Merge upstream main into item expiry hooks

crates/horizon-client-render/src/audio.rs

@@ -1206,8 +1206,13 @@ impl Audio {
     /// `SoundManager.reload` (resource packs changed): stop every sound, then
     /// read sound events and sound files from the new resource root.
     pub fn reload(&mut self, root: &Path) {
+        self.reload_with(root, SoundRegistry::load(root));
+    }
+    /// [`Self::reload`] with the root's sound events already read
+    /// (`SoundRegistry::load`, which a pack reload runs off the render thread).
+    pub fn reload_with(&mut self, root: &Path, registry: SoundRegistry) {
         self.stop_all();
-        self.engine.registry = SoundRegistry::load(root);
+        self.engine.registry = registry;
         self.backend.root = root.to_owned();
         let mut cache = self.backend.cache.lock().unwrap();
         cache.entries.clear();

crates/horizon-client-render/src/collisions.rs

@@ -182,12 +182,24 @@ where
         movement: Vec3,
         max_step: f32,
         on_ground: bool,
+    ) -> Result<Vec3> {
+        let context = CollisionContext::position(bounds.min_position().y);
+        self.resolve_with_context(bounds, movement, max_step, on_ground, context)
+    }
+    /// [`Self::resolve`] with the entity's captured collision context.
+    pub fn resolve_with_context(
+        &mut self,
+        bounds: Aabb,
+        movement: Vec3,
+        max_step: f32,
+        on_ground: bool,
+        context: CollisionContext<'_>,
     ) -> Result<Vec3> {
         Ok(resolve_world_movement(
             self,
             MovementRequest {
                 entity: EntityIdentity(0),
-                context: CollisionContext::position(bounds.min_position().y),
+                context,
                 bounds,
                 movement,
                 max_step,
@@ -223,23 +235,12 @@ impl SceneCollisions<'_, '_> {
         border: Option<(&BorderGeometry, [f64; 2])>,
     ) -> Result<Vec3> {
         let context = self.context(bounds);
-        let mut scene = EntityCollisions {
+        EntityCollisions {
             blocks: self,
             entities: &[],
             border,
-        };
-        Ok(resolve_world_movement(
-            &mut scene,
-            MovementRequest {
-                entity: EntityIdentity(0),
-                context,
-                bounds,
-                movement,
-                max_step,
-                on_ground,
-                candidate_budget: 1_000_000,
-            },
-        )?)
+        }
+        .resolve_with_context(bounds, movement, max_step, on_ground, context)
     }
     /// Resolve movement with the entity's captured collision context. Most
     /// callers only need the position context; entities such as falling blocks

crates/horizon-client-render/src/ui.rs

@@ -50,6 +50,18 @@ fn parse_nine_slice(v: &serde_json::Value) -> Option<NineSlice> {
 }
 /// Read `gui.scaling` metadata for every GUI sprite under `root`.
 pub fn load_metadata(root: &Path) {
+    set_metadata(read_metadata(root));
+}
+/// The GUI sprites' nine-slice metadata of a resource root, read off the
+/// render thread by a pack reload ([`read_metadata`]) and put in use with
+/// [`set_metadata`].
+pub struct UiMetadata(HashMap<String, NineSlice>);
+/// Puts read metadata in use ([`load_metadata`] in two halves).
+pub fn set_metadata(metadata: UiMetadata) {
+    *NINE_SLICE.write().unwrap_or_else(|e| e.into_inner()) = Some(metadata.0);
+}
+/// Reads the metadata [`load_metadata`] puts in use, without putting it in use.
+pub fn read_metadata(root: &Path) -> UiMetadata {
     let mut map = HashMap::new();
     let base = root.join("assets/minecraft/textures");
     let mut stack = vec![base.join("gui/sprites")];
@@ -84,7 +96,7 @@ pub fn load_metadata(root: &Path) {
             map.insert(key, nine_slice);
         }
     }
-    *NINE_SLICE.write().unwrap_or_else(|e| e.into_inner()) = Some(map);
+    UiMetadata(map)
 }
 /// The sprite's nine-slice metadata, when its `.png.mcmeta` has any.
 fn nine_slice_metadata(sprite: &str) -> Option<NineSlice> {

crates/horizon-client/src/entities.rs

@@ -12,7 +12,7 @@ use crate::{
     world::World,
 };
 use horizon_core::{
-    geometry::{Aabb, Direction, Vec3, VoxelShape},
+    geometry::{Aabb, Direction, Vec3, VoxelShape, border::BorderGeometry},
     position::BlockPos,
 };
 use horizon_world::{
@@ -261,6 +261,7 @@ impl ItemEntity {
         no_physics: bool,
         fluids: &crate::motion::FluidResources,
         entity_boxes: &[Aabb],
+        border: Option<&BorderGeometry>,
     ) -> bool {
         self.ticks += 1;
         self.previous = self.position;
@@ -295,7 +296,7 @@ impl ItemEntity {
             || horizontal > 1.0e-5
             || self.ticks.wrapping_add(self.id).is_multiple_of(4)
         {
-            let mut scene = SceneCollisions {
+            let scene = SceneCollisions {
                 world,
                 binding: collision,
                 subject: None,
@@ -311,17 +312,14 @@ impl ItemEntity {
             // Entity.move with noPhysics: straight through, the ground as it was.
             let moved = if no_physics {
                 wanted
-            } else if entity_boxes.is_empty() {
-                scene
-                    .resolve(self.bounds(), wanted, 0.0, self.on_ground)
-                    .unwrap_or(Vec3::ZERO)
             } else {
                 // `Entity.collide`: the entities that `canBeCollidedWith` the item stop it
-                // too (a boat, a minecart, a shulker, a happy ghast held still).
+                // too (a boat, a minecart, a shulker, a happy ghast held still), and
+                // so does the world border (`Entity.collectColliders`).
                 crate::collisions::EntityCollisions {
                     blocks: scene,
                     entities: entity_boxes,
-                    border: None,
+                    border: border.map(|b| (b, [self.position.x, self.position.z])),
                 }
                 .resolve(self.bounds(), wanted, 0.0, self.on_ground)
                 .unwrap_or(Vec3::ZERO)
@@ -860,6 +858,7 @@ impl ExperienceOrb {
         player: Option<[f64; 3]>,
         server: bool,
         next_float: &mut dyn FnMut() -> f32,
+        border: Option<&BorderGeometry>,
     ) -> bool {
         self.ticks += 1;
         self.previous = self.position;
@@ -924,8 +923,10 @@ impl ExperienceOrb {
         // `double fallSpeed = getDeltaMovement().y`, taken after the stuck
         // push and before the move.
         let wanted = self.velocity;
+        // Entity.collide: the world border's walls stop the orb too.
+        let border = border.map(|b| (b, [self.position.x, self.position.z]));
         let moved = scene
-            .resolve(bounds, wanted, 0.0, self.on_ground)
+            .resolve_in_border(bounds, wanted, 0.0, self.on_ground, border)
             .unwrap_or(Vec3::ZERO);
         self.position = Vec3::new(
             self.position.x + moved.x,
@@ -1962,6 +1963,73 @@ mod merge_tests {
     }
 }
 
+#[cfg(test)]
+mod world_border_tests {
+    use super::*;
+
+    /// `Entity.collectColliders` (#7080): the world border's wall stops an
+    /// item and an experience orb as it stops the player. A border of size
+    /// 10 around (20, 20) has its east wall at x = 25; each body starts at
+    /// x = 24 on the flat ground of the test scene, moving 1.5 east.
+    #[test]
+    fn the_world_border_stops_items_and_experience_orbs() {
+        let root = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("../../.local/horizon-client")
+            .join(horizon_core::VANILLA_VERSION);
+        if !root.join("movement-properties.nbt").exists() {
+            return;
+        }
+        let assets = crate::assets::Assets::load(&root).unwrap();
+        let render = assets.reload(&root).unwrap();
+        let facts = crate::blocks::BlockFacts::load(&root, assets.registry).unwrap();
+        let fluids = crate::motion::FluidResources::new(&assets, &facts).unwrap();
+        let collision = crate::collisions::load(&root, assets.registry).unwrap();
+        let world = World::test_scene(&assets, &render, 3).unwrap();
+        let border = BorderGeometry::new([20.0, 20.0], 10.0, 29_999_984).unwrap();
+        for bordered in [false, true] {
+            let border = bordered.then_some(&border);
+            let mut item = super::honey_slide_tests::falling_item(24.0, 4.0, 20.5, 1.5, 0.0, 0.0);
+            item.tick(
+                &world,
+                assets.registry,
+                &facts,
+                &collision,
+                false,
+                &fluids,
+                &[],
+                border,
+            );
+            let mut orb = ExperienceOrb {
+                no_gravity: false,
+                id: 2,
+                position: Vec3::new(24.0, 4.0, 20.5),
+                previous: Vec3::new(24.0, 4.0, 20.5),
+                velocity: Vec3::new(1.5, 0.0, 0.0),
+                value: 1,
+                age: 0,
+                on_ground: true,
+                count: 1,
+                ticks: 0,
+                health: 5,
+            };
+            orb.tick(&world, &facts, &collision, None, true, &mut || 0.0, border);
+            for (what, east) in [
+                ("item", item.bounds().max_position().x),
+                ("orb", orb.bounds().max_position().x),
+            ] {
+                if bordered {
+                    assert!(
+                        (east - 25.0).abs() < 1.0e-7,
+                        "the {what} stops on the wall at x = 25, got {east}"
+                    );
+                } else {
+                    assert!(east > 25.0, "no border: the {what} goes on, got {east}");
+                }
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod honey_slide_tests {
     use super::*;
@@ -2004,6 +2072,7 @@ mod honey_slide_tests {
                 false,
                 &fluids,
                 &[],
+                None,
             );
             ys.push(item.velocity.y);
         }
@@ -2068,6 +2137,7 @@ mod honey_slide_tests {
                 false,
                 &fluids,
                 &[],
+                None,
             );
         }
         assert!(
@@ -2364,6 +2434,7 @@ mod slime_bounce_tests {
             false,
             &fluids,
             &[],
+            None,
         );
         assert_eq!(falling.position.y, 4.0);
         assert!(falling.velocity.y > 0.0);
@@ -2382,6 +2453,7 @@ mod slime_bounce_tests {
             false,
             &fluids,
             &[],
+            None,
         );
         assert!(!falling.needs_sync);
     }
@@ -2474,6 +2546,7 @@ mod entity_collision_tests {
                     false,
                     &fluids,
                     boxes,
+                    None,
                 );
             }
             item.position.y
@@ -2522,6 +2595,7 @@ mod entity_collision_tests {
                     false,
                     &fluids,
                     &[],
+                    None,
                 );
             }
             item.position.x

crates/horizon-client/src/entities/fluids.rs

@@ -262,7 +262,8 @@ mod tests {
             &collision,
             false,
             &fluids,
-            &[]
+            &[],
+            None
         ));
         assert_eq!(still.position.x, at.x);
         assert_eq!(still.velocity.x, 0.0);
@@ -275,7 +276,8 @@ mod tests {
             &collision,
             false,
             &fluids,
-            &[]
+            &[],
+            None
         ));
         // First push is damped by buoyancy before motion, second follows drag.
         assert!((carried.position.x - at.x - 0.014 * 0.99).abs() < 1e-12);
@@ -289,6 +291,7 @@ mod tests {
                 false,
                 &fluids,
                 &[],
+                None,
             );
         }
         assert!(carried.position.x > at.x + 0.5);

crates/horizon-client/src/entity_nbt.rs

@@ -677,10 +677,10 @@ pub fn mob_to_nbt(
         | "minecraft:trader_llama" => {
             map.insert("Tame".into(), Tag::Byte(i8::from(m.extra.tame)));
             map.insert("Temper".into(), Tag::Int(i32::from(m.extra.variant3)));
-            // AbstractHorse.addAdditionalSaveData; Horizon models neither.
-            for key in ["EatingHaystack", "Bred"] {
-                map.entry(key.into()).or_insert(Tag::Byte(0));
-            }
+            map.insert("Bred".into(), Tag::Byte(i8::from(m.extra.bred)));
+            // AbstractHorse.addAdditionalSaveData; Horizon does not model the
+            // eating haystack yet.
+            map.entry("EatingHaystack".into()).or_insert(Tag::Byte(0));
             if let Some(owner) = m.extra.owner {
                 map.insert("Owner".into(), Tag::IntArray(owner.to_vec()));
             }
@@ -1608,6 +1608,7 @@ pub fn mob_from_nbt(
     if crate::mobs::equine::is_equine(m.species()) {
         m.extra.tame = flag(tag, "Tame");
         m.extra.variant3 = number(tag.get("Temper")).unwrap_or(0).clamp(0, 100) as u8;
+        m.extra.bred = flag(tag, "Bred");
         m.extra.owner = crate::save::uuid_from_tag(tag.get("Owner"));
         let v = number(tag.get("Variant")).unwrap_or(0) as i32;
         m.extra.variant = (v & 0xFF).clamp(0, 6) as u8;
@@ -2414,7 +2415,7 @@ const THROWABLE_ITEMS: [&str; 5] = [
 fn throwable_item(kind: &ProjectileKind) -> Option<&str> {
     match kind {
         ProjectileKind::Thrown(t) => Some(t.item),
-        ProjectileKind::Potion(stack) => Some(&stack.item),
+        ProjectileKind::Potion(stack, _) => Some(&stack.item),
         _ => THROWABLE_ITEMS.iter().find(|id| **id == kind.id()).copied(),
     }
 }
@@ -2430,20 +2431,37 @@ pub fn throwable_kind(id: &str) -> Option<ProjectileKind> {
         "minecraft:snowball" => Some(ProjectileKind::Snowball),
         "minecraft:egg" => Some(ProjectileKind::Egg),
         "minecraft:ender_pearl" => Some(ProjectileKind::EnderPearl),
-        _ => Some(ProjectileKind::Potion(Box::new(
-            crate::items::ItemStack::new(id, 1),
-        ))),
+        // The entity type is the id; the `Item` read later may be another potion.
+        _ => Some(ProjectileKind::Potion(
+            Box::new(crate::items::ItemStack::new(id, 1)),
+            id == "minecraft:lingering_potion",
+        )),
     }
 }
 
