From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Wed, 6 Oct 2021 20:50:48 -0700
Subject: [PATCH] Fix upstreams block state factories

Sometimes, blocks are changed and then logic is called before the associated
tile entity is removed. When this happens, the factories were relying on the
block at the position, not the tile entity. This change prioritizes using the
tile entity type to determine the block state factory and falls back on
the material type of the block at that location.

diff --git a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
index 0e37da7227eaba0d089e5bd136eca088ab2b5eb3..5601d0c2fe635a2a4f073c333531e1a8adf1833c 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
@@ -270,7 +270,7 @@ public abstract class BlockEntity implements io.papermc.paper.util.KeyedObject {
         // Paper end
         if (this.level == null) return null;
         org.bukkit.block.Block block = this.level.getWorld().getBlockAt(this.worldPosition.getX(), this.worldPosition.getY(), this.worldPosition.getZ());
-        if (block.getType() == org.bukkit.Material.AIR) return null;
+        // if (block.getType() == org.bukkit.Material.AIR) return null; // Paper - actually get the tile entity if it still exists
         org.bukkit.block.BlockState state = block.getState(useSnapshot); // Paper
         if (state instanceof InventoryHolder) return (InventoryHolder) state;
         return null;
diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
index d46e3812ef058c119d327cf752e7deaa341736e3..8c847183a398df386ae5a24467378c5c3b889dc7 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
@@ -6,7 +6,7 @@ import org.bukkit.World;
 import org.bukkit.block.TileState;
 import org.bukkit.persistence.PersistentDataContainer;
 
-public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockState implements TileState {
+public abstract class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockState implements TileState { // Paper - revert upstream's revert of the block state changes
 
     private final T tileEntity;
     private final T snapshot;
diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
index 93a8aeb5545c794ac425c35f8af52a443cd060ca..9a4d79973af25853c4173a1df0131830505b623b 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
@@ -19,6 +19,7 @@ import net.minecraft.world.level.block.entity.BeehiveBlockEntity;
 import net.minecraft.world.level.block.entity.BellBlockEntity;
 import net.minecraft.world.level.block.entity.BlastFurnaceBlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.BlockEntityType; // Paper
 import net.minecraft.world.level.block.entity.BrewingStandBlockEntity;
 import net.minecraft.world.level.block.entity.CampfireBlockEntity;
 import net.minecraft.world.level.block.entity.ChestBlockEntity;
@@ -105,188 +106,55 @@ public final class CraftBlockStates {
     private static final BlockStateFactory<?> DEFAULT_FACTORY = new BlockStateFactory<CraftBlockState>(CraftBlockState.class) {
         @Override
         public CraftBlockState createBlockState(World world, BlockPos blockPosition, net.minecraft.world.level.block.state.BlockState blockData, BlockEntity tileEntity) {
-            // SPIGOT-6754, SPIGOT-6817: Restore previous behaviour for tile entities with removed blocks (loot generation post-destroy)
-            if (tileEntity != null) {
-                // block with unhandled TileEntity:
-                return new CraftBlockEntityState<>(world, tileEntity);
-            }
+            // Paper - revert upstream's revert of the block state changes. Block entities that have already had the block type set to AIR are still valid, upstream decided to ignore them
             Preconditions.checkState(tileEntity == null, "Unexpected BlockState for %s", CraftMagicNumbers.getMaterial(blockData.getBlock()));
             return new CraftBlockState(world, blockPosition, blockData);
         }
     };
+    // Paper start
+    private static final Map<BlockEntityType<?>, BlockStateFactory<?>> FACTORIES_BY_BLOCK_ENTITY_TYPE = new HashMap<>();
+    private static void register(BlockEntityType<?> type, BlockStateFactory<?> factory) {
+        FACTORIES_BY_BLOCK_ENTITY_TYPE.put(type, factory);
+    }
+    // Paper end
 
