Fix block pick request handler

Author: Kazzuk

server/src/main/java/org/cloudburstmc/server/player/CloudPlayer.java

@@ -238,7 +238,6 @@ public class CloudPlayer extends EntityHuman implements CommandSender, ChunkLoad
     public long lastSkinChange;
 
     @Getter
-    @Setter
     private int selectedHotbarSlot = 0;
 
     public CloudPlayer(BedrockServerSession session, ClientChainData chainData) {
@@ -3291,6 +3290,16 @@ public void sendHeldItemSlot() {
         this.onInventorySlotChange(this.container, this.selectedHotbarSlot);
     }
 
+    public void setSelectedHotbarSlot(int slot) {
+        this.selectedHotbarSlot = slot;
+
+        PlayerHotbarPacket packet = new PlayerHotbarPacket();
+        packet.setSelectedHotbarSlot(slot);
+        packet.setContainerId(ContainerId.INVENTORY);
+        packet.setSelectHotbarSlot(true);
+        this.sendPacket(packet);
+    }
+
     public void sendInventoryContents() {
         this.onInventoryContentsChange(this.container);
     }

server/src/main/java/org/cloudburstmc/server/player/handler/PlayerPacketHandler.java

@@ -767,9 +767,18 @@ public PacketSignal handle(InteractPacket packet) {
 
     @Override
     public PacketSignal handle(BlockPickRequestPacket packet) {
+        if (player.isSpectator()) {
+            log.debug("Got block-pick request from " + player.getName() + " when in spectator mode");
+            return PacketSignal.HANDLED;
+        }
+
         Vector3i pickPos = packet.getBlockPosition();
         Block block = player.getLevel().getBlock(pickPos.getX(), pickPos.getY(), pickPos.getZ());
 
+        if (block.getState().getType() == AIR) {
+            log.debug("Got block-pick request from " + player.getName() + " for air block");
+            return PacketSignal.HANDLED;
+        }
 
         ItemStack serverItem = ItemStack.from(block.getState());
 
@@ -788,11 +797,6 @@ public PacketSignal handle(BlockPickRequestPacket packet) {
         }
 
         PlayerBlockPickEvent pickEvent = new PlayerBlockPickEvent(player, block, serverItem);
-        if (player.isSpectator()) {
-            log.debug("Got block-pick request from " + player.getName() + " when in spectator mode");
-            pickEvent.setCancelled();
-        }
-
         player.getServer().getEventManager().fire(pickEvent);
 
         if (!pickEvent.isCancelled()) {