Store ender chest viewer count on the tile, instead of relying on the inventory's viewer count (#4238)

Fixes #4021

src/block/EnderChest.php

@@ -53,6 +53,7 @@ class EnderChest extends Transparent{
 		if($player instanceof Player){
 			$enderChest = $this->pos->getWorld()->getTile($this->pos);
 			if($enderChest instanceof TileEnderChest and $this->getSide(Facing::UP)->isTransparent()){
+				$enderChest->setViewerCount($enderChest->getViewerCount() + 1);
 				$player->setCurrentWindow(new EnderChestInventory($this->pos, $player->getEnderInventory()));
 			}
 		}

src/block/inventory/AnimatedBlockInventoryTrait.php

@@ -30,6 +30,10 @@ use function count;
 trait AnimatedBlockInventoryTrait{
 	use BlockInventoryTrait;
 
+	public function getViewerCount() : int{
+		return count($this->getViewers());
+	}
+
 	/**
 	 * @return Player[]
 	 * @phpstan-return array<int, Player>
@@ -43,7 +47,7 @@ trait AnimatedBlockInventoryTrait{
 	public function onOpen(Player $who) : void{
 		parent::onOpen($who);
 
-		if(count($this->getViewers()) === 1 and $this->getHolder()->isValid()){
+		if($this->getHolder()->isValid() and $this->getViewerCount() === 1){
 			//TODO: this crap really shouldn't be managed by the inventory
 			$this->animateBlock(true);
 			$this->getHolder()->getWorld()->addSound($this->getHolder()->add(0.5, 0.5, 0.5), $this->getOpenSound());
@@ -53,7 +57,7 @@ trait AnimatedBlockInventoryTrait{
 	abstract protected function animateBlock(bool $isOpen) : void;
 
 	public function onClose(Player $who) : void{
-		if(count($this->getViewers()) === 1 and $this->getHolder()->isValid()){
+		if($this->getHolder()->isValid() and $this->getViewerCount() === 1){
 			//TODO: this crap really shouldn't be managed by the inventory
 			$this->animateBlock(false);
 			$this->getHolder()->getWorld()->addSound($this->getHolder()->add(0.5, 0.5, 0.5), $this->getCloseSound());

src/block/inventory/EnderChestInventory.php

@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\block\inventory;
 
+use pocketmine\block\tile\EnderChest;
 use pocketmine\inventory\BaseInventory;
 use pocketmine\inventory\CallbackInventoryListener;
 use pocketmine\inventory\Inventory;
@@ -85,6 +86,14 @@ class EnderChestInventory extends BaseInventory implements BlockInventory{
 		$this->inventory->setContents($items);
 	}
 
+	public function getViewerCount() : int{
+		$enderChest = $this->getHolder()->getWorld()->getTile($this->getHolder());
+		if(!$enderChest instanceof EnderChest){
+			return 0;
+		}
+		return $enderChest->getViewerCount();
+	}
+
 	protected function getOpenSound() : Sound{
 		return new EnderChestOpenSound();
 	}
@@ -102,6 +111,10 @@ class EnderChestInventory extends BaseInventory implements BlockInventory{
 
 	public function onClose(Player $who) : void{
 		$this->animatedBlockInventoryTrait_onClose($who);
+		$enderChest = $this->getHolder()->getWorld()->getTile($this->getHolder());
+		if($enderChest instanceof EnderChest){
+			$enderChest->setViewerCount($enderChest->getViewerCount() - 1);
+		}
 		if($who === $this->inventory->getHolder()){
 			$this->inventory->getListeners()->remove($this->inventoryListener);
 			$this->inventoryListener = CallbackInventoryListener::onAnyChange(static function() : void{}); //break cyclic reference

src/block/tile/EnderChest.php

@@ -27,6 +27,19 @@ use pocketmine\nbt\tag\CompoundTag;
 
 class EnderChest extends Spawnable{
 
+	protected int $viewerCount = 0;
+
+	public function getViewerCount() : int{
+		return $this->viewerCount;
+	}
+
+	public function setViewerCount(int $viewerCount) : void{
+		if($viewerCount < 0){
+			throw new \InvalidArgumentException('Viewer count cannot be negative');
+		}
+		$this->viewerCount = $viewerCount;
+	}
+
 	public function readSaveData(CompoundTag $nbt) : void{
 
 	}