Paper/nms-patches/BlockComposter.patch

--- a/net/minecraft/server/BlockComposter.java
+++ b/net/minecraft/server/BlockComposter.java
@@ -4,13 +4,17 @@
 import it.unimi.dsi.fastutil.objects.Object2FloatOpenHashMap;
 import java.util.Random;
 import javax.annotation.Nullable;
+// CraftBukkit start
+import org.bukkit.craftbukkit.inventory.CraftBlockInventoryHolder;
+import org.bukkit.craftbukkit.util.DummyGeneratorAccess;
+// CraftBukkit end
 
 public class BlockComposter extends Block implements IInventoryHolder {
 
     public static final BlockStateInteger a = BlockProperties.as;
     public static final Object2FloatMap<IMaterial> b = new Object2FloatOpenHashMap();
     private static final VoxelShape c = VoxelShapes.b();
-    private static final VoxelShape[] d = (VoxelShape[]) SystemUtils.a((Object) (new VoxelShape[9]), (avoxelshape) -> {
+    private static final VoxelShape[] d = (VoxelShape[]) SystemUtils.a((new VoxelShape[9]), (avoxelshape) -> { // CraftBukkit - decompile error
         for (int i = 0; i < 8; ++i) {
             avoxelshape[i] = VoxelShapes.a(BlockComposter.c, Block.a(2.0D, (double) Math.max(2, 1 + i * 2), 2.0D, 14.0D, 16.0D, 14.0D), OperatorBoolean.ONLY_FIRST);
         }
@@ -156,18 +160,25 @@
 
             return EnumInteractionResult.a(world.isClientSide);
         } else if (i == 8) {
-            d(iblockdata, world, blockposition);
+            d(iblockdata, world, blockposition, (Entity) null); // CraftBukkit - no event for players
             return EnumInteractionResult.a(world.isClientSide);
         } else {
             return EnumInteractionResult.PASS;
         }
     }
 
-    public static IBlockData a(IBlockData iblockdata, WorldServer worldserver, ItemStack itemstack, BlockPosition blockposition) {
+    public static IBlockData a(IBlockData iblockdata, WorldServer worldserver, ItemStack itemstack, BlockPosition blockposition, Entity entity) { // CraftBukkit
         int i = (Integer) iblockdata.get(BlockComposter.a);
 
         if (i < 7 && BlockComposter.b.containsKey(itemstack.getItem())) {
-            IBlockData iblockdata1 = b(iblockdata, (GeneratorAccess) worldserver, blockposition, itemstack);
+            // CraftBukkit start
+            double rand = worldserver.getRandom().nextDouble();
+            IBlockData iblockdata1 = b(iblockdata, DummyGeneratorAccess.INSTANCE, blockposition, itemstack, rand);
+            if (iblockdata == iblockdata1 || org.bukkit.craftbukkit.event.CraftEventFactory.callEntityChangeBlockEvent(entity, blockposition, iblockdata1).isCancelled()) {
+                return iblockdata;
+            }
+            iblockdata1 = b(iblockdata, (GeneratorAccess) worldserver, blockposition, itemstack, rand);
+            // CraftBukkit end
 
             itemstack.subtract(1);
             return iblockdata1;
@@ -176,7 +187,15 @@
         }
     }
 
-    public static IBlockData d(IBlockData iblockdata, World world, BlockPosition blockposition) {
+    // CraftBukkit start
+    public static IBlockData d(IBlockData iblockdata, World world, BlockPosition blockposition, Entity entity) {
+        if (entity != null) {
+            IBlockData iblockdata1 = d(iblockdata, DummyGeneratorAccess.INSTANCE, blockposition);
+            if (org.bukkit.craftbukkit.event.CraftEventFactory.callEntityChangeBlockEvent(entity, blockposition, iblockdata1).isCancelled()) {
+                return iblockdata;
+            }
+        }
+        // CraftBukkit end
         if (!world.isClientSide) {
             float f = 0.7F;
             double d0 = (double) (world.random.nextFloat() * 0.7F) + 0.15000000596046448D;
@@ -202,10 +221,16 @@
     }
 
