From 4f25ab10e99308fbd9b7f977405f4d52b2695a5e Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Tue, 22 Feb 2022 16:45:21 +0000
Subject: [PATCH] InventoryManager: Do not sync slots the client correctly
 predicted during using items closes #4825

---
 src/network/mcpe/InventoryManager.php            | 13 +++++++++++++
 src/network/mcpe/handler/InGamePacketHandler.php |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/src/network/mcpe/InventoryManager.php b/src/network/mcpe/InventoryManager.php
index e7e53b4d3..2c2ecc8c8 100644
--- a/src/network/mcpe/InventoryManager.php
+++ b/src/network/mcpe/InventoryManager.php
@@ -50,6 +50,7 @@ use pocketmine\network\mcpe\protocol\types\BlockPosition;
 use pocketmine\network\mcpe\protocol\types\inventory\ContainerIds;
 use pocketmine\network\mcpe\protocol\types\inventory\CreativeContentEntry;
 use pocketmine\network\mcpe\protocol\types\inventory\ItemStackWrapper;
+use pocketmine\network\mcpe\protocol\types\inventory\NetworkInventoryAction;
 use pocketmine\network\mcpe\protocol\types\inventory\WindowTypes;
 use pocketmine\player\Player;
 use pocketmine\utils\AssumptionFailedError;
@@ -145,6 +146,18 @@ class InventoryManager{
 		}
 	}
 
+	/**
+	 * @param NetworkInventoryAction[] $networkInventoryActions
+	 */
+	public function addPredictedSlotChanges(array $networkInventoryActions) : void{
+		foreach($networkInventoryActions as $action){
+			if($action->sourceType === NetworkInventoryAction::SOURCE_CONTAINER && isset($this->windowMap[$action->windowId])){
+				//this won't cover stuff like crafting grid due to too much magic
+				$this->initiatedSlotChanges[$action->windowId][$action->inventorySlot] = TypeConverter::getInstance()->netItemStackToCore($action->newItem->getItemStack());
+			}
+		}
+	}
+
 	public function onCurrentWindowChange(Inventory $inventory) : void{
 		$this->onCurrentWindowRemove();
 		$this->add($this->lastInventoryNetworkId = max(ContainerIds::FIRST, ($this->lastInventoryNetworkId + 1) % self::RESERVED_WINDOW_ID_RANGE_START), $inventory);
diff --git a/src/network/mcpe/handler/InGamePacketHandler.php b/src/network/mcpe/handler/InGamePacketHandler.php
index dc2a5e468..f2e0eafb4 100644
--- a/src/network/mcpe/handler/InGamePacketHandler.php
+++ b/src/network/mcpe/handler/InGamePacketHandler.php
@@ -411,6 +411,7 @@ class InGamePacketHandler extends PacketHandler{
 
 	private function handleUseItemTransaction(UseItemTransactionData $data) : bool{
 		$this->player->selectHotbarSlot($data->getHotbarSlot());
+		$this->inventoryManager->addPredictedSlotChanges($data->getActions());
 
 		switch($data->getActionType()){
 			case UseItemTransactionData::ACTION_CLICK_BLOCK:
@@ -500,6 +501,7 @@ class InGamePacketHandler extends PacketHandler{
 		}
 
 		$this->player->selectHotbarSlot($data->getHotbarSlot());
+		$this->inventoryManager->addPredictedSlotChanges($data->getActions());
 
 		//TODO: use transactiondata for rollbacks here
 		switch($data->getActionType()){
@@ -520,6 +522,7 @@ class InGamePacketHandler extends PacketHandler{
 
 	private function handleReleaseItemTransaction(ReleaseItemTransactionData $data) : bool{
 		$this->player->selectHotbarSlot($data->getHotbarSlot());
+		$this->inventoryManager->addPredictedSlotChanges($data->getActions());
 
 		//TODO: use transactiondata for rollbacks here (resending entire inventory is very wasteful)
 		switch($data->getActionType()){