     static {
-        register(
-                Arrays.asList(
-                        Material.ACACIA_SIGN,
-                        Material.ACACIA_WALL_SIGN,
-                        Material.BIRCH_SIGN,
-                        Material.BIRCH_WALL_SIGN,
-                        Material.CRIMSON_SIGN,
-                        Material.CRIMSON_WALL_SIGN,
-                        Material.DARK_OAK_SIGN,
-                        Material.DARK_OAK_WALL_SIGN,
-                        Material.JUNGLE_SIGN,
-                        Material.JUNGLE_WALL_SIGN,
-                        Material.OAK_SIGN,
-                        Material.OAK_WALL_SIGN,
-                        Material.SPRUCE_SIGN,
-                        Material.SPRUCE_WALL_SIGN,
-                        Material.WARPED_SIGN,
-                        Material.WARPED_WALL_SIGN
-                ), CraftSign.class, CraftSign::new, SignBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.CREEPER_HEAD,
-                        Material.CREEPER_WALL_HEAD,
-                        Material.DRAGON_HEAD,
-                        Material.DRAGON_WALL_HEAD,
-                        Material.PLAYER_HEAD,
-                        Material.PLAYER_WALL_HEAD,
-                        Material.SKELETON_SKULL,
-                        Material.SKELETON_WALL_SKULL,
-                        Material.WITHER_SKELETON_SKULL,
-                        Material.WITHER_SKELETON_WALL_SKULL,
-                        Material.ZOMBIE_HEAD,
-                        Material.ZOMBIE_WALL_HEAD
-                ), CraftSkull.class, CraftSkull::new, SkullBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.COMMAND_BLOCK,
-                        Material.REPEATING_COMMAND_BLOCK,
-                        Material.CHAIN_COMMAND_BLOCK
-                ), CraftCommandBlock.class, CraftCommandBlock::new, CommandBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.BLACK_BANNER,
-                        Material.BLACK_WALL_BANNER,
-                        Material.BLUE_BANNER,
-                        Material.BLUE_WALL_BANNER,
-                        Material.BROWN_BANNER,
-                        Material.BROWN_WALL_BANNER,
-                        Material.CYAN_BANNER,
-                        Material.CYAN_WALL_BANNER,
-                        Material.GRAY_BANNER,
-                        Material.GRAY_WALL_BANNER,
-                        Material.GREEN_BANNER,
-                        Material.GREEN_WALL_BANNER,
-                        Material.LIGHT_BLUE_BANNER,
-                        Material.LIGHT_BLUE_WALL_BANNER,
-                        Material.LIGHT_GRAY_BANNER,
-                        Material.LIGHT_GRAY_WALL_BANNER,
-                        Material.LIME_BANNER,
-                        Material.LIME_WALL_BANNER,
-                        Material.MAGENTA_BANNER,
-                        Material.MAGENTA_WALL_BANNER,
-                        Material.ORANGE_BANNER,
-                        Material.ORANGE_WALL_BANNER,
-                        Material.PINK_BANNER,
-                        Material.PINK_WALL_BANNER,
-                        Material.PURPLE_BANNER,
-                        Material.PURPLE_WALL_BANNER,
-                        Material.RED_BANNER,
-                        Material.RED_WALL_BANNER,
-                        Material.WHITE_BANNER,
-                        Material.WHITE_WALL_BANNER,
-                        Material.YELLOW_BANNER,
-                        Material.YELLOW_WALL_BANNER
-                ), CraftBanner.class, CraftBanner::new, BannerBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.SHULKER_BOX,
-                        Material.WHITE_SHULKER_BOX,
-                        Material.ORANGE_SHULKER_BOX,
-                        Material.MAGENTA_SHULKER_BOX,
-                        Material.LIGHT_BLUE_SHULKER_BOX,
-                        Material.YELLOW_SHULKER_BOX,
-                        Material.LIME_SHULKER_BOX,
-                        Material.PINK_SHULKER_BOX,
-                        Material.GRAY_SHULKER_BOX,
-                        Material.LIGHT_GRAY_SHULKER_BOX,
-                        Material.CYAN_SHULKER_BOX,
-                        Material.PURPLE_SHULKER_BOX,
-                        Material.BLUE_SHULKER_BOX,
-                        Material.BROWN_SHULKER_BOX,
-                        Material.GREEN_SHULKER_BOX,
-                        Material.RED_SHULKER_BOX,
-                        Material.BLACK_SHULKER_BOX
-                ), CraftShulkerBox.class, CraftShulkerBox::new, ShulkerBoxBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.BLACK_BED,
-                        Material.BLUE_BED,
-                        Material.BROWN_BED,
-                        Material.CYAN_BED,
-                        Material.GRAY_BED,
-                        Material.GREEN_BED,
-                        Material.LIGHT_BLUE_BED,
-                        Material.LIGHT_GRAY_BED,
-                        Material.LIME_BED,
-                        Material.MAGENTA_BED,
-                        Material.ORANGE_BED,
-                        Material.PINK_BED,
-                        Material.PURPLE_BED,
-                        Material.RED_BED,
-                        Material.WHITE_BED,
-                        Material.YELLOW_BED
-                ), CraftBed.class, CraftBed::new, BedBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.BEEHIVE,
-                        Material.BEE_NEST
-                ), CraftBeehive.class, CraftBeehive::new, BeehiveBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.CAMPFIRE,
-                        Material.SOUL_CAMPFIRE
-                ), CraftCampfire.class, CraftCampfire::new, CampfireBlockEntity::new
-        );
-
-        register(
-                Arrays.asList(
-                        Material.CHEST,
-                        Material.TRAPPED_CHEST
