Revamp Tile creation (again)

This breaks down the handling of tile creation even further.
- Introduced a static Tile::override() method to allow overriding the construction class for a specific type of chest. This applies to classes as opposed to save IDs, so you can override Chest::class with MyCustomChest::class and it will take effect for any Chest save ID.
- Removed MCPE stringy save ID constants from public Tile interface. These are now only used for creating saved tiles from a stored chunk, and saving them.
- Renamed Tile::registerTile() to register()
- Tile::create() and Tile::createFromItem() now accept a class parameter instead of a stringy save ID.
- Tile::create() and Tile::createFromItem() were changed to throw \InvalidArgumentException on unknown/unregistered tile types. They also now never return null, but always (except in exception cases) return an object which is an instanceof the base class specified.

src/pocketmine/block/Bed.php

@@ -86,13 +86,10 @@ class Bed extends Transparent{
 	public function writeStateToWorld() : void{
 		parent::writeStateToWorld();
 		//extra block properties storage hack
-		$tile = Tile::create(Tile::BED, $this->getLevel(), $this->asVector3());
+		/** @var TileBed $tile */
-		if($tile !== null){
+		$tile = Tile::create(TileBed::class, $this->getLevel(), $this->asVector3());
-			if($tile instanceof TileBed){
+		$tile->setColor($this->color);
-				$tile->setColor($this->color);
+		$this->level->addTile($tile);
-			}
-			$this->level->addTile($tile);
-		}
 	}
 
 	public function getHardness() : float{

src/pocketmine/block/Chest.php

@@ -72,7 +72,8 @@ class Chest extends Transparent{
 	}
 
 	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
-		$chest = null;
+		/** @var TileChest|null $pair */
+		$pair = null;
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
@@ -85,21 +86,20 @@ class Chest extends Transparent{
 			if($c instanceof Chest and $c->isSameType($this) and $c->facing === $this->facing){
 				$tile = $this->getLevel()->getTile($c);
 				if($tile instanceof TileChest and !$tile->isPaired()){
-					$chest = $tile;
+					$pair = $tile;
 					break;
 				}
 			}
 		}
 
 		if(parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player)){
-			$tile = Tile::createFromItem(Tile::CHEST, $this->getLevel(), $this->asVector3(), $item);
+			/** @var TileChest $tile */
-			if($tile !== null){
+			$tile = Tile::createFromItem(TileChest::class, $this->getLevel(), $this->asVector3(), $item);
-				$this->level->addTile($tile);
+			$this->level->addTile($tile);
-			}
 
-			if($chest instanceof TileChest and $tile instanceof TileChest){
+			if($pair instanceof TileChest){
-				$chest->pairWith($tile);
+				$pair->pairWith($tile);
-				$tile->pairWith($chest);
+				$tile->pairWith($pair);
 			}
 
 			return true;

src/pocketmine/block/EnchantingTable.php

@@ -30,6 +30,7 @@ use pocketmine\math\AxisAlignedBB;
 use pocketmine\math\Facing;
 use pocketmine\math\Vector3;
 use pocketmine\Player;
+use pocketmine\tile\EnchantTable as TileEnchantingTable;
 use pocketmine\tile\Tile;
 
 class EnchantingTable extends Transparent{
@@ -42,9 +43,7 @@ class EnchantingTable extends Transparent{
 
 	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
 		if(parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player)){
-			if(($tile = Tile::createFromItem(Tile::ENCHANT_TABLE, $this->getLevel(), $this->asVector3(), $item)) !== null){
+			$this->level->addTile(Tile::createFromItem(TileEnchantingTable::class, $this->getLevel(), $this->asVector3(), $item));
-				$this->level->addTile($tile);
-			}
 			return true;
 		}
 

src/pocketmine/block/EnderChest.php

@@ -66,9 +66,7 @@ class EnderChest extends Chest{
 		}
 
 		if(Block::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player)){
-			if(($tile = Tile::createFromItem(Tile::ENDER_CHEST, $this->getLevel(), $this->asVector3(), $item)) !== null){
+			$this->level->addTile(Tile::createFromItem(TileEnderChest::class, $this->getLevel(), $this->asVector3(), $item));
-				$this->level->addTile($tile);
-			}
 			return true;
 		}
 

