Clean up confusing mess around block and item overriding

right now, I don't see an obvious reason to do this. If it turns out I was wrong later on, we can add functionality back, but we can't remove functionality after release.

src/block/RuntimeBlockStateRegistry.php

@@ -81,22 +81,16 @@ class RuntimeBlockStateRegistry{
 	}
 
 	/**
-	 * Maps a block type to its corresponding type ID. This is necessary for the block to be recognized when loading
-	 * from disk, and also when being read at runtime.
+	 * Maps a block type's state permutations to its corresponding state IDs. This is necessary for the block to be
+	 * recognized when fetching it by its state ID from chunks at runtime.
 	 *
-	 * NOTE: If you are registering a new block type, you will need to add it to the creative inventory yourself - it
-	 * will not automatically appear there.
-	 *
-	 * @param bool $override Whether to override existing registrations
-	 *
-	 * @throws \InvalidArgumentException if something attempted to override an already-registered block without specifying the
-	 * $override parameter.
+	 * @throws \InvalidArgumentException if the desired block type ID is already registered
 	 */
-	public function register(Block $block, bool $override = false) : void{
+	public function register(Block $block) : void{
 		$typeId = $block->getTypeId();
 
-		if(!$override && isset($this->typeIndex[$typeId])){
-			throw new \InvalidArgumentException("Block ID $typeId is already used by another block, and override was not requested");
+		if(isset($this->typeIndex[$typeId])){
+			throw new \InvalidArgumentException("Block ID $typeId is already used by another block");
 		}
 
 		$this->typeIndex[$typeId] = clone $block;

src/data/bedrock/block/convert/BlockObjectToStateSerializer.php

@@ -210,8 +210,7 @@ final class BlockObjectToStateSerializer implements BlockStateSerializer{
 	 */
 	public function map(Block $block, \Closure $serializer) : void{
 		if(isset($this->serializers[$block->getTypeId()])){
-			//TODO: REMOVE ME
-			throw new AssumptionFailedError("Registering the same block twice!");
+			throw new \InvalidArgumentException("Block type ID " . $block->getTypeId() . " already has a serializer registered");
 		}
 		$this->serializers[$block->getTypeId()][get_class($block)] = $serializer;
 	}

src/data/bedrock/item/ItemDeserializer.php

@@ -51,6 +51,9 @@ final class ItemDeserializer{
 	 * @phpstan-param \Closure(Data) : Item $deserializer
 	 */
 	public function map(string $id, \Closure $deserializer) : void{
+		if(isset($this->deserializers[$id])){
+			throw new \InvalidArgumentException("Deserializer is already assigned for \"$id\"");
+		}
 		$this->deserializers[$id] = $deserializer;
 	}
 

src/data/bedrock/item/ItemSerializer.php

@@ -67,8 +67,7 @@ final class ItemSerializer{
 	public function map(Item $item, \Closure $serializer) : void{
 		$index = $item->getTypeId();
 		if(isset($this->itemSerializers[$index])){
-			//TODO: REMOVE ME
-			throw new AssumptionFailedError("Registering the same item twice!");
+			throw new \InvalidArgumentException("Item type ID " . $index . " already has a serializer registered");
 		}
 		$this->itemSerializers[$index][get_class($item)] = $serializer;
 	}

tests/phpunit/block/BlockTest.php

@@ -49,15 +49,6 @@ class BlockTest extends TestCase{
 		$this->blockFactory->register($block);
 	}
 
-	/**
-	 * Test registering a block deliberately overwriting another block works as expected
-	 */
-	public function testDeliberateOverrideBlock() : void{
-		$block = new MyCustomBlock(new BlockIdentifier(BlockTypeIds::COBBLESTONE), "Cobblestone", new BlockTypeInfo(BlockBreakInfo::instant()));
-		$this->blockFactory->register($block, true);
-		self::assertInstanceOf(MyCustomBlock::class, $this->blockFactory->fromStateId($block->getStateId()));
-	}
-
 	/**
 	 * Test registering a new block which does not yet exist
 	 */