From a6439e39a7dfa83dea738465da1ab79cd4fdab52 Mon Sep 17 00:00:00 2001
From: MagmaMac <xmachd@gmail.com>
Date: Thu, 21 Sep 2023 22:12:52 +1000
Subject: [PATCH] Solve inability for items with improper NBT data to be moved
 out of inventories (#529)

Hi,
# Objective

I was playing around with the chest example.
After adding an item with NBT data, I noticed I was unable to remove it
from the chest.
Sourced the error down to this check. All I have done is not check the
NBT data for now.

Same as in last comment of #292 .

# Solution

Only item kind and count checked, nbt ignored.

Kind Regards,
Mac

---------

Co-authored-by: Carson McManus <dyc3@users.noreply.github.com>
---
 crates/valence_inventory/src/validate.rs | 42 +++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/crates/valence_inventory/src/validate.rs b/crates/valence_inventory/src/validate.rs
index 4cee7f4ed..086b85cd2 100644
--- a/crates/valence_inventory/src/validate.rs
+++ b/crates/valence_inventory/src/validate.rs
@@ -167,7 +167,10 @@ pub(super) fn validate_click_slot_packet(
                 if should_swap {
                     // assert that a swap occurs
                     ensure!(
-                        *old_slot == packet.carried_item
+                        // There are some cases where the client will add NBT data that
+                        // did not previously exist.
+                        old_slot.item == packet.carried_item.item
+                            && old_slot.count == packet.carried_item.count
                             && cursor_item.0 == packet.slot_changes[0].stack,
                         "swapped items must match"
                     );
@@ -355,6 +358,8 @@ fn calculate_net_item_delta(
 
 #[cfg(test)]
 mod tests {
+    use valence_server::nbt::Compound;
+    use valence_server::nbt::Value::Int;
     use valence_server::protocol::packets::play::click_slot_c2s::SlotChange;
     use valence_server::protocol::VarInt;
     use valence_server::{ItemKind, ItemStack};
@@ -464,6 +469,41 @@ mod tests {
             .expect("packet should be valid");
     }
 
+    #[test]
+    fn click_filled_slot_with_incorrect_nbt_and_empty_cursor_success() {
+        let player_inventory = Inventory::new(InventoryKind::Player);
+        let cursor_item = CursorItem(ItemStack::EMPTY);
+
+        let mut inventory = Inventory::new(InventoryKind::Generic9x1);
+        // Insert an item with no NBT data that should have NBT Data.
+        inventory.set_slot(0, ItemStack::new(ItemKind::DiamondPickaxe, 1, None));
+
+        // Proper NBT Compound
+        let mut compound = Compound::new();
+        compound.insert("Damage", Int(1));
+
+        let packet = ClickSlotC2s {
+            window_id: 1,
+            state_id: VarInt(0),
+            slot_idx: 0,
+            button: 0,
+            mode: ClickMode::Click,
+            slot_changes: vec![SlotChange {
+                idx: 0,
+                stack: ItemStack::EMPTY,
+            }]
+            .into(),
+            carried_item: ItemStack {
+                item: ItemKind::DiamondPickaxe,
+                count: 1,
+                nbt: Some(compound),
+            },
+        };
+
+        validate_click_slot_packet(&packet, &player_inventory, Some(&inventory), &cursor_item)
+            .expect("packet should be valid");
+    }
+
     #[test]
     fn click_slot_with_filled_cursor_success() {
         let player_inventory = Inventory::new(InventoryKind::Player);