src/pocketmine/block/FlowerPot.php

@@ -69,9 +69,7 @@ class FlowerPot extends Flowable{
 		}
 
 		if(parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player)){
-			if(($tile = Tile::createFromItem(Tile::FLOWER_POT, $this->getLevel(), $this->asVector3(), $item)) !== null){
+			$this->level->addTile(Tile::createFromItem(TileFlowerPot::class, $this->getLevel(), $this->asVector3(), $item));
-				$this->level->addTile($tile);
-			}
 			return true;
 		}
 

src/pocketmine/block/Furnace.php

@@ -99,9 +99,7 @@ class Furnace extends Solid{
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
 		if(parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player)){
-			if(($tile = Tile::createFromItem(Tile::FURNACE, $this->getLevel(), $this->asVector3(), $item)) !== null){
+			$this->level->addTile(Tile::createFromItem(TileFurnace::class, $this->getLevel(), $this->asVector3(), $item));
-				$this->level->addTile($tile);
-			}
 			return true;
 		}
 

src/pocketmine/block/ItemFrame.php

@@ -85,9 +85,7 @@ class ItemFrame extends Flowable{
 		$this->facing = $face;
 
 		if(parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player)){
-			if(($tile = Tile::createFromItem(Tile::ITEM_FRAME, $this->getLevel(), $this->asVector3(), $item)) !== null){
+			$this->level->addTile(Tile::createFromItem(TileItemFrame::class, $this->getLevel(), $this->asVector3(), $item));
-				$this->level->addTile($tile);
-			}
 			return true;
 		}
 

src/pocketmine/block/SignPost.php

@@ -28,6 +28,7 @@ use pocketmine\math\AxisAlignedBB;
 use pocketmine\math\Facing;
 use pocketmine\math\Vector3;
 use pocketmine\Player;
+use pocketmine\tile\Sign as TileSign;
 use pocketmine\tile\Tile;
 
 class SignPost extends Transparent{
@@ -82,9 +83,7 @@ class SignPost extends Transparent{
 			}
 
 			if($ret){
-				if(($tile = Tile::createFromItem(Tile::SIGN, $this->getLevel(), $this->asVector3(), $item)) !== null){
+				$this->level->addTile(Tile::createFromItem(TileSign::class, $this->getLevel(), $this->asVector3(), $item));
-					$this->level->addTile($tile);
-				}
 				return true;
 			}
 		}

src/pocketmine/block/Skull.php

@@ -70,14 +70,11 @@ class Skull extends Flowable{
 
 	public function writeStateToWorld() : void{
 		parent::writeStateToWorld();
-		$tile = Tile::create(Tile::SKULL, $this->getLevel(), $this->asVector3());
+		/** @var TileSkull $tile */
-		if($tile !== null){
+		$tile = Tile::create(TileSkull::class, $this->getLevel(), $this->asVector3());
-			if($tile instanceof TileSkull){
+		$tile->setRotation($this->rotation);
-				$tile->setRotation($this->rotation);
+		$tile->setType($this->type);
-				$tile->setType($this->type);
+		$this->level->addTile($tile);
-			}
-			$this->level->addTile($tile);
-		}
 	}
 
 	public function getHardness() : float{

src/pocketmine/block/StandingBanner.php

@@ -84,17 +84,16 @@ class StandingBanner extends Transparent{
 			}
 
 			if($ret){
-				$tile = Tile::createFromItem(Tile::BANNER, $this->getLevel(), $this->asVector3(), $item);
+				/** @var TileBanner $tile */
-				if($tile !== null){
+				$tile = Tile::createFromItem(TileBanner::class, $this->getLevel(), $this->asVector3(), $item);
-					if($tile instanceof TileBanner and $item instanceof ItemBanner){
+				if($item instanceof ItemBanner){
-						$tile->setBaseColor($item->getBaseColor());
+					$tile->setBaseColor($item->getBaseColor());
-						if(($patterns = $item->getPatterns()) !== null){
+					if(($patterns = $item->getPatterns()) !== null){
-							$tile->setPatterns($patterns);
+						$tile->setPatterns($patterns);
-						}
 					}
-
-					$this->level->addTile($tile);
 				}
+
+				$this->level->addTile($tile);
 				return true;
 			}
 		}