 /// Whether its chunk saves it: the kinds `arrow_to_nbt`, `fireball_to_nbt`
 /// and [`throwable_to_nbt`] write.
 pub fn saved_with_chunk(p: &Projectile) -> bool {
-    matches!(
-        p.kind,
-        ProjectileKind::LargeFireball { .. } | ProjectileKind::SmallFireball
-    ) || (p.arrow.is_some() && matches!(p.kind, ProjectileKind::Arrow { .. }))
-        || throwable_item(&p.kind).is_some()
+    // No wildcard: a kind added to `ProjectileKind` must say here whether its
+    // chunk saves it (`Entity.shouldBeSaved` is true for every projectile in
+    // vanilla), and a `true` needs a writer in `entity_chunks`.
+    match &p.kind {
+        ProjectileKind::LargeFireball { .. }
+        | ProjectileKind::SmallFireball
+        | ProjectileKind::WindCharge
+        | ProjectileKind::BreezeWindCharge
+        | ProjectileKind::Snowball
+        | ProjectileKind::Egg
+        | ProjectileKind::EnderPearl
+        | ProjectileKind::Potion(..)
+        | ProjectileKind::Thrown(_) => true,
+        ProjectileKind::Arrow { .. } => p.arrow.is_some(),
+        // Not written yet: tridents save from their own list.
+        ProjectileKind::Trident
+        | ProjectileKind::LlamaSpit
+        | ProjectileKind::ShulkerBullet { .. }
+        | ProjectileKind::WitherSkull { .. } => false,
+    }
 }
 
 /// `ThrowableItemProjectile.addAdditionalSaveData`: `Projectile`'s keys and
@@ -2474,7 +2492,7 @@ pub fn throwable_to_nbt(
     // effects); when there is none, `getItem`'s default is written.
     if tag.get("Item").is_none() {
         let stack = match &p.kind {
-            ProjectileKind::Potion(stack) => (**stack).clone(),
+            ProjectileKind::Potion(stack, _) => (**stack).clone(),
             _ => crate::items::ItemStack::new(item, 1),
         };
         put(&mut tag, "Item", item_to_nbt(&stack));
@@ -2488,7 +2506,7 @@ pub fn throwable_from_nbt(tag: &Tag, player: Option<[i32; 4]>) -> Option<Project
     let mut kind = throwable_kind(&kind(tag)?)?;
     // `readAdditionalSaveData` sets the `Item` it flies as, potion effects
     // and all; a tag without one keeps `getItem`'s default.
-    if let ProjectileKind::Potion(stack) = &mut kind
+    if let ProjectileKind::Potion(stack, _) = &mut kind
         && let Some(item) = tag.get("Item").and_then(item_from_nbt)
     {
         **stack = item;
@@ -2747,12 +2765,25 @@ pub fn painting_to_nbt(p: &Painting, uuid: [i32; 4], raw: Option<&Tag>) -> Tag {
     put(&mut tag, "block_pos", Tag::IntArray(p.pos.to_vec()));
     tag
 }
+/// `BlockAttachedEntity.readAdditionalSaveData`: `block_pos` when saved; a
+/// summoned one has none, and `setPos` puts its block at the block holding
+/// the summon position.
+fn attached_block_pos(tag: &Tag) -> Option<[i32; 3]> {
+    match tag.get("block_pos") {
+        Some(Tag::IntArray(v)) if v.len() == 3 => Some([v[0], v[1], v[2]]),
+        _ => {
+            let at = position(tag)?;
+            Some([
+                at.x.floor() as i32,
+                at.y.floor() as i32,
+                at.z.floor() as i32,
+            ])
+        }
+    }
+}
 /// The block position, facing and variant of a saved painting.
 pub fn painting_from_nbt(tag: &Tag) -> Option<([i32; 3], u8, String)> {
-    let pos = match tag.get("block_pos") {
-        Some(Tag::IntArray(v)) if v.len() == 3 => [v[0], v[1], v[2]],
-        _ => return None,
-    };
+    let pos = attached_block_pos(tag)?;
     let facing = (number(tag.get("facing")).unwrap_or(0) & 3) as u8;
     Some((pos, facing, text(tag.get("variant"))?))
 }
@@ -2865,10 +2896,7 @@ pub fn item_frame_to_nbt(f: &ItemFrame, uuid: [i32; 4], raw: Option<&Tag>) -> Ta
     tag
 }
 pub fn item_frame_from_nbt(tag: &Tag, id: u32) -> Option<ItemFrame> {
-    let pos = match tag.get("block_pos") {
-        Some(Tag::IntArray(v)) if v.len() == 3 => [v[0], v[1], v[2]],
-        _ => return None,
-    };
+    let pos = attached_block_pos(tag)?;
     Some(ItemFrame {
         id,
         pos,
@@ -4904,7 +4932,10 @@ mod fireball_nbt_tests {
             assert_eq!(p.kind.id(), id);
             assert_eq!(
                 p.kind,
-                ProjectileKind::Potion(Box::new(crate::items::ItemStack::new(id, 1)))
+                ProjectileKind::Potion(
+                    Box::new(crate::items::ItemStack::new(id, 1)),
+                    id == "minecraft:lingering_potion"
+                )
             );
             assert!(saved_with_chunk(&p));
             let tag = throwable_to_nbt(&p, [1; 4], None, None).unwrap();
@@ -4926,7 +4957,7 @@ mod fireball_nbt_tests {
             ),
         ]);
         let p = throwable_from_nbt(&harming, None).unwrap();
-        let ProjectileKind::Potion(stack) = &p.kind else {
+        let ProjectileKind::Potion(stack, _) = &p.kind else {
             panic!("a potion");
         };
         assert_eq!(stack.potion(), Some("minecraft:harming"));
@@ -4950,6 +4981,67 @@ mod fireball_nbt_tests {
         assert_eq!(p.kind.id(), "minecraft:lingering_potion");
     }
 
+    #[test]
+    fn wind_charges_in_flight_are_saved_and_read_back() {
+        // vanilla 26.3 saves them (`Entity.shouldBeSaved` is true; the round
+        // trip of a vanilla world lost all four before this).
+        for id in ["minecraft:wind_charge", "minecraft:breeze_wind_charge"] {
+            let saved = Tag::compound([
+                ("id", Tag::String(id.into())),
+                ("Pos", doubles(&[4.5, 80.0, 10.5])),
+                ("NoGravity", Tag::Byte(1)),
+                ("acceleration_power", Tag::Double(0.1_f64.to_bits())),
+            ]);
+            let p = fireball_from_nbt(&saved, None).unwrap();
+            assert_eq!(p.kind.id(), id);
+            assert!(saved_with_chunk(&p), "{id}");
+            let tag = fireball_to_nbt(&p, [1; 4], None, Some(&saved)).unwrap();
+            assert_eq!(kind(&tag).as_deref(), Some(id));
+            assert_eq!(tag.get("NoGravity"), Some(&Tag::Byte(1)));
+        }
+    }
+
+    #[test]
+    fn a_lingering_potion_keeps_its_type_whatever_item_it_flies_as() {
+        // `/summon minecraft:lingering_potion ~ ~ ~ {Item:{id:"minecraft:splash_potion"}}`
+        // is a `ThrownLingeringPotion` in vanilla and stays one when saved.
+        let tag = Tag::compound([
+            ("id", Tag::String("minecraft:lingering_potion".into())),
+            ("Pos", doubles(&[24.5, 80.0, 8.5])),
+            (
+                "Item",
+                item_to_nbt(&crate::items::ItemStack::new("minecraft:splash_potion", 1)),
+            ),
+        ]);
+        let p = throwable_from_nbt(&tag, None).unwrap();
+        assert_eq!(p.kind.id(), "minecraft:lingering_potion");
+        let back = throwable_to_nbt(&p, [1; 4], None, Some(&tag)).unwrap();
+        assert_eq!(kind(&back).as_deref(), Some("minecraft:lingering_potion"));
+        let item = back.get("Item").and_then(item_from_nbt).unwrap();
+        assert_eq!(&*item.item, "minecraft:splash_potion");
+    }
+
+    #[test]
+    fn a_summoned_painting_or_frame_has_no_block_pos_and_sits_at_its_position() {
+        // BlockAttachedEntity.setPos: the block holding the summon position.
+        let painting = Tag::compound([
+            ("id", Tag::String("minecraft:painting".into())),
+            ("Pos", doubles(&[28.5, 80.0, 6.5])),
+            ("variant", Tag::String("minecraft:kebab".into())),
+            ("facing", Tag::Byte(3)),
+        ]);
+        assert_eq!(
+            painting_from_nbt(&painting),
+            Some(([28, 80, 6], 3, "minecraft:kebab".to_string()))
+        );
+        let frame = Tag::compound([
+            ("id", Tag::String("minecraft:item_frame".into())),
+            ("Pos", doubles(&[-0.5, 80.0, 6.5])),
+            ("Facing", Tag::Byte(1)),
+        ]);
+        assert_eq!(item_frame_from_nbt(&frame, 1).unwrap().pos, [-1, 80, 6]);
+    }
+
     #[test]
     fn thrown_item_projectiles_round_trip_their_flight_item_and_owner() {
         let player = Some([5, 6, 7, 8]);
@@ -4983,11 +5075,12 @@ mod fireball_nbt_tests {
             let resaved = throwable_to_nbt(&away, [1; 4], away.owner_uuid, None).unwrap();
             assert_eq!(uuid_from_tag(resaved.get("Owner")), player);
         }
-        // the chunk saves arrows, fireballs and these, and so takes them with it.
+        // the chunk saves arrows, fireballs, wind charges and these, and so takes them with it.
         let kinds = [
             (ProjectileKind::SmallFireball, true),
             (ProjectileKind::Snowball, true),
-            (ProjectileKind::WindCharge, false),
+            (ProjectileKind::WindCharge, true),
+            (ProjectileKind::BreezeWindCharge, true),
             (ProjectileKind::Trident, false),
         ];
         for (kind, saved) in kinds {

