feat: Add BlockDropResourcesEvent

paper-api/src/main/java/io/papermc/paper/event/block/BlockDropResourcesEvent.java

@@ -0,0 +1,97 @@
+package io.papermc.paper.event.block;
+
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockState;
+import org.bukkit.entity.Entity;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.block.BlockEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import java.util.List;
+
+/**
+    Called when a block is about to drop items
+
+ <p>
+    This event will be called once for every block broken, even if multiple blocks are broken simultaneously.
+    For example, this event will be called twice when breaking a block with a torch on top.
+ </p>
+ <p>
+    This event will also be called when a block is dropping items as a result of being consumed, for example a cake dropping its candle after being eaten.
+ </p>
+ <p>
+    If you do not need the drops of each individual block, use {@link org.bukkit.event.block.BlockBreakEvent}.
+ </p>
+ */
+public class BlockDropResourcesEvent extends BlockEvent implements Cancellable {
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+    private boolean cancelled;
+    private final List<ItemStack> drops;
+    private final Entity breaker;
+    private final ItemStack tool;
+    private final BlockState state;
+
+    @ApiStatus.Internal
+    public BlockDropResourcesEvent(final @NotNull Block block, final @NotNull BlockState state, final @NotNull List<ItemStack> drops, final @Nullable Entity breaker, final @Nullable ItemStack tool) {
+        super(block);
+        this.cancelled = false;
+        this.drops = drops;
+        this.breaker = breaker;
+        this.tool = tool;
+        this.state = state;
+    }
+
+    /**
+     * Get the entity that caused the block to drop resources
+     * @return The responsible entity, or null if no entity was involved
+     */
+    public @Nullable Entity getEntity() {
+        return breaker;
+    }
+
+    /**
+     * Get the tool used to break the block
+     * @return The tool used, or null
+     */
+    public @Nullable ItemStack getTool() {
+        return tool;
+    }
+
+    /**
+     * Get the list of items to be dropped
+     *
+     * @return A mutable list of items to be dropped
+     */
+    public @NotNull List<ItemStack> getItems() {
+        return drops;
+    }
+
+    /**
+     * Get the block state of the block that is about to drop resources
+     * @return The block state
+     */
+    public @NotNull BlockState getBlockState() {
+        return state;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(final boolean cancel) {
+        cancelled = cancel;
+    }
+
+    @Override
+    public @NotNull HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+    public @NotNull static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}

paper-server/patches/sources/net/minecraft/world/level/block/Block.java.patch

@@ -58,7 +58,7 @@
      private @Nullable Item item;
      private static final int CACHE_SIZE = 256;
      private static final ThreadLocal<Object2ByteLinkedOpenHashMap<Block.ShapePairKey>> OCCLUSION_CACHE = ThreadLocal.withInitial(() -> {
-@@ -382,6 +_,27 @@
+@@ -382,19 +_,46 @@
          return state.getDrops(params);
      }
 
@@ -85,29 +85,38 @@
 +
      public static void dropResources(final BlockState state, final Level level, final BlockPos pos) {
          if (level instanceof ServerLevel serverLevel) {
-             getDrops(state, serverLevel, pos, null).forEach(stack -> popResource(level, pos, stack));
-@@ -396,6 +_,12 @@
+-            getDrops(state, serverLevel, pos, null).forEach(stack -> popResource(level, pos, stack));
++            org.bukkit.craftbukkit.event.CraftEventFactory.callBlockDropResourcesEvent(getDrops(state, serverLevel, pos, null), level, pos, state, null, null).forEach(stack -> popResource(level, pos, stack)); // Paper - implement BlockDropResourcesEvent
+             state.spawnAfterBreak(serverLevel, pos, ItemStack.EMPTY, true);
          }
      }
 