src/pocketmine/tile/Sign.php

@@ -125,10 +125,6 @@ class Sign extends Spawnable{
 	}
 
 	public function updateCompoundTag(CompoundTag $nbt, Player $player) : bool{
-		if($nbt->getString("id") !== Tile::SIGN){
-			return false;
-		}
-
 		if($nbt->hasTag(self::TAG_TEXT_BLOB, StringTag::class)){
 			$lines = array_pad(explode("\n", $nbt->getString(self::TAG_TEXT_BLOB)), 4, "");
 		}else{

src/pocketmine/tile/Tile.php

@@ -44,24 +44,14 @@ abstract class Tile extends Position{
 	public const TAG_Y = "y";
 	public const TAG_Z = "z";
 
-	public const BANNER = "Banner";
-	public const BED = "Bed";
-	public const BREWING_STAND = "BrewingStand";
-	public const CHEST = "Chest";
-	public const ENCHANT_TABLE = "EnchantTable";
-	public const ENDER_CHEST = "EnderChest";
-	public const FLOWER_POT = "FlowerPot";
-	public const FURNACE = "Furnace";
-	public const ITEM_FRAME = "ItemFrame";
-	public const MOB_SPAWNER = "MobSpawner";
-	public const SIGN = "Sign";
-	public const SKULL = "Skull";
-
 	/** @var string[] classes that extend Tile */
 	private static $knownTiles = [];
 	/** @var string[][] */
 	private static $saveNames = [];
 
+	/** @var string[] base class => overridden class */
+	private static $classMapping = [];
+
 	/** @var string */
 	public $name = "";
 	/** @var bool */
@@ -70,16 +60,16 @@ abstract class Tile extends Position{
 	protected $timings;
 
 	public static function init(){
-		self::registerTile(Banner::class, [self::BANNER, "minecraft:banner"]);
+		self::register(Banner::class, ["Banner", "minecraft:banner"]);
-		self::registerTile(Bed::class, [self::BED, "minecraft:bed"]);
+		self::register(Bed::class, ["Bed", "minecraft:bed"]);
-		self::registerTile(Chest::class, [self::CHEST, "minecraft:chest"]);
+		self::register(Chest::class, ["Chest", "minecraft:chest"]);
-		self::registerTile(EnchantTable::class, [self::ENCHANT_TABLE, "minecraft:enchanting_table"]);
+		self::register(EnchantTable::class, ["EnchantTable", "minecraft:enchanting_table"]);
-		self::registerTile(EnderChest::class, [self::ENDER_CHEST, "minecraft:ender_chest"]);
+		self::register(EnderChest::class, ["EnderChest", "minecraft:ender_chest"]);
-		self::registerTile(FlowerPot::class, [self::FLOWER_POT, "minecraft:flower_pot"]);
+		self::register(FlowerPot::class, ["FlowerPot", "minecraft:flower_pot"]);
-		self::registerTile(Furnace::class, [self::FURNACE, "minecraft:furnace"]);
+		self::register(Furnace::class, ["Furnace", "minecraft:furnace"]);
-		self::registerTile(ItemFrame::class, [self::ITEM_FRAME]); //this is an entity in PC
+		self::register(ItemFrame::class, ["ItemFrame"]); //this is an entity in PC
-		self::registerTile(Sign::class, [self::SIGN, "minecraft:sign"]);
+		self::register(Sign::class, ["Sign", "minecraft:sign"]);
-		self::registerTile(Skull::class, [self::SKULL, "minecraft:skull"]);
+		self::register(Skull::class, ["Skull", "minecraft:skull"]);
 	}
 
 	/**
@@ -90,27 +80,32 @@ abstract class Tile extends Position{
 	 */
 	public static function createFromData(Level $level, CompoundTag $nbt) : ?Tile{
 		$type = $nbt->getString(self::TAG_ID, "", true);
-		if($type === ""){
+		if(!isset(self::$knownTiles[$type])){
 			return null;
 		}
-		$tile = self::create($type, $level, new Vector3($nbt->getInt(self::TAG_X), $nbt->getInt(self::TAG_Y), $nbt->getInt(self::TAG_Z)));
+		$class = self::$knownTiles[$type];
-		if($tile !== null){
+		assert(is_a($class, Tile::class, true));
-			$tile->readSaveData($nbt);
+		/**
-		}
+		 * @var Tile $tile
+		 * @see Tile::__construct()
+		 */
+		$tile = new $class($level, new Vector3($nbt->getInt(self::TAG_X), $nbt->getInt(self::TAG_Y), $nbt->getInt(self::TAG_Z)));
+		$tile->readSaveData($nbt);
 		return $tile;
 	}
 
