World: verify saveability of blocks, entities and tiles at entry points

I want to do the same for items, but items are going to be a pain in the ass.
For items there are multiple possible entry points and all of them will need to be checked:
- dropped items
- inventory contents
- lecterns
- item frames

I don't see a good way to deal with all these. We can't check for registration in the constructor
because we need to fully construct the item in order to register it.

Blocks are also a potential issue in other areas, but setBlock() is definitely the biggest offender.

src/block/tile/TileFactory.php

@@ -114,6 +114,13 @@ final class TileFactory{
 		$this->saveNames[$className] = reset($saveNames);
 	}
 
+	/**
+	 * @phpstan-param class-string<Tile> $class
+	 */
+	public function isRegistered(string $class) : bool{
+		return isset($this->saveNames[$class]);
+	}
+
 	/**
 	 * @internal
 	 * @throws SavedDataLoadingException

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

@@ -225,6 +225,10 @@ final class BlockObjectToStateSerializer implements BlockStateSerializer{
 		return $this->cache[$stateId] ??= $this->serializeBlock(RuntimeBlockStateRegistry::getInstance()->fromStateId($stateId));
 	}
 
+	public function isRegistered(Block $block) : bool{
+		return isset($this->serializers[$block->getTypeId()]);
+	}
+
 	/**
 	 * @phpstan-template TBlockType of Block
 	 * @phpstan-param TBlockType $block

src/entity/EntityFactory.php

@@ -219,6 +219,13 @@ final class EntityFactory{
 		$this->saveNames[$className] = reset($saveNames);
 	}
 
+	/**
+	 * @phpstan-param class-string<Entity> $class
+	 */
+	public function isRegistered(string $class) : bool{
+		return isset($this->saveNames[$class]);
+	}
+
 	/**
 	 * Creates an entity from data stored on a chunk.
 	 *

src/world/World.php

@@ -2047,6 +2047,15 @@ class World implements ChunkManager{
 			throw new WorldException("Cannot set a block in un-generated terrain");
 		}
 
+		//TODO: this computes state ID twice (we do it again in writeStateToWorld()). Not great for performance :(
+		$stateId = $block->getStateId();
+		if(!$this->blockStateRegistry->hasStateId($stateId)){
+			throw new \LogicException("Block state ID not known to RuntimeBlockStateRegistry (probably not registered)");
+		}
+		if(!GlobalBlockStateHandlers::getSerializer()->isRegistered($block)){
+			throw new \LogicException("Block not registered with GlobalBlockStateHandlers serializer");
+		}
+
 		$this->timings->setBlock->startTiming();
 
 		$this->unlockChunk($chunkX, $chunkZ, null);
@@ -2769,6 +2778,11 @@ class World implements ChunkManager{
 				throw new AssumptionFailedError("Found two different entities sharing entity ID " . $entity->getId());
 			}
 		}
+		if(!EntityFactory::getInstance()->isRegistered($entity::class)){
+			//canSaveWithChunk is mutable, so that means it could be toggled after adding the entity and cause a crash
+			//later on. Better we just force all entities to have a save ID, even if it might not be needed.
+			throw new \LogicException("Entity " . $entity::class . " is not registered for a save ID in EntityFactory");
+		}
 		$pos = $entity->getPosition()->asVector3();
 		$this->entitiesByChunk[World::chunkHash($pos->getFloorX() >> Chunk::COORD_BIT_SIZE, $pos->getFloorZ() >> Chunk::COORD_BIT_SIZE)][$entity->getId()] = $entity;
 		$this->entityLastKnownPositions[$entity->getId()] = $pos;
@@ -2870,6 +2884,9 @@ class World implements ChunkManager{
 		if(!$this->isInWorld($pos->getFloorX(), $pos->getFloorY(), $pos->getFloorZ())){
 			throw new \InvalidArgumentException("Tile position is outside the world bounds");
 		}
+		if(!TileFactory::getInstance()->isRegistered($tile::class)){
+			throw new \LogicException("Tile " . $tile::class . " is not registered for a save ID in TileFactory");
+		}
 
 		$chunkX = $pos->getFloorX() >> Chunk::COORD_BIT_SIZE;
 		$chunkZ = $pos->getFloorZ() >> Chunk::COORD_BIT_SIZE;