Send decorated pot sherds to LAN guests

Decorated pots showed no sherds for LAN guests. A pot is not a block entity here, so the hub and the chunk encoder read the saved tag for it and send the sherds, loot table and item (DecoratedPotBlockEntity.getUpdateTag, saveCustomOnly). Inserting into a pot marks it for update, and a client stores a pot update with the chunk.

crates/horizon-client/src/game/decorated_pot.rs

@@ -131,6 +131,8 @@ impl Game<'_> {
             map.insert("item".into(), save::item_to_nbt(item));
         }
         spill::put_saved_entity(&mut self.world, pos, tag);
+        // The sherds and item go to the guests (BlockEntityData).
+        self.mark_block_entity_updated((pos[0], pos[1], pos[2]));
         self.consume_held();
         self.audio.play(
             "minecraft:block.decorated_pot.insert",

crates/horizon-client/src/game/remote.rs

@@ -1148,6 +1148,23 @@ impl Game<'_> {
         else {
             return;
         };
+        // A decorated pot is no block entity here: its tag is kept with the chunk.
+        if name == "minecraft:decorated_pot" {
+            if let Tag::Compound(fields) = tag
+                && !fields.is_empty()
+            {
+                let mut full = fields.clone();
+                full.insert("id".into(), Tag::String(name.into()));
+                for (k, v) in ["x", "y", "z"].into_iter().zip(pos) {
+                    full.insert(k.into(), Tag::Int(v));
+                }
+                super::spill::put_saved_entity(&mut self.world, pos, Tag::Compound(full));
+                // The section is drawn again with the pot's sherds.
+                let state = self.world.block(pos[0], pos[1], pos[2]);
+                let _ = self.world.set(pos[0], pos[1], pos[2], state);
+            }
+            return;
+        }
         let Some(entity) = self.world.block_entities.get(&key) else {
             return;
         };

crates/horizon-client/src/lan/chunks.rs

@@ -824,6 +824,7 @@ impl ChunkEncoder {
                     tag: block_entities
                         .get(&pos)
                         .and_then(entity_tag)
+                        .or_else(|| pot_tag(chunk, pos))
                         .unwrap_or(Tag::End),
                 });
             }
@@ -984,6 +985,22 @@ pub fn entity_tag(entity: &BlockEntity) -> Option<Tag> {
     }
 }
 
+/// The update tag of the decorated pot at `pos` (DecoratedPotBlockEntity.getUpdateTag,
+/// saveCustomOnly). A pot is not a block entity here: its tag is the chunk's saved one.
+pub fn pot_tag(chunk: &Chunk, pos: (i32, i32, i32)) -> Option<Tag> {
+    let at = chunk.saved.as_ref()?.block_entities.iter().find(|t| {
+        t.get("id") == Some(&Tag::String("minecraft:decorated_pot".into()))
+            && t.get("x") == Some(&Tag::Int(pos.0))
+            && t.get("y") == Some(&Tag::Int(pos.1))
+            && t.get("z") == Some(&Tag::Int(pos.2))
+    })?;
+    let entries: Vec<_> = ["sherds", "LootTable", "LootTableSeed", "item"]
+        .into_iter()
+        .filter_map(|k| Some((k, at.get(k)?.clone())))
+        .collect();
+    (!entries.is_empty()).then(|| Tag::compound(entries))
+}
+
 /// Light sections run from one below the world to one above it. A layer
 /// exists where vanilla's light storage keeps one: within one section of a
 /// non-air section of this column or a neighbouring one (`around`, bit i for

crates/horizon-client/src/lan/hub.rs

@@ -1566,10 +1566,15 @@ impl Hub {
             }
             // Block entities with data the client shows.
             for &(x, y, z) in &positions {
-                let Some(entity) = world.block_entities.get(&(x, y, z)) else {
-                    continue;
+                // A decorated pot is no block entity: its tag is the chunk's saved one.
+                let tag = match world.block_entities.get(&(x, y, z)) {
+                    Some(entity) => super::chunks::entity_tag(entity),
+                    None => world
+                        .chunks
+                        .get(&(x >> 4, z >> 4))
+                        .and_then(|c| super::chunks::pot_tag(c, (x, y, z))),
                 };
-                let Some(tag) = super::chunks::entity_tag(entity) else {
+                let Some(tag) = tag else {
                     continue;
                 };
                 let state = world.block(x, y, z).0;