 	/**
-	 * @param string  $type
+	 * @param string  $baseClass
 	 * @param Level   $level
 	 * @param Vector3 $pos
 	 * @param Item    $item
 	 *
-	 * @return Tile|null
+	 * @return Tile (instanceof $baseClass)
+	 * @throws \InvalidArgumentException if the base class is not a registered tile
 	 */
-	public static function createFromItem(string $type, Level $level, Vector3 $pos, Item $item) : ?Tile{
+	public static function createFromItem(string $baseClass, Level $level, Vector3 $pos, Item $item) : Tile{
-		$tile = self::create($type, $level, $pos);
+		$tile = self::create($baseClass, $level, $pos);
-		if($tile !== null and $item->hasCustomBlockData()){
+		if($item->hasCustomBlockData()){
 			$tile->readSaveData($item->getCustomBlockData());
 		}
 		if($tile instanceof Nameable and $item->hasCustomName()){ //this should take precedence over saved NBT
@@ -120,34 +115,15 @@ abstract class Tile extends Position{
 		return $tile;
 	}
 
-	/**
-	 * @param string  $type
-	 * @param Level   $level
-	 * @param Vector3 $pos
-	 *
-	 * @return Tile|null
-	 */
-	public static function create(string $type, Level $level, Vector3 $pos) : ?Tile{
-		if(isset(self::$knownTiles[$type])){
-			$class = self::$knownTiles[$type];
-			/**
-			 * @var Tile $tile
-			 * @see Tile::__construct()
-			 */
-			$tile = new $class($level, $pos);
-			return $tile;
-		}
-
-		return null;
-	}
-
 	/**
 	 * @param string   $className
 	 * @param string[] $saveNames
 	 */
-	public static function registerTile(string $className, array $saveNames = []) : void{
+	public static function register(string $className, array $saveNames = []) : void{
 		Utils::testValidInstance($className, Tile::class);
 
+		self::$classMapping[$className] = $className;
+
 		$shortName = (new \ReflectionClass($className))->getShortName();
 		if(!in_array($shortName, $saveNames, true)){
 			$saveNames[] = $shortName;
@@ -160,6 +136,44 @@ abstract class Tile extends Position{
 		self::$saveNames[$className] = $saveNames;
 	}
 
+	/**
+	 * @param string $baseClass Already-registered tile class to override
+	 * @param string $newClass Class which extends the base class
+	 *
+	 * @throws \InvalidArgumentException if the base class is not a registered tile
+	 */
+	public static function override(string $baseClass, string $newClass) : void{
+		if(!isset(self::$classMapping[$baseClass])){
+			throw new \InvalidArgumentException("Class $baseClass is not a registered tile");
+		}
+
+		Utils::testValidInstance($newClass, $baseClass);
+		self::$classMapping[$baseClass] = $newClass;
+	}
+
+	/**
+	 * @param string  $baseClass
+	 * @param Level   $level
+	 * @param Vector3 $pos
+	 *
+	 * @return Tile (will be an instanceof $baseClass)
+	 * @throws \InvalidArgumentException if the specified class is not a registered tile
+	 */
+	public static function create(string $baseClass, Level $level, Vector3 $pos) : Tile{
+		if(isset(self::$classMapping[$baseClass])){
+			$class = self::$classMapping[$baseClass];
+			assert(is_a($class, $baseClass, true));
+			/**
+			 * @var Tile $tile
+			 * @see Tile::__construct()
+			 */
+			$tile = new $class($level, $pos);
+			return $tile;
+		}
+
+		throw new \InvalidArgumentException("Class $baseClass is not a registered tile");
+	}
+
 	/**
 	 * Returns the short save name
 	 * @return string