crates/horizon-client/src/game.rs

@@ -3828,9 +3828,7 @@ impl Game<'_> {
             stuck: Vec3::ZERO,
         });
         // ServerLevel.addFreshEntity.
-        if !self.native_entity_joins(self.next_entity, "minecraft:item", position, false) {
-            self.dropped.pop();
-        } else {
+        if self.native_joins_flush(false, self.next_entity) {
             self.native_item_spawn(self.next_entity, &item, count, position);
         }
     }
@@ -3943,8 +3941,8 @@ impl Game<'_> {
         // THROW and a creative tab's drop included.
         self.swing_hand(Hand::Main, SwingAnimation::DEFAULT);
         // Player.drop: the drop statistics.
-        self.stats.add("dropped", &thrown.item, thrown.count as i32);
-        self.stats.custom("drop", 1);
+        self.award_stat("dropped", &thrown.item, thrown.count as i32);
+        self.award_custom_stat("drop", 1);
         let player = self.native_acting_id();
         self.native_item_dropped(player, &thrown.item, thrown.count);
         self.throw_from_eyes(thrown, eye, true);
@@ -4059,6 +4057,7 @@ impl Game<'_> {
                 no_physics,
                 &self.res.motion().fluids,
                 &nearby,
+                Some(self.border.geometry()),
             );
             cells.moved(i, item.previous, item.position);
             // Entity.handleOnAboveBubbleColumn: the server sends the particles of
@@ -4179,7 +4178,7 @@ impl Game<'_> {
                 let thrower = item.thrower;
                 match self.give(item.stack.clone()) {
                     None => {
-                        self.stats.add("picked_up", &kind, before as i32);
+                        self.award_stat("picked_up", &kind, before as i32);
                         if let Some(thrower) = thrower {
                             self.trigger_thrown_picked_up_by_player(&item.stack, thrower);
                         }
@@ -4198,8 +4197,7 @@ impl Game<'_> {
                     }
                     Some(rest) => {
                         if rest.count < before {
-                            self.stats
-                                .add("picked_up", &kind, (before - rest.count) as i32);
+                            self.award_stat("picked_up", &kind, (before - rest.count) as i32);
                             if let Some(thrower) = thrower {
                                 self.trigger_thrown_picked_up_by_player(&rest, thrower);
                             }
@@ -4430,7 +4428,7 @@ impl Game<'_> {
         });
         // NoteBlock.attack awards the statistic.
         if note {
-            self.stats.custom("play_noteblock", 1);
+            self.award_custom_stat("play_noteblock", 1);
         }
         self.process_level_events()
     }
@@ -5215,7 +5213,7 @@ impl Game<'_> {
                     PlayerEffect::DropItem(_) => {}
                     PlayerEffect::EatCake => {
                         // CakeBlock.eat
-                        self.stats.custom("eat_cake_slice", 1);
+                        self.award_custom_stat("eat_cake_slice", 1);
                         if let Some(p) = self.player.as_mut() {
                             let food = &mut p.health.food;
                             food.food = (food.food + 2).min(20);
@@ -5430,7 +5428,7 @@ impl Game<'_> {
         } else if &*name == "minecraft:ender_chest" {
             self.open_ender_chest(key);
             // EnderChestBlock.useWithoutItem
-            self.stats.custom("open_enderchest", 1);
+            self.award_custom_stat("open_enderchest", 1);
             self.anger_piglins(true);
             if self.container_opener_event(key, true) {
                 self.container_edge_sound(key, true);
@@ -5469,7 +5467,7 @@ impl Game<'_> {
                 _ => "",
             };
             if !stat.is_empty() {
-                self.stats.custom(stat, 1);
+                self.award_custom_stat(stat, 1);
             }
             // Opening a piglin-guarded container angers the piglins who see it.
             if self.guarded_by_piglins(&name) {
@@ -5546,7 +5544,7 @@ impl Game<'_> {
             f.stuck = Vec3::ZERO;
             f.velocity = Vec3::ZERO;
         }
-        let mut scene = collisions::SceneCollisions {
+        let scene = collisions::SceneCollisions {
             world: &self.world,
             binding: self.collision,
             subject: Some(collisions::PowderSnowSubject {
@@ -5565,7 +5563,13 @@ impl Game<'_> {
             false,
         );
         // On an error the caller keeps the block as it was before this tick.
-        let movement = scene.resolve_with_context(
+        // Entity.collide: the world border's walls stop it too.
+        let movement = collisions::EntityCollisions {
+            blocks: scene,
+            entities: &[],
+            border: Some((self.border.geometry(), [f.position.x, f.position.z])),
+        }
+        .resolve_with_context(
             horizon_client::falling_block::bounds(f.position),
             wanted,
             0.0,
@@ -5750,7 +5754,7 @@ impl Game<'_> {
         if wears && per_block > 0 && max > 0 {
             self.damage_held(per_block);
         }
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
     }
     fn break_block(&mut self, pos: [i32; 3]) -> Result<()> {
         self.lan_break_pos = Some(pos);
@@ -5859,7 +5863,7 @@ impl Game<'_> {
                     .correct_for_drops(held.as_ref(), &facts.name);
             if harvest {
                 // Block.playerDestroy: the mined statistic, the exhaustion and the drops.
-                self.stats.add("mined", &facts.name, 1);
+                self.award_stat("mined", &facts.name, 1);
                 if let Some(p) = self.player.as_mut() {
                     p.cause_food_exhaustion(0.005);
                 }
@@ -6238,7 +6242,7 @@ impl Game<'_> {
                     && result == horizon_world::level::InteractionResult::Success
                     && let Some(used) = held.as_ref()
                 {
-                    self.stats.add("used", &used.item, 1);
+                    self.award_stat("used", &used.item, 1);
                     self.consume_held();
                 }
                 // FlowerPotBlock.useItemOn: the plant is potted, used up, and counted.
@@ -6246,8 +6250,8 @@ impl Game<'_> {
                     && result == horizon_world::level::InteractionResult::Success
                     && let Some(used) = held.as_ref()
                 {
-                    self.stats.add("used", &used.item, 1);
-                    self.stats.custom("pot_flower", 1);
+                    self.award_stat("used", &used.item, 1);
+                    self.award_custom_stat("pot_flower", 1);
                     self.consume_held();
                     if let (Some(player), Some(name)) =
                         (self.lan_acting_uuid, self.lan_acting_name.clone())
@@ -6266,8 +6270,8 @@ impl Game<'_> {
                         .name
                         .clone();
                     match &*name {
-                        "minecraft:note_block" => self.stats.custom("tune_noteblock", 1),
-                        "minecraft:bell" => self.stats.custom("bell_ring", 1),
+                        "minecraft:note_block" => self.award_custom_stat("tune_noteblock", 1),
+                        "minecraft:bell" => self.award_custom_stat("bell_ring", 1),
                         "minecraft:lever" => self.lever_puff(hit.pos),
                         _ => {}
                     }
@@ -6507,7 +6511,7 @@ impl Game<'_> {
             // BlockItem.useOn: a consumable that could not be placed is used,
             // which ItemStack.useOn counts as a use of the item.
             if self.start_eating(&info) {
-                self.stats.add("used", &stack.item, 1);
+                self.award_stat("used", &stack.item, 1);
             } else {
                 // BlockItem.place's FAIL.
                 self.use_failed = true;
@@ -6554,7 +6558,7 @@ impl Game<'_> {
         }
         self.process_level_events()?;
         // BlockItem.place: the used statistic and the placed_block trigger.
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.trigger_block("minecraft:placed_block", target, &stack);
         self.native_place_block(&stack, target, state);
         self.check_wither_spawn(target)?;
@@ -6648,7 +6652,7 @@ impl Game<'_> {
             let group = horizon_client::cooldowns::group(stack, None);
             self.add_cooldown(group, instrument.use_ticks());
         }
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
     }
     fn apply_consume_effect(&mut self, effect: &horizon_client::items::ConsumeEffect) {
         use horizon_client::items::ConsumeEffect;
@@ -6882,7 +6886,7 @@ impl Game<'_> {
             0.8,
             pitch,
         );
-        self.stats.add("used", &item, 1);
+        self.award_stat("used", &item, 1);
     }
     /// `LivingEntity.releaseUsingItem` (`Item.releaseUsing`) for `stack`,
     /// used for `ticks`, its hand acting: a bow or a trident lets go (not
@@ -7285,6 +7289,8 @@ impl Game<'_> {
     /// What the tick runs after the local player's own update: effects, the
     /// world's entities and blocks, and the network hub.
     fn tick_world(&mut self, running: bool) -> Result<()> {
+        // Entities added since the last tick join the level before it ticks.
+        self.native_joins_flush(false, 0);
         self.share_spawn_conditions();
         horizon_client::mobs::sulfur_cube::set_tnt_explodes(self.ui.rules.bool("tnt_explodes"));
         self.update_chunk_tickets();
@@ -10305,7 +10311,7 @@ impl Game<'_> {
                 // (native_item_crafted).
                 let player = self.native_acting_id();
                 self.native_item_crafted(player, &format!("minecraft:{recipe}"), &taken);
-                self.stats.add("crafted", &made.0, made.1 as i32);
+                self.award_stat("crafted", &made.0, made.1 as i32);
                 self.award_crafted(&[(format!("minecraft:{recipe}"), ingredients)]);
                 if !shift || crafted >= 64 {
                     break;
@@ -11373,8 +11379,7 @@ impl Game<'_> {
                 mob.kind.width,
                 mob.kind.height,
             );
-            self.stats
-                .custom("damage_dealt", (actual * 10.0).round() as i32);
+            self.award_custom_stat("damage_dealt", (actual * 10.0).round() as i32);
             if crit {
                 self.critical_hit(
                     self.lan_acting,
@@ -12088,7 +12093,7 @@ impl Game<'_> {
         }
         self.close_container();
         if self.remote.is_none() {
-            self.stats.custom("leave_game", 1);
+            self.award_custom_stat("leave_game", 1);
         }
         self.lan_close(false);
         self.free_player_beds()?;
@@ -12490,7 +12495,7 @@ impl Game<'_> {
             return Ok(false);
         }
         if let Some(stat) = result.stat {
-            self.stats.custom(stat, 1);
+            self.award_custom_stat(stat, 1);
         }
         if let Some(block) = result.block
             && let Ok(new) = registry.resolve(&block)
@@ -12625,7 +12630,7 @@ impl Game<'_> {
             self.audio.play(&sound, Some(at), 1.0, 1.0);
         }
         // ItemStack.useOn: a use that acted counts as one of the item.
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.damage_held(damage);
         self.post_block_game_event("minecraft:block_change", pos, self.sculk_actor(), Some(new));
         Ok(true)
@@ -12722,7 +12727,7 @@ impl Game<'_> {
                 let broken = stack.item.clone();
                 let gone = stack.clone();
                 *cell = None;
-                self.stats.add("broken", &broken, 1);
+                self.award_stat("broken", &broken, 1);
                 // LivingEntity.onEquippedItemBroken: the sound and the crumbs.
                 self.player_equipment_broke(
                     horizon_world::player_inventory::EquipmentSlot::MainHand,
@@ -12813,7 +12818,7 @@ impl Game<'_> {
             self.process_level_events()?;
             // `player.awardStat(Stats.ITEM_USED.get(this))`,
             // `getPickupSound` and `level.gameEvent(player, FLUID_PICKUP)`.
-            self.stats.add("used", "minecraft:bucket", 1);
+            self.award_stat("used", "minecraft:bucket", 1);
             let sound = if filled == "minecraft:lava_bucket" {
                 "minecraft:item.bucket.fill_lava"
             } else {
@@ -12933,7 +12938,7 @@ impl Game<'_> {
                     self.sculk_actor(),
                     Some(state),
                 );
-                self.stats.add("used", &stack.item, 1);
+                self.award_stat("used", &stack.item, 1);
                 if !self.creative {
                     self.consume_held();
                 }
@@ -13134,9 +13139,7 @@ impl Game<'_> {
             health: 5,
         });
         // ServerLevel.addFreshEntity.
-        if !self.native_entity_joins(self.next_entity, "minecraft:experience_orb", at, false) {
-            self.orbs.pop();
-        }
+        self.native_joins_flush(false, 0);
     }
     fn can_place_used_fire(&mut self, target: [i32; 3]) -> bool {
         let pos = BlockPos::new(target[0], target[1], target[2]);
@@ -13255,6 +13258,7 @@ impl Game<'_> {
                 target,
                 self.remote.is_none(),
                 &mut next_float,
+                Some(self.border.geometry()),
             )
         });
         self.orbs = orbs;
@@ -14136,7 +14140,7 @@ impl Game<'_> {
             self.snap_player_model_pitch();
         }
         self.occupy_bed(head);
-        self.stats.custom("sleep_in_bed", 1);
+        self.award_custom_stat("sleep_in_bed", 1);
         self.trigger_player("minecraft:slept_in_bed");
         self.stats.reset("custom", "minecraft:time_since_rest");
     }
@@ -14818,10 +14822,19 @@ impl Game<'_> {
         if self.remote.is_some() {
             return Ok(());
         }
+        // `DedicatedServer.saveAllChunks` tells the management protocol's clients when a save starts and when
+        // it ends without failing, for every save: the command, the autosave, the pause.
+        let dedicated = self.options.dedicated.is_some();
+        if dedicated {
+            dedicated::events::record_server("saving");
+        }
         self.save_level(wait)?;
         self.save_parked_levels(wait)?;
         self.save_game_metadata()?;
         self.native_world_saved(wait);
+        if dedicated {
+            dedicated::events::record_server("saved");
+        }
         Ok(())
     }
     fn save_game_metadata(&mut self) -> Result<()> {
@@ -14837,12 +14850,17 @@ impl Game<'_> {
         self.save_schedule();
         self.save_warden_tracker();
         self.sync_level();
-        self.store_owner();
+        let stored_owner = self.store_owner();
         write_level_for_role(
             &mut self.level,
             &self.world_root,
             self.options.execution_role,
         )?;
+        // PlayerEvent.SaveToFile for the owner, once level.dat is written.
+        if let Some((uuid, name)) = stored_owner {
+            let directory = horizon_client::lan::playerdata::directory(&self.world_root);
+            self.native_player_save_to_file(uuid, &name, &directory);
+        }
         // PlayerList.saveAll: every placed player saves with the server, to
         // their own file (`PlayerDataStorage.save`); the owner is also in the
         // file level.dat names, which is the one it loads from
@@ -14854,9 +14872,11 @@ impl Game<'_> {
             // The vehicle tree goes into a player's file when they leave
             // (`take_parent_vehicle`); here it stays in the chunk saves.
             let mut host = host;
+            let directory = horizon_client::lan::playerdata::directory(&self.world_root);
             for g in host.hub.guests.iter_mut().filter(|g| g.placed) {
                 self.guest_attachments_into(g);
                 horizon_client::lan::playerdata::save(g, &self.world_root);
+                self.native_player_save_to_file(g.uuid, &g.name, &directory);
             }
             self.lan = Some(host);
         }
@@ -18986,6 +19006,7 @@ impl Game<'_> {
                         if let Some(host) = self.lan.as_mut() {
                             host.hub.reload_resources(sync);
                         }
+                        self.run_native_advancement_grants();
                     }
                     Err(e) => {
                         log::warn!("Horizon: the players are not sent the reloaded data: {e}")

