Allow adding items to BlockDropItemEvent

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

@@ -461,14 +461,31 @@ public class CraftEventFactory {
     }
 
     public static void handleBlockDropItemEvent(Block block, BlockState state, ServerPlayer player, List<ItemEntity> items) {
-        BlockDropItemEvent event = new BlockDropItemEvent(block, state, player.getBukkitEntity(), Lists.transform(items, (item) -> (org.bukkit.entity.Item) item.getBukkitEntity()));
+        // Paper start - Allow adding items to BlockDropItemEvent
+        List<Item> list = new ArrayList<>();
+        for (ItemEntity item : items) {
+            list.add((Item) item.getBukkitEntity());
+        }
+        BlockDropItemEvent event = new BlockDropItemEvent(block, state, player.getBukkitEntity(), list);
+        // Paper end - Allow adding items to BlockDropItemEvent
         Bukkit.getPluginManager().callEvent(event);
 
         if (!event.isCancelled()) {
-            for (ItemEntity item : items) {
+            // Paper start - Allow adding items to BlockDropItemEvent
+            for (Item bukkit : list) {
+                if (!bukkit.isValid()) {
+                    Entity item = ((org.bukkit.craftbukkit.entity.CraftItem) bukkit).getHandle();
                     item.level().addFreshEntity(item);
                 }
             }
+        } else {
+            for (Item bukkit : list) {
+                if (bukkit.isValid()) {
+                    bukkit.remove();
+                }
+            }
+            // Paper end - Allow adding items to BlockDropItemEvent
+        }
     }
 
     public static EntityPlaceEvent callEntityPlaceEvent(UseOnContext itemactioncontext, Entity entity) {