticPacketCache::getInstance()->getAvailableActorIdentifiers());

src/network/mcpe/protocol/StartGamePacket.php

@@ -38,9 +38,6 @@ use const pocketmine\RESOURCE_PATH;
 class StartGamePacket extends DataPacket implements ClientboundPacket{
 	public const NETWORK_ID = ProtocolInfo::START_GAME_PACKET;
 
-	/** @var string|null */
-	private static $itemTableCache = null;
-
 	/** @var int */
 	public $entityUniqueId;
 	/** @var int */
@@ -155,10 +152,10 @@ class StartGamePacket extends DataPacket implements ClientboundPacket{
 	 */
 	public $blockTable;
 	/**
-	 * @var int[]|null string (name) => int16 (legacyID)
+	 * @var int[] string (name) => int16 (legacyID)
-	 * @phpstan-var array<string, int>|null
+	 * @phpstan-var array<string, int>
 	 */
-	public $itemTable = null;
+	public $itemTable = [];
 
 	protected function decodePayload(NetworkBinaryStream $in) : void{
 		$this->entityUniqueId = $in->getEntityUniqueId();
@@ -285,14 +282,7 @@ class StartGamePacket extends DataPacket implements ClientboundPacket{
 
 		$out->put($this->blockTable->getEncodedNbt());
 
-		if($this->itemTable === null){
-			if(self::$itemTableCache === null){
-				self::$itemTableCache = self::serializeItemTable(json_decode(file_get_contents(RESOURCE_PATH . '/vanilla/item_id_map.json'), true));
-			}
-			$out->put(self::$itemTableCache);
-		}else{
 		$out->put(self::serializeItemTable($this->itemTable));
-		}
 
 		$out->putString($this->multiplayerCorrelationId);
 	}