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

@@ -611,13 +611,40 @@ impl Game<'_> {
         for (ai, ci) in hits {
             let a = &tree.list[ai];
             let was = self.adv.progress.done(a);
-            self.adv.progress.grant(&a.id, &a.criteria[ci].name, &date);
+            let criterion = &a.criteria[ci].name;
+            if self.adv.progress.grant(&a.id, criterion, &date) {
+                self.advancement_progress(&a.id, criterion, true);
+            }
             self.progress_changed(ai);
             if !was && self.adv.progress.done(a) {
                 self.award(ai);
             }
         }
     }
+    /// `PlayerAdvancements.award` / `revoke` after a criterion's progress changed.
+    fn advancement_progress(&mut self, advancement: &str, criterion: &str, granted: bool) {
+        if let (Some(player), Some(name)) = (self.lan_acting_uuid, self.lan_acting_name.clone()) {
+            self.native_player_advancement_progress(player, &name, advancement, criterion, granted);
+        }
+    }
+    /// The criteria `CriteriaTriggers.TICK` granted network players in the hub
+    /// (their first tick and a reload), told to the mods.
+    pub(super) fn run_native_advancement_grants(&mut self) {
+        let Some(host) = self.lan.as_mut() else {
+            return;
+        };
+        for batch in std::mem::take(&mut host.hub.native_advancement_grants) {
+            for grant in batch.grants {
+                self.native_player_advancement_progress(
+                    batch.player,
+                    &batch.name,
+                    &grant.advancement,
+                    &grant.criterion,
+                    true,
+                );
+            }
+        }
+    }
     /// `PlayerAdvancements.progressChanged`, kept for a network player's client.
     fn progress_changed(&mut self, index: usize) {
         if self.lan_acting.is_some() {
@@ -692,7 +719,7 @@ impl Game<'_> {
         match result {
             Ok(unlocked) => {
                 self.recipe_unlocked(&unlocked);
-                self.stats.add("used", &stack.item, 1);
+                self.award_stat("used", &stack.item, 1);
                 self.swing_arm();
                 true
             }
@@ -1962,6 +1989,7 @@ impl Game<'_> {
             let was = self.adv.progress.done(a);
             if self.adv.progress.grant(&a.id, c, &date) {
                 changed = true;
+                self.advancement_progress(&a.id, c, true);
                 self.progress_changed(index);
                 if !was && self.adv.progress.done(a) {
                     self.award(index);
@@ -1976,16 +2004,25 @@ impl Game<'_> {
         let a = &tree.list[index];
         self.progress_changed(index);
         match criterion {
-            Some(c) => self.adv.progress.revoke(&a.id, c),
+            Some(c) => self.revoke_criterion(&a.id, c),
             None => {
                 let mut any = false;
                 for c in &a.criteria {
-                    any |= self.adv.progress.revoke(&a.id, &c.name);
+                    any |= self.revoke_criterion(&a.id, &c.name);
                 }
                 any
             }
         }
     }
+    /// `PlayerAdvancements.revoke(holder, criterion)`: the progress change and
+    /// the hook for it.
+    fn revoke_criterion(&mut self, advancement: &str, criterion: &str) -> bool {
+        let revoked = self.adv.progress.revoke(advancement, criterion);
+        if revoked {
+            self.advancement_progress(advancement, criterion, false);
+        }
+        revoked
+    }
 }
 impl Game<'_> {
     /// `ClientAdvancements.update` (ClientboundUpdateAdvancementsPacket):

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

@@ -272,7 +272,7 @@ impl Game<'_> {
             }
             self.post_block_game_event("minecraft:fluid_pickup", pos, self.sculk_actor(), None);
         }
-        self.stats.add("used", &held.item, 1);
+        self.award_stat("used", &held.item, 1);
         let smokey = beehive::smokey(&self.mob_world_base(&[]), pos);
         let key = (pos[0], pos[1], pos[2]);
         if !smokey

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

@@ -873,7 +873,7 @@ impl Game<'_> {
         let Some(book) = &l.book else { return false };
         let pages = view_pages(book.data());
         let page = (l.page.max(0) as usize).min(pages.len().saturating_sub(1));
-        self.stats.custom("interact_with_lectern", 1);
+        self.award_custom_stat("interact_with_lectern", 1);
         self.open_book(BookScreen::View {
             pages,
             page,

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

@@ -51,7 +51,7 @@ impl Game<'_> {
             self.native_campfire_start(pos, &held.item);
             // ItemStack.consumeAndReturn: creative keeps the item.
             self.consume_held();
-            self.stats.custom("interact_with_campfire", 1);
+            self.award_custom_stat("interact_with_campfire", 1);
             self.post_block_game_event(
                 "minecraft:block_change",
                 pos,

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

@@ -66,7 +66,7 @@ impl Game<'_> {
         {
             // addBook: one book goes in (a creative player keeps theirs).
             let book = book.clone();
-            self.stats.add("used", &book.item, 1);
+            self.award_stat("used", &book.item, 1);
             let sound = if &*book.item == "minecraft:enchanted_book" {
                 "minecraft:block.chiseled_bookshelf.insert.enchanted"
             } else {

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

@@ -265,9 +265,9 @@ impl Game<'_> {
                 // hit), in tenths.
                 MotionEvent::Health(HealthEvent::Statistic { name, amount }) => {
                     match *name {
-                        "resisted" => self.stats.custom("damage_resisted", *amount),
-                        "absorbed" => self.stats.custom("damage_absorbed", *amount),
-                        "blocked" => self.stats.custom("damage_blocked_by_shield", *amount),
+                        "resisted" => self.award_custom_stat("damage_resisted", *amount),
+                        "absorbed" => self.award_custom_stat("damage_absorbed", *amount),
+                        "blocked" => self.award_custom_stat("damage_blocked_by_shield", *amount),
                         _ => {}
                     }
                     continue;
@@ -308,8 +308,7 @@ impl Game<'_> {
                 }
             }
             // Player.actuallyHurt: damage_taken in tenths.
-            self.stats
-                .custom("damage_taken", (amount * 10.0).round() as i32);
+            self.award_custom_stat("damage_taken", (amount * 10.0).round() as i32);
             self.combat.entries.push(Entry {
                 damage_type: name,
                 damage: amount,

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

@@ -2202,13 +2202,7 @@ impl Game<'_> {
                         health: 5,
                     });
                     // tryAddFreshEntityWithPassengers refused: ERROR_DUPLICATE_UUID.
-                    if !self.native_entity_joins(
-                        self.next_entity,
-                        "minecraft:experience_orb",
-                        pos,
-                        false,
-                    ) {
-                        self.orbs.pop();
+                    if !self.native_joins_flush(false, self.next_entity) {
                         return Err(err("commands.summon.failed.uuid", &[]));
                     }
                     name = Text::translate("entity.minecraft.experience_orb", &[]);

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

@@ -60,7 +60,7 @@ impl Game<'_> {
         if level < 7 {
             self.composter_add(pos, &layers);
             self.native_compost_item(pos, &stack.item);
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
             self.consume_held();
         }
         // ServerPlayerGameMode.useItemOn: the action was consumed.

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

@@ -49,7 +49,7 @@ impl Game<'_> {
     ) {
         self.emit_consume(consumable, stack, 16);
         // ServerPlayer: the used statistic and the consume_item trigger.
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.trigger_item("minecraft:consume_item", stack);
         // FoodProperties.onConsume, the player's one ConsumableListener.
         if let Some((nutrition, saturation)) = info.food {

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

@@ -1290,9 +1290,9 @@ impl Game<'_> {
         // entity, so a kill by a mob (a tame wolf credited to its owner)
         // leaves it out; ServerPlayer.awardKillScore counts the rest.
         if !killed_by_mob(m) {
-            self.stats.add("killed", &m.kind.id, 1);
+            self.award_stat("killed", &m.kind.id, 1);
         }
-        self.stats.custom("mob_kills", 1);
+        self.award_custom_stat("mob_kills", 1);
         self.score_player_killed(super::commands::Target::Mob(m.id));
         let view = self.mob_entity(m);
         let blow = m.last_damage.map(|(d, _)| self.damage_view(d));
@@ -2103,6 +2103,34 @@ impl Game<'_> {
                         }
                     }
                 }
+                MobEvent::PufferfishSting {
+                    mob,
+                    target,
+                    amount,
+                    source,
+                    poison_ticks,
+                } => {
+                    // Pufferfish.touch: the poison and
+                    // `playSound(PUFFER_FISH_STING, 1, 1)` sit inside the
+                    // `hurtServer` branch, so only a hit that landed poisons
+                    // and stings, at the fish's own position as
+                    // `Entity.playSound` puts it, and not when it is silent.
+                    let landed = self.mob_hits_mob(target, amount, source);
+                    if landed && let Some(t) = self.mobs.iter_mut().find(|m| m.id == target) {
+                        t.add_effect("minecraft:poison", poison_ticks, 0);
+                    }
+                    if landed && let Some(m) = self.mobs.iter_mut().find(|m| m.id == mob) {
+                        let at = [m.position.x, m.position.y, m.position.z];
+                        if !m.silent {
+                            self.handle_mob_events(vec![MobEvent::Sound(
+                                "entity.puffer_fish.sting",
+                                at,
+                                1.0,
+                                1.0,
+                            )])?;
+                        }
+                    }
+                }
                 MobEvent::SonicBoom {
                     target,
                     attacker,
@@ -2946,7 +2974,7 @@ impl Game<'_> {
                 super::commands::Target::Guest,
             );
             self.for_player(who, |g| {
-                g.stats.custom("animals_bred", 1);
+                g.award_custom_stat("animals_bred", 1);
                 g.trigger_bred(&parent, &partner_view, (!turtle).then_some(&child));
             });
         }
@@ -3883,7 +3911,7 @@ impl Game<'_> {
         if rang {
             let _ = self.process_level_events();
             if p.owner == Some(Who::Player) {
-                self.stats.custom("bell_ring", 1);
+                self.award_custom_stat("bell_ring", 1);
             }
         }
     }
@@ -4101,7 +4129,7 @@ impl Game<'_> {
             let _ = self.process_level_events();
             self.native_target_hit(self.dim.id(), pos, strength);
             if p.owner == Some(Who::Player) && (p.guest.is_none() || p.guest == self.lan_acting) {
-                self.stats.custom("target_hit", 1);
+                self.award_custom_stat("target_hit", 1);
                 let kind = if p
                     .arrow
                     .as_ref()
@@ -4734,7 +4762,7 @@ impl Game<'_> {
             // flies as: the splash happens where the hit was, a lingering
             // potion's cloud sits at the mob it hit (ThrownLingeringPotion),
             // and the potion that lands names the hurt it deals.
-            (ProjectileKind::Potion(stack), hit) => {
+            (ProjectileKind::Potion(stack, _), hit) => {
                 let block = match hit {
                     Hit::Block { pos, face, .. } => Some((
                         pos,
@@ -6111,7 +6139,7 @@ impl Game<'_> {
         if let Some(done) = self.use_spawn_egg_on_spawner(hit.pos, &spawner_id, data.as_ref()) {
             if done {
                 self.swing_arm();
-                self.stats.add("used", &stack.item, 1);
+                self.award_stat("used", &stack.item, 1);
                 self.consume_held();
             }
             return Ok(true);
@@ -6142,7 +6170,7 @@ impl Game<'_> {
         }
         self.apply_spawn_egg_entity_data(id, stack);
         self.post_block_game_event("minecraft:entity_place", p, Some(Who::Player), None);
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.swing_arm();
         if !self.creative
             && let Some(s) = self.held_mut().as_mut()