+     public static void dropResources(final BlockState state, final LevelAccessor level, final BlockPos pos, final @Nullable BlockEntity blockEntity) {
+         if (level instanceof ServerLevel serverLevel) {
+-            getDrops(state, serverLevel, pos, blockEntity).forEach(stack -> popResource(serverLevel, pos, stack));
++            org.bukkit.craftbukkit.event.CraftEventFactory.callBlockDropResourcesEvent(getDrops(state, serverLevel, pos, blockEntity), level, pos, state, null, null).forEach(stack -> popResource(serverLevel, pos, stack));  // Paper - implement BlockDropResourcesEvent
+             state.spawnAfterBreak(serverLevel, pos, ItemStack.EMPTY, true);
+         }
+     }
++
 +    // Paper start - Properly handle xp dropping
 +    public static void dropResources(final BlockState state, final Level level, final BlockPos pos, final @Nullable BlockEntity blockEntity, final @Nullable Entity breaker, final ItemStack tool) {
 +        dropResources(state, level, pos, blockEntity, breaker, tool, true);
 +    }
 +    // Paper end - Properly handle xp dropping
-+
+ 
      public static void dropResources(
          final BlockState state,
-         final Level level,
 @@ -403,10 +_,11 @@
          final @Nullable BlockEntity blockEntity,
          final @Nullable Entity breaker,
          final ItemStack tool
 +        , final boolean dropExperience // Paper - Properly handle xp dropping
      ) {
          if (level instanceof ServerLevel serverLevel) {
-             getDrops(state, serverLevel, pos, blockEntity, breaker, tool).forEach(stack -> popResource(level, pos, stack));
+-            getDrops(state, serverLevel, pos, blockEntity, breaker, tool).forEach(stack -> popResource(level, pos, stack));
 -            state.spawnAfterBreak(serverLevel, pos, tool, true);
++            org.bukkit.craftbukkit.event.CraftEventFactory.callBlockDropResourcesEvent(getDrops(state, serverLevel, pos, blockEntity, breaker, tool), level, pos, state, breaker, tool).forEach(stack -> popResource(level, pos, stack)); // Paper - implement BlockDropResourcesEvent
 +            state.spawnAfterBreak(serverLevel, pos, tool, dropExperience); // Paper - Properly handle xp dropping
          }
      }

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -9,6 +9,7 @@
 import io.papermc.paper.block.bed.BedEnterProblem;
 import io.papermc.paper.connection.HorriblePlayerLoginEventHack;
 import io.papermc.paper.connection.PlayerConnection;
+import io.papermc.paper.event.block.BlockDropResourcesEvent;
 import io.papermc.paper.event.block.BlockLockCheckEvent;
 import io.papermc.paper.event.connection.PlayerConnectionValidateLoginEvent;
 import io.papermc.paper.event.entity.EntityIgniteEvent;
@@ -2425,4 +2426,31 @@ public static int callEntityIgniteEvent(Entity entity, int fuseTime) {
         }
         return event.getFuseTime();
     }
+
+    public static List<ItemStack> callBlockDropResourcesEvent(List<ItemStack> drops, LevelAccessor level, BlockPos pos, net.minecraft.world.level.block.state.BlockState state, @Nullable Entity breaker, @Nullable ItemStack tool) {
+        if (BlockDropResourcesEvent.getHandlerList().getRegisteredListeners().length == 0) {
+            return drops; // No listeners, skip event creation
+        }
+
+        var converted = new ArrayList<org.bukkit.inventory.ItemStack>();
+        for (var drop : drops) {
+            converted.add(CraftItemStack.asCraftMirror(drop));
+        }
+
+        var stateSnapshot = CraftBlockStates.getBlockState(level, pos);
+        stateSnapshot.setBlock(state);
+
+        var event = new BlockDropResourcesEvent(
+            CraftBlock.at(level, pos),
+            stateSnapshot,
+            converted, breaker == null ? null : breaker.getBukkitEntity(),
+            tool == null ? null : CraftItemStack.asCraftMirror(tool)
+        );
+        if (event.callEvent()) {
+            // convert items back
+            return event.getItems().stream().map(CraftItemStack::asNMSCopy).toList();
+        }
+
+        return List.of(); // return nothing if event was cancelled
+    }
 }