     private static IBlockData b(IBlockData iblockdata, GeneratorAccess generatoraccess, BlockPosition blockposition, ItemStack itemstack) {
+        // CraftBukkit start
+        return b(iblockdata, generatoraccess, blockposition, itemstack, generatoraccess.getRandom().nextDouble());
+    }
+
+    private static IBlockData b(IBlockData iblockdata, GeneratorAccess generatoraccess, BlockPosition blockposition, ItemStack itemstack, double rand) {
+        // CraftBukkit end
         int i = (Integer) iblockdata.get(BlockComposter.a);
         float f = BlockComposter.b.getFloat(itemstack.getItem());
 
-        if ((i != 0 || f <= 0.0F) && generatoraccess.getRandom().nextDouble() >= (double) f) {
+        if ((i != 0 || f <= 0.0F) && rand >= (double) f) {
             return iblockdata;
         } else {
             int j = i + 1;
@@ -253,7 +278,8 @@
     public IWorldInventory a(IBlockData iblockdata, GeneratorAccess generatoraccess, BlockPosition blockposition) {
         int i = (Integer) iblockdata.get(BlockComposter.a);
 
-        return (IWorldInventory) (i == 8 ? new BlockComposter.ContainerOutput(iblockdata, generatoraccess, blockposition, new ItemStack(Items.BONE_MEAL)) : (i < 7 ? new BlockComposter.ContainerInput(iblockdata, generatoraccess, blockposition) : new BlockComposter.ContainerEmpty()));
+        // CraftBukkit - empty generatoraccess, blockposition
+        return (IWorldInventory) (i == 8 ? new BlockComposter.ContainerOutput(iblockdata, generatoraccess, blockposition, new ItemStack(Items.BONE_MEAL)) : (i < 7 ? new BlockComposter.ContainerInput(iblockdata, generatoraccess, blockposition) : new BlockComposter.ContainerEmpty(generatoraccess, blockposition)));
     }
 
     static class ContainerInput extends InventorySubcontainer implements IWorldInventory {
@@ -265,6 +291,7 @@
 
         public ContainerInput(IBlockData iblockdata, GeneratorAccess generatoraccess, BlockPosition blockposition) {
             super(1);
+            this.bukkitOwner = new CraftBlockInventoryHolder(generatoraccess, blockposition, this); // CraftBukkit
             this.a = iblockdata;
             this.b = generatoraccess;
             this.c = blockposition;
@@ -317,6 +344,7 @@
             this.blockData = iblockdata;
             this.generatorAccess = generatoraccess;
             this.blockPosition = blockposition;
+            this.bukkitOwner = new CraftBlockInventoryHolder(generatoraccess, blockposition, this); // CraftBukkit
         }
 
         @Override
@@ -341,15 +369,23 @@
 
         @Override
         public void update() {
-            BlockComposter.d(this.blockData, this.generatorAccess, this.blockPosition);
-            this.emptied = true;
+            // CraftBukkit start - allow putting items back (eg cancelled InventoryMoveItemEvent)
+            if (this.isEmpty()) {
+                BlockComposter.d(this.blockData, this.generatorAccess, this.blockPosition);
+                this.emptied = true;
+            } else {
+                this.generatorAccess.setTypeAndData(this.blockPosition, this.blockData, 3);
+                this.emptied = false;
+            }
+            // CraftBukkit end
         }
     }
 
     static class ContainerEmpty extends InventorySubcontainer implements IWorldInventory {
 
-        public ContainerEmpty() {
+        public ContainerEmpty(GeneratorAccess generatoraccess, BlockPosition blockposition) { // CraftBukkit
             super(0);
+            this.bukkitOwner = new CraftBlockInventoryHolder(generatoraccess, blockposition, this); // CraftBukkit
         }
 
         @Override