-                ), CraftChest.class, CraftChest::new, ChestBlockEntity::new
-        );
-
-        register(Material.BARREL, CraftBarrel.class, CraftBarrel::new, BarrelBlockEntity::new);
-        register(Material.BEACON, CraftBeacon.class, CraftBeacon::new, BeaconBlockEntity::new);
-        register(Material.BELL, CraftBell.class, CraftBell::new, BellBlockEntity::new);
-        register(Material.BLAST_FURNACE, CraftBlastFurnace.class, CraftBlastFurnace::new, BlastFurnaceBlockEntity::new);
-        register(Material.BREWING_STAND, CraftBrewingStand.class, CraftBrewingStand::new, BrewingStandBlockEntity::new);
-        register(Material.COMPARATOR, CraftComparator.class, CraftComparator::new, ComparatorBlockEntity::new);
-        register(Material.CONDUIT, CraftConduit.class, CraftConduit::new, ConduitBlockEntity::new);
-        register(Material.DAYLIGHT_DETECTOR, CraftDaylightDetector.class, CraftDaylightDetector::new, DaylightDetectorBlockEntity::new);
-        register(Material.DISPENSER, CraftDispenser.class, CraftDispenser::new, DispenserBlockEntity::new);
-        register(Material.DROPPER, CraftDropper.class, CraftDropper::new, DropperBlockEntity::new);
-        register(Material.ENCHANTING_TABLE, CraftEnchantingTable.class, CraftEnchantingTable::new, EnchantmentTableBlockEntity::new);
-        register(Material.ENDER_CHEST, CraftEnderChest.class, CraftEnderChest::new, EnderChestBlockEntity::new);
-        register(Material.END_GATEWAY, CraftEndGateway.class, CraftEndGateway::new, TheEndGatewayBlockEntity::new);
-        register(Material.END_PORTAL, CraftEndPortal.class, CraftEndPortal::new, TheEndPortalBlockEntity::new);
-        register(Material.FURNACE, CraftFurnaceFurnace.class, CraftFurnaceFurnace::new, FurnaceBlockEntity::new);
-        register(Material.HOPPER, CraftHopper.class, CraftHopper::new, HopperBlockEntity::new);
-        register(Material.JIGSAW, CraftJigsaw.class, CraftJigsaw::new, JigsawBlockEntity::new);
-        register(Material.JUKEBOX, CraftJukebox.class, CraftJukebox::new, JukeboxBlockEntity::new);
-        register(Material.LECTERN, CraftLectern.class, CraftLectern::new, LecternBlockEntity::new);
-        register(Material.MOVING_PISTON, CraftMovingPiston.class, CraftMovingPiston::new, PistonMovingBlockEntity::new);
-        register(Material.SCULK_SENSOR, CraftSculkSensor.class, CraftSculkSensor::new, SculkSensorBlockEntity::new);
-        register(Material.SMOKER, CraftSmoker.class, CraftSmoker::new, SmokerBlockEntity::new);
-        register(Material.SPAWNER, CraftCreatureSpawner.class, CraftCreatureSpawner::new, SpawnerBlockEntity::new);
-        register(Material.STRUCTURE_BLOCK, CraftStructureBlock.class, CraftStructureBlock::new, StructureBlockEntity::new);
+        // Paper start - simplify
+        register(BlockEntityType.SIGN, CraftSign.class, CraftSign::new);
+        register(BlockEntityType.SKULL, CraftSkull.class, CraftSkull::new);
+        register(BlockEntityType.COMMAND_BLOCK, CraftCommandBlock.class, CraftCommandBlock::new);
+        register(BlockEntityType.BANNER, CraftBanner.class, CraftBanner::new);
+        register(BlockEntityType.SHULKER_BOX, CraftShulkerBox.class, CraftShulkerBox::new);
+        register(BlockEntityType.BED, CraftBed.class, CraftBed::new);
+        register(BlockEntityType.BEEHIVE, CraftBeehive.class, CraftBeehive::new);
+        register(BlockEntityType.CAMPFIRE, CraftCampfire.class, CraftCampfire::new);
+        register(BlockEntityType.CHEST, CraftChest.class, CraftChest::new); // Paper - split up chests due to different block entity types
+        register(BlockEntityType.TRAPPED_CHEST, CraftChest.class, CraftChest::new); // Paper - split up chests due to different block entity types
+        register(BlockEntityType.BARREL, CraftBarrel.class, CraftBarrel::new);
+        register(BlockEntityType.BEACON, CraftBeacon.class, CraftBeacon::new);
+        register(BlockEntityType.BELL, CraftBell.class, CraftBell::new);
+        register(BlockEntityType.BLAST_FURNACE, CraftBlastFurnace.class, CraftBlastFurnace::new);
+        register(BlockEntityType.BREWING_STAND, CraftBrewingStand.class, CraftBrewingStand::new);
+        register(BlockEntityType.COMPARATOR, CraftComparator.class, CraftComparator::new);
+        register(BlockEntityType.CONDUIT, CraftConduit.class, CraftConduit::new);
+        register(BlockEntityType.DAYLIGHT_DETECTOR, CraftDaylightDetector.class, CraftDaylightDetector::new);
+        register(BlockEntityType.DISPENSER, CraftDispenser.class, CraftDispenser::new);
+        register(BlockEntityType.DROPPER, CraftDropper.class, CraftDropper::new);
+        register(BlockEntityType.ENCHANTING_TABLE, CraftEnchantingTable.class, CraftEnchantingTable::new);
+        register(BlockEntityType.ENDER_CHEST, CraftEnderChest.class, CraftEnderChest::new);
+        register(BlockEntityType.END_GATEWAY, CraftEndGateway.class, CraftEndGateway::new);
+        register(BlockEntityType.END_PORTAL, CraftEndPortal.class, CraftEndPortal::new);
+        register(BlockEntityType.FURNACE, CraftFurnaceFurnace.class, CraftFurnaceFurnace::new);
+        register(BlockEntityType.HOPPER, CraftHopper.class, CraftHopper::new);
+        register(BlockEntityType.JIGSAW, CraftJigsaw.class, CraftJigsaw::new);
+        register(BlockEntityType.JUKEBOX, CraftJukebox.class, CraftJukebox::new);
+        register(BlockEntityType.LECTERN, CraftLectern.class, CraftLectern::new);
+        register(BlockEntityType.PISTON, CraftMovingPiston.class, CraftMovingPiston::new);
+        register(BlockEntityType.SCULK_SENSOR, CraftSculkSensor.class, CraftSculkSensor::new);
+        register(BlockEntityType.SMOKER, CraftSmoker.class, CraftSmoker::new);
+        register(BlockEntityType.MOB_SPAWNER, CraftCreatureSpawner.class, CraftCreatureSpawner::new);
+        register(BlockEntityType.STRUCTURE_BLOCK, CraftStructureBlock.class, CraftStructureBlock::new);
+        // Paper end
     }
 