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

@@ -119,7 +119,7 @@ impl Game<'_> {
         };
         let stack = stack.clone();
         self.block_entity_event(pos, 1, WOBBLE_POSITIVE);
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         // consumeAndReturn(1): one item goes in (a creative player keeps theirs).
         let inserted = match &mut pot_item {
             Some(p) => {

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

@@ -641,6 +641,18 @@ struct ServerState {
     force_game_mode: bool,
 }
 
+/// `MinecraftServer.isAutoSave`: all of Horizon's server levels share this save flag.
+fn auto_save(state: &ServerState) -> bool {
+    state.autosave
+}
+
+/// `MinecraftServer.setAutoSave`: enable or disable periodic saves and report whether it changed.
+fn set_auto_save(state: &mut ServerState, enabled: bool) -> bool {
+    let changed = state.autosave != enabled;
+    state.autosave = enabled;
+    changed
+}
+
 /// The dedicated-only commands' replies vanilla sends with `broadcast`
 /// (`sendSuccess(..., true)`): the operators hear of them.
 const BROADCAST: &[&str] = &[
@@ -1063,8 +1075,12 @@ impl Game<'_> {
                 self.save_game()?;
             }
             if !paused && !state.autosave {
-                // `save-off`: the periodic save inside the tick is skipped.
-                self.ticks = self.ticks.max(1);
+                // `MinecraftServer.autoSave` keeps its schedule while every level's
+                // `noSave` flag is set, but writes nothing. The tick below counts down
+                // once, so reset one tick early when this save would have been due.
+                if self.ticks_until_autosave <= 1 {
+                    self.ticks_until_autosave = self.next_autosave_interval() + 1;
+                }
             }
             // MinecraftServer.tickServer: while paused only the connections run.
             // `MinecraftServer.runServer` catches what the tick throws, writes the crash
@@ -1372,19 +1388,17 @@ impl Game<'_> {
                 }
             }
             "save-off" => {
-                if state.autosave {
-                    state.autosave = false;
+                if set_auto_save(state, false) {
                     self.console_reply(Text::translate("commands.save.disabled", &[]));
                 } else {
                     self.console_reply(Text::translate("commands.save.alreadyOff", &[]));
                 }
             }
             "save-on" => {
-                if state.autosave {
-                    self.console_reply(Text::translate("commands.save.alreadyOn", &[]));
-                } else {
-                    state.autosave = true;
+                if set_auto_save(state, true) {
                     self.console_reply(Text::translate("commands.save.enabled", &[]));
+                } else {
+                    self.console_reply(Text::translate("commands.save.alreadyOn", &[]));
                 }
             }
             "list" => {

crates/horizon-client/src/game/dedicated/events.rs

@@ -21,11 +21,20 @@ static EVENTS: Mutex<Events> = Mutex::new(Events {
 
 /// Records one event: its kind, the player's name and UUID, and what else it says.
 pub(in crate::game) fn record(kind: &str, name: &str, uuid: u128, mut fields: Value) {
+    fields["name"] = name.into();
+    fields["uuid"] = horizon_protocol::crypto::uuid_string(uuid).into();
+    push(kind, fields);
+}
+
+/// Records an event of the server itself, with no player (`saving` and `saved`, around a world save).
+pub(in crate::game) fn record_server(kind: &str) {
+    push(kind, json!({}));
+}
+
+fn push(kind: &str, mut fields: Value) {
     let mut events = EVENTS.lock().unwrap_or_else(|e| e.into_inner());
     fields["seq"] = events.next.into();
     fields["type"] = kind.into();
-    fields["name"] = name.into();
-    fields["uuid"] = horizon_protocol::crypto::uuid_string(uuid).into();
     fields["time"] = std::time::SystemTime::now()
         .duration_since(std::time::UNIX_EPOCH)
         .map_or(0, |d| d.as_millis() as u64)
@@ -52,6 +61,7 @@ pub(super) fn since(since: u64) -> Value {
 mod tests {
     use super::*;
 
+    // One test: the events are one process-wide list, so two tests recording at once would count each other's.
     #[test]
     fn events_are_numbered_and_read_from_a_number() {
         let first = since(u64::MAX)["next"].as_u64().unwrap();
@@ -65,5 +75,11 @@ mod tests {
         assert_eq!(events[1]["message"], "hi");
         assert_eq!(events[1]["uuid"], "00000000-0000-0000-0000-000000000001");
         assert_eq!(since(first + 1)["events"].as_array().unwrap().len(), 1);
+        // An event of the server itself (a world save) carries no player.
+        record_server("saving");
+        let event = &since(first + 2)["events"][0];
+        assert_eq!(event["type"], "saving");
+        assert_eq!(event["seq"].as_u64(), Some(first + 3));
+        assert!(event.get("name").is_none() && event.get("uuid").is_none());
     }
 }

crates/horizon-client/src/game/dedicated/management.rs

@@ -3,7 +3,7 @@
 //! `AllowlistService`, `BanlistService`, `IpBanlistService` and `OperatorService` on the running server's lists. Players are found as
 //! `MinecraftPlayerListService.getUser` finds them, each change is logged as `JsonRpcLogger` logs it, and the
 //! players a change shuts out are disconnected. The supervisor answers with the lists, from their files.
-use super::{GAME_MODES, ServerState, log};
+use super::{GAME_MODES, ServerState, auto_save, log, set_auto_save};
 use crate::game::Game;
 use horizon_client::{
     command::vanilla::DIFFICULTIES,
@@ -49,6 +49,21 @@ impl Game<'_> {
         let entries = body["entries"].as_array().cloned().unwrap_or_default();
         let lists = state.lists.clone();
         match body["method"].as_str().unwrap_or_default() {
+            "serversettings/autosave" => {
+                return json!({ "value": auto_save(state) });
+            }
+            "serversettings/autosave/set" => {
+                let Some(enabled) = body["value"].as_bool() else {
+                    return json!({ "error": "autosave must be a boolean" });
+                };
+                rpc(format!(
+                    "Update autosave from {} to {}",
+                    auto_save(state),
+                    enabled
+                ));
+                set_auto_save(state, enabled);
+                return json!({ "value": auto_save(state) });
+            }
             "serversettings/motd" => {
                 return json!({
                     "value": self.lan.as_ref().map(|lan| lan.hub.lan.shared.motd()).unwrap_or_default()

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

@@ -1316,8 +1316,8 @@ impl Game<'_> {
         view: &horizon_client::advancements::EntityView,
         blow: Option<(DamageKind, bool)>,
     ) {
-        self.stats.add("killed", "minecraft:ender_dragon", 1);
-        self.stats.custom("mob_kills", 1);
+        self.award_stat("killed", "minecraft:ender_dragon", 1);
+        self.award_custom_stat("mob_kills", 1);
         self.score_player_killed(super::commands::Target::Mob(id));
         // KilledTrigger: the damage source `die` was given.
         let blow = blow.map(|(kind, by_player)| {

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

@@ -21,6 +21,7 @@ use horizon_core::geometry::{Aabb, Direction, Vec3};
 use horizon_core::position::BlockPos;
 use horizon_world::nbt::Tag;
 use horizon_world::{level::data::PushReaction, piston_push};
+use std::borrow::Cow;
 use std::collections::{HashMap, HashSet};
 
 /// What `Entity.thunderHit` does to a kind: it sets the entity on fire and
@@ -61,6 +62,8 @@ pub(super) trait Entity: EntityRules {
     /// What a selector finds this entity as (`@e`), or `None` for one it cannot
     /// name yet. Required, so a new kind states which.
     fn selector_target(&self) -> Option<Target>;
+    /// The entity type id a native mod's join hook names (`minecraft:oak_boat`).
+    fn native_type(&self) -> Cow<'static, str>;
     /// Saves entity `index` of this kind into its chunk's entity list: the
     /// chunk and the NBT when it lies in `keys` and is saved with its chunk.
     /// Required, so a new kind states how it saves.
@@ -313,6 +316,15 @@ macro_rules! define_entity_handles {
                     $(.chain((0..self$(.$list)+.len()).map(EntityHandle::$kind)))*
             }
 
+            /// Takes the entity out of its list (`Entity.discard` before it ever ticked).
+            pub(super) fn discard_entity(&mut self, handle: EntityHandle) {
+                match handle {
+                    $(EntityHandle::$kind(i) => {
+                        self$(.$list)+.remove(i);
+                    })*
+                }
+            }
+
             /// [`Self::entity_handles`], last of each list first, so the
             /// caller can remove the entity it is on.
             pub(super) fn entity_handles_rev(&self) -> impl Iterator<Item = EntityHandle> + use<> {
@@ -452,6 +464,9 @@ impl Game<'_> {
 }
 
 impl Entity for Mob {
+    fn native_type(&self) -> Cow<'static, str> {
+        super::native_hooks::mob_kind(self).into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -534,6 +549,9 @@ impl Entity for Mob {
 }
 
 impl Entity for ItemEntity {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:item".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -576,6 +594,9 @@ impl Entity for ItemEntity {
 }
 
 impl Entity for ExperienceOrb {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:experience_orb".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -615,6 +636,9 @@ impl Entity for ExperienceOrb {
 }
 
 impl Entity for Boat {
+    fn native_type(&self) -> Cow<'static, str> {
+        self.entity_type().into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -658,6 +682,9 @@ impl Entity for Boat {
 }
 
 impl Entity for Minecart {
+    fn native_type(&self) -> Cow<'static, str> {
+        self.kind.id().into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -711,6 +738,9 @@ fn armor_stand_size(stand: &ArmorStand) -> (f64, f64) {
 }
 
 impl Entity for ArmorStand {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:armor_stand".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -783,6 +813,9 @@ impl Entity for ArmorStand {
 }
 
 impl Entity for PrimedTnt {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:tnt".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -824,6 +857,9 @@ impl Entity for PrimedTnt {
 }
 
 impl Entity for FallingBlock {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:falling_block".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -841,6 +877,9 @@ impl Entity for FallingBlock {
 }
 
 impl Entity for Projectile {
+    fn native_type(&self) -> Cow<'static, str> {
+        self.kind.id().into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -901,6 +940,9 @@ impl Entity for Projectile {
 }
 
 impl Entity for Rocket {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:firework_rocket".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,
@@ -933,6 +975,9 @@ impl Entity for Rocket {
 }
 
 impl Entity for ThrownTrident {
+    fn native_type(&self) -> Cow<'static, str> {
+        "minecraft:trident".into()
+    }
     fn save_nbt(
         game: &mut Game<'_>,
         index: usize,

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

@@ -797,9 +797,8 @@ impl Game<'_> {
             // centre of its box.
             let (lo, hi) = self.paintings[i].bounds();
             let at = [0, 1, 2].map(|k| (lo[k] + hi[k]) / 2.0);
-            if blast_reaches(center, diameter, at) {
-                self.break_painting(i, false);
-            } else {
+            // A painting a mod keeps stays at `i`.
+            if !(blast_reaches(center, diameter, at) && self.break_painting(i, false)) {
                 i += 1;
             }
         }

