handle nil nbt

crates/core/item/src/edcode.rs

@@ -6,7 +6,7 @@ use crate::{stack::ItemStackCx, ItemStack, RawItem};
 
 impl<Cx> Encode for ItemStack<'_, Cx>
 where
-    Cx: ItemStackCx + for<'a> WriteNbt<&'a Cx::Compound>,
+    Cx: ItemStackCx + for<'a> WriteNbt<Option<&'a Cx::Compound>>,
 {
     fn encode<B>(&self, mut buf: B) -> Result<(), std::io::Error>
     where
@@ -20,12 +20,7 @@ where
             item.encode(&mut buf)?;
             self.count().encode(&mut buf)?;
             if item.settings().max_damage.is_some() || item.settings().sync_nbt {
-                if let Some(x) = self.nbt() {
-                    Cx::write_nbt(x, buf.writer())?
-                } else {
-                    // @TODO: Write empty nbt tag.
-                    todo!()
-                }
+                Cx::write_nbt(self.nbt(), buf.writer())?
             }
         }
         Ok(())
@@ -34,7 +29,7 @@ where
 
 impl<'r, Cx> Decode for ItemStack<'r, Cx>
 where
-    Cx: ItemStackCx + for<'a> ReadNbt<&'a Cx::Compound> + ProvideRegistry<'r, Cx::Id, RawItem<Cx>>,
+    Cx: ItemStackCx + ReadNbt<Option<Cx::Compound>> + ProvideRegistry<'r, Cx::Id, RawItem<Cx>>,
 {
     fn decode<B>(mut buf: B) -> Result<Self, std::io::Error>
     where
@@ -43,9 +38,8 @@ where
         if bool::decode(&mut buf)? {
             let item = Reg::<'r, Cx::Id, RawItem<Cx>>::decode(&mut buf)?;
             let count = u8::decode(&mut buf)?;
-            // @TODO: Handle null tags.
-            let nbt = todo!();
-            // Ok(ItemStack::with_nbt(item, count, nbt))
+            let nbt = Cx::read_nbt(buf.reader())?;
+            Ok(ItemStack::with_nbt(item, count, nbt))
         } else {
             Ok(ItemStack::empty())
         }