     private static void register(Material blockType, BlockStateFactory<?> factory) {
@@ -294,35 +162,45 @@ public final class CraftBlockStates {
     }
 
     private static <T extends BlockEntity, B extends CraftBlockEntityState<T>> void register(
-            Material blockType,
+            net.minecraft.world.level.block.entity.BlockEntityType<? extends T> blockEntityType, // Paper
             Class<B> blockStateType,
-            BiFunction<World, T, B> blockStateConstructor,
-            BiFunction<BlockPos, net.minecraft.world.level.block.state.BlockState, T> tileEntityConstructor
+            BiFunction<World, T, B> blockStateConstructor // Paper
     ) {
-        CraftBlockStates.register(Collections.singletonList(blockType), blockStateType, blockStateConstructor, tileEntityConstructor);
-    }
-
-    private static <T extends BlockEntity, B extends CraftBlockEntityState<T>> void register(
-            List<Material> blockTypes,
-            Class<B> blockStateType,
-            BiFunction<World, T, B> blockStateConstructor,
-            BiFunction<BlockPos, net.minecraft.world.level.block.state.BlockState, T> tileEntityConstructor
-    ) {
-        BlockStateFactory<B> factory = new BlockEntityStateFactory<>(blockStateType, blockStateConstructor, tileEntityConstructor);
-        for (Material blockType : blockTypes) {
-            CraftBlockStates.register(blockType, factory);
+        // Paper start
+        BlockStateFactory<B> factory = new BlockEntityStateFactory<>(blockStateType, blockStateConstructor, blockEntityType::create);
+        for (net.minecraft.world.level.block.Block block : blockEntityType.validBlocks) {
+            CraftBlockStates.register(CraftMagicNumbers.getMaterial(block), factory);
         }
+        CraftBlockStates.register(blockEntityType, factory);
+        // Paper end
     }
 