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

@@ -280,7 +280,7 @@ impl Game<'_> {
                     .get("minecraft:fishes")
                     .is_some_and(|t| t.contains(stack.item.as_str()))
                 {
-                    self.stats.custom("fish_caught", 1);
+                    self.award_custom_stat("fish_caught", 1);
                 }
                 let mut item = ItemStack {
                     item: Arc::from(stack.item.as_str()),

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

@@ -136,6 +136,28 @@ impl Game<'_> {
         self.native_hanging_place(uuid, &name, kind, pos, &mut cancel);
         cancel
     }
+    /// Asks the mods whether a hanging entity of type `kind` at `pos` may
+    /// break (`native_hanging_break`): true when one cancelled it. A break by
+    /// a player is asked only for the acting guest, with them as the player;
+    /// a break by anything else is asked with none.
+    pub(super) fn hanging_break_cancelled(
+        &mut self,
+        kind: &str,
+        pos: [i32; 3],
+        by_player: bool,
+    ) -> bool {
+        let player = if by_player {
+            let Some(uuid) = self.lan_acting_uuid else {
+                return false;
+            };
+            Some(uuid)
+        } else {
+            None
+        };
+        let mut cancel = false;
+        self.native_hanging_break(player, kind, pos, &mut cancel);
+        cancel
+    }
     /// `ItemFrameItem.useOn`.
     pub(super) fn place_item_frame(&mut self, hit: &Hit, stack: &ItemStack) -> bool {
         let glow = match &*stack.item {
@@ -296,6 +318,12 @@ impl Game<'_> {
         }
         let with_frame = self.item_frames[i].item.is_none();
         let entity_id = self.item_frames[i].id;
+        if with_frame {
+            let (kind, pos) = (self.item_frames[i].kind(), self.item_frames[i].pos);
+            if self.hanging_break_cancelled(kind, pos, true) {
+                return true;
+            }
+        }
         let old_item = self.item_frames[i]
             .item
             .as_ref()
@@ -403,7 +431,11 @@ impl Game<'_> {
                 ((c[0] - blast[0]).powi(2) + (c[1] - blast[1]).powi(2) + (c[2] - blast[2]).powi(2))
                     .sqrt()
                     / diameter;
-            if dist > 1.0 || self.item_frames[i].fixed {
+            let (kind, pos) = (self.item_frames[i].kind(), self.item_frames[i].pos);
+            if dist > 1.0
+                || self.item_frames[i].fixed
+                || self.hanging_break_cancelled(kind, pos, false)
+            {
                 i += 1;
                 continue;
             }
@@ -432,7 +464,8 @@ impl Game<'_> {
             if self.item_frames[i].check_interval >= 100 {
                 self.item_frames[i].check_interval = 0;
                 let f = self.item_frames[i].clone();
-                if !self.frame_survives(&f) {
+                if !self.frame_survives(&f) && !self.hanging_break_cancelled(f.kind(), f.pos, false)
+                {
                     self.item_frames.remove(i);
                     self.audio
                         .play(&sound(&f, "break"), Some(center(&f)), 1.0, 1.0);

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

@@ -44,7 +44,7 @@ impl Game<'_> {
         if used {
             self.swing_arm();
             // ItemStack.useOn: an item interaction counts as a use.
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
             self.consume_held();
         }
         Ok(used)
@@ -89,7 +89,7 @@ impl Game<'_> {
         );
         self.damage_held(1);
         // ItemStack.useOn: an item interaction counts as a use.
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.swing_arm();
         // ServerPlayerGameMode.useItemOn: a consuming useOn reports it.
         self.trigger_block("minecraft:item_used_on_block", pos, stack);

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

@@ -834,7 +834,7 @@ impl Game<'_> {
         if let Some(mut host) = self.lan.take() {
             self.flush_native_net(&mut host);
             // PlayerList.removeAll: the owner and every guest leave the game.
-            host.award_leave_game_to_all();
+            self.award_leave_game_to_all(&mut host);
             self.save_leaving_guests(&mut host);
             let conns: Vec<u32> = host.hub.guests.iter().map(|g| g.conn).collect();
             for conn in conns {

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

@@ -143,7 +143,7 @@ impl Game<'_> {
         if !self.creative {
             self.consume_held();
         }
-        self.stats.custom("play_record", 1);
+        self.award_custom_stat("play_record", 1);
         self.world.block_entities.insert(
             (pos[0], pos[1], pos[2]),
             BlockEntity::Jukebox(Jukebox {

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

@@ -191,29 +191,48 @@ pub(super) struct LanHost {
     pub(super) states: lan::entity::States,
 }
 
-impl LanHost {
+impl Game<'_> {
     /// `PlayerList.remove`: `player.awardStat(Stats.LEAVE_GAME)` before the
-    /// player is saved. Once per guest, however often they are saved.
-    pub(super) fn award_leave_game(&mut self, conn: u32) {
-        if let Some(play) = self.play.get_mut(&conn)
-            && !play.left_game
-        {
-            play.left_game = true;
+    /// player is saved, heard by native mods first. Once per guest, however
+    /// often they are saved.
+    pub(super) fn award_leave_game(
+        &mut self,
+        host: &mut LanHost,
+        conn: u32,
+        player: u128,
+        name: &str,
+    ) {
+        let Some(play) = host.play.get_mut(&conn) else {
+            return;
+        };
+        if std::mem::replace(&mut play.left_game, true) {
+            return;
+        }
+        let mut cancel = false;
+        self.native_player_stat_award(
+            player,
+            name,
+            "minecraft:custom",
+            "minecraft:leave_game",
+            1,
+            &mut cancel,
+        );
+        if !cancel && let Some(play) = host.play.get_mut(&conn) {
             play.stats.custom("leave_game", 1);
         }
     }
 
     /// `PlayerList.removeAll`: every player who joined leaves with the world.
-    pub(super) fn award_leave_game_to_all(&mut self) {
-        let conns: Vec<u32> = self
+    pub(super) fn award_leave_game_to_all(&mut self, host: &mut LanHost) {
+        let players: Vec<(u32, u128, String)> = host
             .hub
             .guests
             .iter()
             .filter(|g| g.placed)
-            .map(|g| g.conn)
+            .map(|g| (g.conn, g.uuid, g.name.clone()))
             .collect();
-        for conn in conns {
-            self.award_leave_game(conn);
+        for (conn, player, name) in players {
+            self.award_leave_game(host, conn, player, &name);
         }
     }
 }
@@ -1334,7 +1353,7 @@ impl Game<'_> {
         let Some(mut host) = self.lan.take() else {
             return;
         };
-        host.award_leave_game_to_all();
+        self.award_leave_game_to_all(&mut host);
         self.save_leaving_guests(&mut host);
         host.hub.disconnect_all();
         // Give the writer threads a moment to flush the disconnect packets.
@@ -1394,10 +1413,14 @@ impl Game<'_> {
         guest: &mut horizon_client::lan::guest::Guest,
     ) {
         self.guest_attachments_into(guest);
-        if guest.placed && host.owner.as_ref().is_some_and(|o| o.uuid == guest.uuid) {
-            playerdata::save_owner(guest, &mut self.level, &self.world_root);
-        } else if guest.placed {
-            playerdata::save(guest, &self.world_root);
+        if guest.placed {
+            if host.owner.as_ref().is_some_and(|o| o.uuid == guest.uuid) {
+                playerdata::save_owner(guest, &mut self.level, &self.world_root);
+            } else {
+                playerdata::save(guest, &self.world_root);
+            }
+            let directory = playerdata::directory(&self.world_root);
+            self.native_player_save_to_file(guest.uuid, &guest.name, &directory);
         }
         self.save_guest_records(host, guest);
     }
@@ -1593,35 +1616,28 @@ impl Game<'_> {
         host.play.entry(conn).or_default().stats = stats;
     }
     /// The integrated server's owner into the world's player, for `Level::write`.
-    pub(super) fn store_owner(&mut self) {
-        let Some(uuid) = self
-            .lan
-            .as_ref()
-            .and_then(|h| h.owner.as_ref())
-            .map(|o| o.uuid)
-        else {
-            return;
-        };
-        let Some((riding, dim, others)) = self.lan.as_ref().and_then(|h| {
+    /// Returns the owner's uuid and name when they were stored.
+    pub(super) fn store_owner(&mut self) -> Option<(u128, String)> {
+        let uuid = self.lan.as_ref().and_then(|h| h.owner.as_ref())?.uuid;
+        let (riding, dim, others) = self.lan.as_ref().and_then(|h| {
             let g = h.hub.guests.iter().find(|g| g.uuid == uuid && g.placed)?;
             let others = self.ridden_by_others(&h.hub.guests, &g.dimension, Some(uuid), true);
             Some((g.vehicle, g.dimension.clone(), others))
-        }) else {
-            return;
-        };
+        })?;
         // The vehicle the owner rides (`ServerPlayer.saveParentVehicle`).
         let vehicle = self
             .parent_vehicle_in(None, &dim, riding, &others, false)
             .map(|(tag, _)| tag);
-        let Some(host) = &self.lan else {
-            return;
-        };
+        let host = self.lan.as_ref()?;
+        let mut stored = None;
         if let Some(g) = host.hub.guests.iter().find(|g| g.uuid == uuid && g.placed) {
             playerdata::store(g, &mut self.level, vehicle);
             self.save_guest_records(host, g);
+            stored = Some(g.name.clone());
         } else if let Some(saved) = host.owner.as_ref().and_then(|o| o.saved.as_ref()) {
             self.level.position = saved.position;
         }
+        stored.map(|name| (uuid, name))
     }
 
     /// The world's default game mode (`defaultgamemode`).
@@ -1883,7 +1899,7 @@ impl Game<'_> {
                     }
                     self.lan_crafting_left(&mut host, &mut guest);
                     if guest.placed {
-                        host.award_leave_game(guest.conn);
+                        self.award_leave_game(&mut host, guest.conn, guest.uuid, &guest.name);
                     }
                     // PlayerList.remove: the vehicle it alone rides goes too.
                     self.take_parent_vehicle(&mut host, &mut guest);
@@ -2007,6 +2023,14 @@ impl Game<'_> {
                 .take()
                 .expect("the hub is back after the quiet commands");
         }
+        if !host.hub.native_advancement_grants.is_empty() {
+            self.lan = Some(host);
+            self.run_native_advancement_grants();
+            host = self
+                .lan
+                .take()
+                .expect("the hub is back after the advancement grants");
+        }
         if !host.hub.native_menu_events.is_empty() {
             self.lan = Some(host);
             self.run_native_menu_events();
@@ -2198,6 +2222,14 @@ impl Game<'_> {
                 .take()
                 .expect("the hub is back after the mod messages");
         }
+        if !host.hub.native_advancement_grants.is_empty() {
+            self.lan = Some(host);
+            self.run_native_advancement_grants();
+            host = self
+                .lan
+                .take()
+                .expect("the hub is back after the advancement grants");
+        }
         if !host.hub.native_menu_events.is_empty() {
             self.lan = Some(host);
             self.run_native_menu_events();
@@ -2276,6 +2308,9 @@ impl Game<'_> {
         };
         self.guest_attachments
             .insert(g.uuid, std::mem::take(&mut g.attachments));
+        // PlayerEvent.LoadFromFile: the player's data is read and applied,
+        // the player not yet placed.
+        self.native_player_load_from_file(g.uuid, &g.name, &playerdata::directory(&root));
         if !known || force {
             g.game_mode = default_mode;
         }

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

@@ -103,7 +103,7 @@ pub(super) struct GuestPlay {
     /// `ServerPlayer.getStats` and the inventory `inventory_changed` last saw.
     pub(super) stats: super::stats::Stats,
     /// `Stats.LEAVE_GAME` is counted: a guest is saved more than once on the
-    /// way out, the statistic is awarded once (`LanHost::award_leave_game`).
+    /// way out, the statistic is awarded once (`Game::award_leave_game`).
     pub(super) left_game: bool,
     last_inventory: u64,
     /// `ServerPlayer.levitationStartPos` and `levitationStartTime`.
@@ -3453,6 +3453,10 @@ impl Game<'_> {
         };
         xp.respawn(self.ui.rules.bool("keep_inventory") || g.game_mode == SPECTATOR);
         (g.xp_level, g.xp_progress, g.xp_total) = (xp.level, xp.progress, xp.total);
+        // PlayerEvent.Clone, at the end of `restoreFrom`: the data is copied,
+        // the new player not yet placed.
+        let (cloned, name) = (g.uuid, g.name.clone());
+        self.native_player_clone(cloned, &name, true);
         let clock_rate = self.network_clock_rate();
         let ctx = TickCtx {
             world: &mut self.world,
@@ -4183,7 +4187,7 @@ impl Game<'_> {
             for event in &events {
                 if let MotionEvent::Fall(horizon_client::landing::FallEvent::Statistic(cm)) = event
                 {
-                    game.stats.custom("fall_one_cm", *cm);
+                    game.award_custom_stat("fall_one_cm", *cm);
                 }
             }
             game.record_combat(&events);

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

@@ -633,7 +633,7 @@ impl Game<'_> {
                 // `potion_contents`, whose effects the guest's splash and
                 // whose colour its drawing need. A plain splash potion is the
                 // client's default and is not sent.
-                K::Potion(stack) if stack.extra.is_some() || stack.count != 1 => {
+                K::Potion(stack, _) if stack.extra.is_some() || stack.count != 1 => {
                     e.meta.push((
                         8,
                         serializer::ITEM_STACK,

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

@@ -320,9 +320,9 @@ impl Game<'_> {
             if died {
                 match s.attacker {
                     Some(conn) => {
-                        self.as_guest(host, conn, |g| g.stats.custom("player_kills", 1));
+                        self.as_guest(host, conn, |g| g.award_custom_stat("player_kills", 1));
                     }
-                    None => self.stats.custom("player_kills", 1),
+                    None => self.award_custom_stat("player_kills", 1),
                 }
             }
         }

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

@@ -390,7 +390,7 @@ impl Game<'_> {
         // Player.onEnchantmentPerformed, and EnchantmentMenu's awardStat(ENCHANT_ITEM).
         self.as_guest(host, conn, |game| {
             game.give_levels(-need);
-            game.stats.custom("enchant_item", 1);
+            game.award_custom_stat("enchant_item", 1);
             // CriteriaTriggers.ENCHANTED_ITEM, with the levels it cost.
             game.trigger_enchanted_item(&enchanted, need);
         });

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

@@ -240,7 +240,7 @@ impl Game<'_> {
             self.mace_hurt_enemy(index);
         }
         if weapon.is_some() {
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
         }
         self.post_attack(index);
         // MaceItem.postHurtEnemy
@@ -323,7 +323,7 @@ impl Game<'_> {
             .get(&stack.item)
             .is_some_and(|i| i.weapon_damage.is_some())
         {
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
         }
         self.post_attack_bursts(&stack, "minecraft:player");
         // MaceItem.postHurtEnemy
@@ -352,7 +352,7 @@ impl Game<'_> {
             .get(&stack.item)
             .is_some_and(|i| i.weapon_damage.is_some())
         {
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
         }
         self.post_attack_bursts(&stack, "minecraft:armor_stand");
         // MaceItem.postHurtEnemy

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

@@ -1178,7 +1178,7 @@ impl Game<'_> {
             return true;
         }
         self.trigger_block("minecraft:item_used_on_block", hit.pos, stack);
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.swing_arm();
         true
     }
@@ -1224,7 +1224,7 @@ impl Game<'_> {
             self.consume_held();
             self.give_or_drop_stack(locked);
         }
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.swing_arm();
         true
     }

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

@@ -258,6 +258,87 @@ impl Game<'_> {
     }
 }
 
+/// Entities joining the level (`native_entity_join_level`), for every kind in
+/// the entity walk. Kept out of `native_hooks.rs`, whose lines may not hold macros.
+impl Game<'_> {
+    /// Tells `native_entity_join_level` once for every entity added since the
+    /// last call, of any kind, in the order they were created (ids count up
+    /// from one counter). A mod that cancels takes the entity back out here,
+    /// before it ticks again, and `/summon` of it fails (`joins_canceled`).
+    /// `loaded_from_disk` is for the entities that came with a chunk. Returns
+    /// whether `watch` (an id, or 0) is still in the level. Walks the lists
+    /// with static dispatch and allocates nothing but the kind name of an
+    /// entity it announces; nothing runs when no mod is loaded or on a client
+    /// of a server (which tells nothing).
+    pub(super) fn native_joins_flush(&mut self, loaded_from_disk: bool, watch: u32) -> bool {
+        use super::entity::Entity;
+        if self.remote.is_some() || crate::mod_api::mods().is_empty() {
+            return true;
+        }
+        for t in &mut self.tnts {
+            super::lan_entities::assign_entity_id(&mut self.next_entity, &mut t.id);
+        }
+        for f in &mut self.falling {
+            super::lan_entities::assign_entity_id(&mut self.next_entity, &mut f.id);
+        }
+        for p in &mut self.creatures.projectiles {
+            super::lan_entities::assign_entity_id(&mut self.next_entity, &mut p.id);
+        }
+        for t in &mut self.tridents {
+            super::lan_entities::assign_entity_id(&mut self.next_entity, &mut t.id);
+        }
+        for r in &mut self.rockets {
+            super::lan_entities::assign_entity_id(&mut self.next_entity, &mut r.id);
+        }
+        let mut kept = true;
+        while let Some((handle, id)) = self.next_unannounced() {
+            self.persist.joined_mark = id;
+            let (kind, at) = super::entity::with_entity!(self, handle, e => {
+                (e.native_type(), e.position())
+            });
+            let mut canceled = false;
+            let dimension = self.dim.id();
+            self.native_entity_join_level(
+                dimension,
+                id,
+                &kind,
+                [at.x, at.y, at.z],
+                loaded_from_disk,
+                &mut canceled,
+            );
+            if canceled {
+                self.persist.joins_canceled += 1;
+                self.forget_entity(id);
+                // Handles are indexes: the entity is taken out before any
+                // other change to its list.
+                self.discard_entity(handle);
+                kept &= id != watch;
+            }
+        }
+        kept
+    }
+    /// The entity with the lowest id above the last one announced, by handle.
+    fn next_unannounced(&self) -> Option<(super::entity::EntityHandle, u32)> {
+        let mark = self.persist.joined_mark;
+        let mut best: Option<(super::entity::EntityHandle, u32)> = None;
+        for handle in self.entity_handles() {
+            let id = {
+                use super::entity::Entity;
+                super::entity::with_entity!(self, handle, e => e.id())
+            };
+            if id > mark && best.is_none_or(|(_, b)| id < b) {
+                best = Some((handle, id));
+            }
+        }
+        best
+    }
+    /// Entities that were moved, not added (a portal's arrival keeps being
+    /// silent): everything now in the level counts as announced.
+    pub(super) fn native_joins_skip(&mut self) {
+        self.persist.joined_mark = self.persist.joined_mark.max(self.next_entity);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