     private static BlockStateFactory<?> getFactory(Material material) {
         return CraftBlockStates.FACTORIES.getOrDefault(material, DEFAULT_FACTORY);
     }
 
+    // Paper start
+    private static BlockStateFactory<?> getFactory(Material material, BlockEntityType<?> type) {
+        if (type != null) {
+            return CraftBlockStates.FACTORIES_BY_BLOCK_ENTITY_TYPE.getOrDefault(type, getFactory(material));
+        } else {
+            return getFactory(material);
+        }
+    }
+    // Paper end
+
     public static Class<? extends CraftBlockState> getBlockStateType(Material material) {
         Preconditions.checkNotNull(material, "material is null");
         return CraftBlockStates.getFactory(material).blockStateType;
     }
 
+    // Paper start
+    public static Class<? extends CraftBlockState> getBlockStateType(BlockEntityType<?> blockEntityType) {
+        Preconditions.checkNotNull(blockEntityType, "blockEntityType is null");
+        return CraftBlockStates.getFactory(null, blockEntityType).blockStateType;
+    }
+    // Paper end
+
     public static BlockState getBlockState(Block block) {
         // Paper start
         return CraftBlockStates.getBlockState(block, true);
@@ -380,7 +258,7 @@ public final class CraftBlockStates {
         if (world != null && tileEntity == null && CraftBlockStates.isTileEntityOptional(material)) {
             factory = CraftBlockStates.DEFAULT_FACTORY;
         } else {
-            factory = CraftBlockStates.getFactory(material);
+            factory = CraftBlockStates.getFactory(material, tileEntity != null ? tileEntity.getType() : null); // Paper
         }
         return factory.createBlockState(world, blockPosition, blockData, tileEntity);
     }
diff --git a/src/test/java/org/bukkit/craftbukkit/block/BlockStateTest.java b/src/test/java/org/bukkit/craftbukkit/block/BlockStateTest.java
index 738227d8dbab8460d2bd7f75098e91bcae2d1ff3..8980163dabdd21d040bc7e622e9a22d01f73005b 100644
--- a/src/test/java/org/bukkit/craftbukkit/block/BlockStateTest.java
+++ b/src/test/java/org/bukkit/craftbukkit/block/BlockStateTest.java
@@ -26,4 +26,11 @@ public class BlockStateTest extends AbstractTestingBase {
             }
         }
     }
+
+    @Test
+    public void testBlockEntityTypes() {
+        for (var blockEntityType : Registry.BLOCK_ENTITY_TYPE) {
+            org.junit.Assert.assertNotNull(CraftBlockStates.getBlockStateType(blockEntityType));
+        }
+    }
 }