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

@@ -296,8 +296,10 @@
 //! `native_extract_item`, `native_move_items`, and `native_dimension` for a
 //! machine's tick, in `machines/native_items.rs`).
 //!
-//! API 47 adds entities joining a level (`native_entity_join_level`), for
-//! item entities and experience orbs so far.
+//! API 47 adds entities joining a level (`native_entity_join_level`); it tells
+//! every kind the game keeps in its entity lists (items, orbs, mobs, boats,
+//! minecarts, armor stands, TNT, falling blocks, projectiles, rockets,
+//! tridents).
 //!
 //! API 46 adds bounded world-space rim and colored-light requests
 //! (`native_visuals`) and opt-in texture-matched emissive material
@@ -3395,6 +3397,25 @@ impl Game<'_> {
     ) {
         mod_api::dispatch_hanging_place(self, mod_api::mods(), player, name, kind, pos, cancel);
     }
+    /// An item frame (`minecraft:item_frame`, `minecraft:glow_item_frame`) or
+    /// a painting (`minecraft:painting`), `kind` its entity type and `pos` the
+    /// block it hangs in, is about to break: a server player's hit
+    /// (`player`, their state swapped in, so `native_tell` answers them), a
+    /// blast, or the wall it hangs on gone (`player` None for both). Where
+    /// `BlockAttachedEntity.hurtServer` and its survival check would kill
+    /// it, before anything drops or sounds. Set `cancel` and it stays, as it
+    /// was. A hit that only takes the item out of a frame does not break the
+    /// frame and is not asked. The game's own player's hit is not asked, nor
+    /// is `/kill`. @API:native_hanging_break@.
+    pub(super) fn native_hanging_break(
+        &mut self,
+        player: Option<u128>,
+        kind: &str,
+        pos: [i32; 3],
+        cancel: &mut bool,
+    ) {
+        mod_api::dispatch_hanging_break(self, mod_api::mods(), player, kind, pos, cancel);
+    }
     /// A server player empties a bucket at `pos` (`fluid`: `minecraft:water`,
     /// `minecraft:lava`, `minecraft:powder_snow`; a fish or axolotl bucket
     /// empties `minecraft:water`): where `BucketItem.use` has found the block
@@ -3553,6 +3574,57 @@ impl Game<'_> {
     ) {
         mod_api::dispatch_player_advancement_done(self, mod_api::mods(), player, name, advancement);
     }
+    /// A criterion of a server player's advancement was granted or revoked,
+    /// after its progress changed and before any completion rewards, except
+    /// the `minecraft:tick` criteria granted on a network player's first tick
+    /// or a reload, which are heard after that tick's rewards and packets. A
+    /// grant or revoke that changes nothing is not heard. `granted` is false for a
+    /// revoke. Helpers looking up the guest through `self.lan` may find
+    /// nothing during its packet. @API:player_advancement_progress@.
+    pub(super) fn native_player_advancement_progress(
+        &mut self,
+        player: u128,
+        name: &str,
+        advancement: &str,
+        criterion: &str,
+        granted: bool,
+    ) {
+        mod_api::dispatch_player_advancement_progress(
+            self,
+            mod_api::mods(),
+            player,
+            name,
+            advancement,
+            criterion,
+            granted,
+        );
+    }
+    /// A statistic is about to be awarded to a server player, before its count
+    /// and scoreboard criteria change. `stat_type` and `stat` are ids such as
+    /// `minecraft:mined` and `minecraft:stone`, and `value` the amount. Set
+    /// `cancel` to award nothing. Helpers looking up the guest through
+    /// `self.lan` may find nothing during its packet. Server-side.
+    /// @API:player_stat_award@.
+    pub(super) fn native_player_stat_award(
+        &mut self,
+        player: u128,
+        name: &str,
+        stat_type: &str,
+        stat: &str,
+        value: i32,
+        cancel: &mut bool,
+    ) {
+        mod_api::dispatch_player_stat_award(
+            self,
+            mod_api::mods(),
+            player,
+            name,
+            stat_type,
+            stat,
+            value,
+            cancel,
+        );
+    }
     /// A server player's experience points are about to increase from an orb pickup,
     /// after mending has taken its share. Change `amount` to change the points
     /// added. The player's state is not swapped in, so helpers that look them up
@@ -5294,6 +5366,48 @@ impl Game<'_> {
     pub(super) fn native_player_respawned(&mut self, player: u128, name: &str) {
         mod_api::dispatch_player_respawned(self, mod_api::mods(), player, name);
     }
+    /// A player was saved to the world's store (NeoForge's
+    /// `PlayerEvent.SaveToFile`, `PlayerList.save`): when they leave or the
+    /// world closes, when the dedicated server saves everyone, and for an
+    /// integrated server's owner when the world saves them. LAN guests are
+    /// not heard on integrated autosaves. Once for each save. `directory`
+    /// is the world's player directory (`players/data`): write your own file
+    /// there, named `<uuid>.<suffix>`, never the player's `.dat`. The player
+    /// may be leaving, so no player's state is swapped in. Not cancellable.
+    pub(super) fn native_player_save_to_file(
+        &mut self,
+        player: u128,
+        name: &str,
+        directory: &std::path::Path,
+    ) {
+        mod_api::dispatch_player_save_to_file(self, mod_api::mods(), player, name, directory);
+    }
+    /// A player was loaded from the world's save (NeoForge's
+    /// `PlayerEvent.LoadFromFile`, `PlayerList.loadPlayerData`): their `.dat`
+    /// has been read and applied, and they are not placed in a level yet.
+    /// `directory` is the world's player directory (`players/data`): a mod
+    /// reads its own file there, named `<uuid>.<suffix>` as
+    /// `getPlayerFile(suffix)` names it. Heard once for each join, for the
+    /// owner of an integrated server as for anyone else, on a server, with no
+    /// player's state swapped in. Not cancellable.
+    pub(super) fn native_player_load_from_file(
+        &mut self,
+        player: u128,
+        name: &str,
+        directory: &std::path::Path,
+    ) {
+        mod_api::dispatch_player_load_from_file(self, mod_api::mods(), player, name, directory);
+    }
+    /// A player's data was copied to their new player (NeoForge's
+    /// `PlayerEvent.Clone`, from `ServerPlayer.restoreFrom`): `was_death` is
+    /// true after a death, false when they left the End after the credits
+    /// (`respawn` with `keepAllPlayerData`). The uuid stays the same, so the
+    /// old and the new player share `player`. Heard before the new player is
+    /// placed, on a server, with no player's state swapped in. Not
+    /// cancellable.
+    pub(super) fn native_player_clone(&mut self, player: u128, name: &str, was_death: bool) {
+        mod_api::dispatch_player_clone(self, mod_api::mods(), player, name, was_death);
+    }
     /// The number of players with the mod container at `pos` of `dimension`
     /// open went from `previous` to `viewers` (vanilla's
     /// `ContainerOpenersCounter`, as a barrel keeps it): 0 to more than 0 is
@@ -5528,9 +5642,15 @@ impl Game<'_> {
     /// an arrival through a portal). `entity` is its ID and `kind` its type
     /// (`minecraft:item`). It is already in the level's lists, so helpers that
     /// take an entity ID find it. Set `canceled` to keep it out: it is taken
-    /// back out as if never added, and a `/summon` of it fails. 47 tells
-    /// item entities and experience orbs; later APIs add other kinds, so check
-    /// `kind`. Server-side.
+    /// back out as if never added, and a `/summon` of it fails. Tells every
+    /// kind in the game's entity lists (items, orbs, mobs, boats, minecarts,
+    /// armor stands, primed TNT, falling blocks, projectiles, rockets,
+    /// tridents), once each, in the order they were created; check `kind`. A
+    /// gameplay spawn is told when the next tick starts (a drop, an orb, a mob, a
+    /// `/summon` and a chunk's entities are told at once). A mod that
+    /// cancels one of the others sees it removed before it ticks again.
+    /// Not told: end crystals, the dragon, cushions, paintings, item frames and
+    /// the entities Horizon keeps without simulating. Server-side.
     pub(super) fn native_entity_join_level(
         &mut self,
         dimension: &str,
@@ -7540,6 +7660,8 @@ impl Game<'_> {
     }
     /// The mobs from index `from` on are new in the world.
     pub(super) fn native_mobs_joined(&mut self, from: usize, natural: bool) {
+        // A mod can keep a mob out; it is then taken out and not told of.
+        self.native_joins_flush(false, 0);
         for i in from..self.mobs.len() {
             let m = &self.mobs[i];
             let (kind, pos) = (mob_kind(m), [m.position.x, m.position.y, m.position.z]);
@@ -7620,34 +7742,6 @@ impl Game<'_> {
             .collect();
         self.native_entities_left("minecraft:experience_orb", &gone);
     }
-    /// `native_entity_join_level` for `entity`, just put at the end of its
-    /// list: false when a mod canceled, and the caller takes it back out.
-    /// A client of a server tells nothing.
-    pub(super) fn native_entity_joins(
-        &mut self,
-        entity: u32,
-        kind: &str,
-        pos: [f64; 3],
-        loaded_from_disk: bool,
-    ) -> bool {
-        if self.remote.is_some() {
-            return true;
-        }
-        let mut canceled = false;
-        let dimension = self.dim.id();
-        self.native_entity_join_level(
-            dimension,
-            entity,
-            kind,
-            pos,
-            loaded_from_disk,
-            &mut canceled,
-        );
-        if canceled {
-            self.persist.joins_canceled += 1;
-        }
-        !canceled
-    }
     /// The acting player's blow killed mob `index`.
     pub(super) fn native_kill_event(&mut self, index: usize) {
         let (entity, kind) = (self.mobs[index].id, mob_kind(&self.mobs[index]));
@@ -9083,9 +9177,12 @@ mod tests {
                 // split): horizon-mixins resolves the crate by its package.
                 format!("horizon_client_lib::crafting::native_{name}")
             } else if menu_hooks.contains(name) {
-                format!("horizon_client::menu::native_{name}")
+                // menu.rs compiles into horizon-client-lib (#5446's
+                // split): horizon-mixins resolves the crate by its package.
+                format!("horizon_client_lib::menu::native_{name}")
             } else if breath_hooks.contains(name) {
-                format!("horizon_client::breathing::native_{name}")
+                // breathing.rs compiles into horizon-client-lib too.
+                format!("horizon_client_lib::breathing::native_{name}")
             } else if level_hooks.contains(name) {
                 format!("horizon_client::game::native_hooks::GameLevel<'_>::native_{name}")
             } else {
@@ -9094,6 +9191,32 @@ mod tests {
             assert_eq!(hook["target"].as_str().unwrap(), target);
         }
         assert_eq!(names, declared);
+        // Every target's crate really compiles its module: #5446 moved
+        // files between horizon-client and horizon-client-lib, and a
+        // target left on the old crate applies to no bundle — the string
+        // comparison above shares its expectation with the catalog, so it
+        // alone cannot catch a move. The first path segment after the
+        // crate must be a module of that crate's lib root.
+        let client_root = include_str!("../lib.rs");
+        let lib_root = include_str!("../client_lib.rs");
+        for hook in &hooks {
+            let target = hook["target"].as_str().unwrap();
+            let (root, crate_name, rest) =
+                if let Some(rest) = target.strip_prefix("horizon_client::") {
+                    (client_root, "horizon_client", rest)
+                } else if let Some(rest) = target.strip_prefix("horizon_client_lib::") {
+                    (lib_root, "horizon_client_lib", rest)
+                } else {
+                    // The other crates (render, world) are their own packages,
+                    // never split.
+                    continue;
+                };
+            let module = rest.split("::").next().unwrap_or(rest);
+            assert!(
+                root.contains(&format!("mod {module};")),
+                "{crate_name} does not compile module `{module}` (target {target})"
+            );
+        }
     }
 
     /// The damage hook gets a mob's source from its damage: the causing mob,

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

@@ -297,6 +297,9 @@ impl Game<'_> {
             textures,
             cem,
             block_entity_shapes,
+            sounds,
+            ui_metadata,
+            language,
         } = staged;
         // Keep the working GPU resources, and hand its window surface over.
         if let Some(renderer) = &mut self.renderer {
@@ -396,10 +399,16 @@ impl Game<'_> {
             .write()
             .unwrap_or_else(std::sync::PoisonError::into_inner) =
             std::mem::take(&mut self.gui.atlas.blinks);
-        horizon_client::ui::load_metadata(&root);
-        lang::set(lang::Language::load(&[&root], &lang::code()));
+        horizon_client::ui::set_metadata(ui_metadata);
+        // Read with the language in use when the reload started: one picked since then wins.
+        let code = lang::code();
+        lang::set(if language.code == code {
+            language
+        } else {
+            lang::Language::load(&[&root], &code)
+        });
         self.refresh_remote_language();
-        self.audio.reload(&root);
+        self.audio.reload_with(&root, sounds);
         self.clear_lod();
         // A pack that may replace leaf models falls back to `Off` before the
         // reload marks every section dirty.
@@ -452,11 +461,27 @@ pub(super) fn stage_pack(
     progress.set(1);
     // The world's models and sprites and the GUI atlas read the same root and nothing of
     // each other: about a second each, side by side.
-    let (render, atlas, panorama) = std::thread::scope(|s| {
+    // The sound events, the GUI sprites' metadata and the language are read here too, not in
+    // the frame that applies the reload (about 20 ms of it).
+    let (render, atlas, panorama, (sounds, ui_metadata, language)) = std::thread::scope(|s| {
         let atlas =
             s.spawn(|| HudAtlas::build_over(&root, vanilla_root).map_err(|e| e.to_string()));
         let panorama = s.spawn(|| horizon_client::gfx::panorama::Faces::load(&root, vanilla_root));
-        (assets.reload(&root), atlas.join(), panorama.join())
+        let small = s.spawn(|| {
+            (
+                horizon_client::sound_events::SoundRegistry::load(&root),
+                horizon_client::ui::read_metadata(&root),
+                lang::Language::load(&[&root], &lang::code()),
+            )
+        });
+        (
+            assets.reload(&root),
+            atlas.join(),
+            panorama.join(),
+            small
+                .join()
+                .unwrap_or_else(|p| std::panic::resume_unwind(p)),
+        )
     });
     let render = Arc::new(render?);
     let mut atlas = atlas.unwrap_or_else(|p| std::panic::resume_unwind(p))?;
@@ -489,6 +514,9 @@ pub(super) fn stage_pack(
         textures,
         cem,
         block_entity_shapes,
+        sounds,
+        ui_metadata,
+        language,
     })
 }
 
@@ -503,6 +531,10 @@ pub(super) struct StagedPack {
     pub cem: Arc<horizon_client::mobs::cem::CemModels>,
     /// The block entities' models, the packs' custom entity models over vanilla's.
     pub block_entity_shapes: Arc<horizon_client::block_entity_render::BlockEntityShapes>,
+    /// The root's sound events, GUI sprite metadata and current language.
+    pub sounds: horizon_client::sound_events::SoundRegistry,
+    pub ui_metadata: horizon_client::ui::UiMetadata,
+    pub language: lang::Language,
 }
 
 /// `LoadingOverlay`'s stage lines for a pack reload, indexed by `progress`.

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

@@ -274,8 +274,13 @@ impl Game<'_> {
         }
         best
     }
-    /// `Painting.hurtServer` -> kill and `dropItem`.
-    pub(super) fn break_painting(&mut self, index: usize, by_player: bool) {
+    /// `Painting.hurtServer` -> kill and `dropItem`. False when a mod kept it
+    /// (`native_hanging_break`): it stays at `index`.
+    pub(super) fn break_painting(&mut self, index: usize, by_player: bool) -> bool {
+        let pos = self.paintings[index].pos;
+        if self.hanging_break_cancelled("minecraft:painting", pos, by_player) {
+            return false;
+        }
         let p = self.paintings.remove(index);
         let (lo, hi) = p.bounds();
         let at = [
@@ -285,12 +290,12 @@ impl Game<'_> {
         ];
         self.world.modified.insert((p.pos[0] >> 4, p.pos[2] >> 4));
         if !self.ui.rules.bool("entity_drops") {
-            return;
+            return true;
         }
         self.audio
             .play("minecraft:entity.painting.break", Some(at), 1.0, 1.0);
         if by_player && self.creative {
-            return;
+            return true;
         }
         // HangingEntity.spawnAtLocation: 0.15 out from the wall.
         let s = p.step().map(f64::from);
@@ -306,6 +311,7 @@ impl Game<'_> {
             [0.0; 3],
             10,
         );
+        true
     }
     /// BlockAttachedEntity.tick: check survival every 100 ticks.
     pub(super) fn tick_paintings(&mut self) {
@@ -323,8 +329,7 @@ impl Game<'_> {
             if self.paintings[i].check_interval >= 100 {
                 self.paintings[i].check_interval = 0;
                 let p = self.paintings[i].clone();
-                if !self.painting_survives(&p) {
-                    self.break_painting(i, false);
+                if !self.painting_survives(&p) && self.break_painting(i, false) {
                     continue;
                 }
             }

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

@@ -43,6 +43,8 @@ pub struct EntityMemory {
     /// Entities a native mod kept out of the level (`native_entity_join_level`),
     /// counted so `/summon` can fail as vanilla's refused add does.
     pub(super) joins_canceled: u32,
+    /// The highest entity id `native_entity_join_level` has been told of.
+    pub(super) joined_mark: u32,
 }
 
 /// The key that marks a compound queued with the chunk loads as a fresh add
@@ -342,6 +344,8 @@ impl Game<'_> {
                 let from_disk = !take_fresh(&mut tag);
                 // An End gateway's traveller never left the level: nothing joins.
                 let moved = take_moved(&mut tag);
+                // Whatever was added since the last tick joins before this one.
+                self.native_joins_flush(false, 0);
                 let kind = entity_nbt::kind(&tag).unwrap_or_default();
                 let uuid = entity_nbt::uuid(&tag);
                 if uuid.is_some_and(|u| self.restored_vehicle(u).is_some()) {
@@ -358,6 +362,8 @@ impl Game<'_> {
                         | "minecraft:snowball"
                         | "minecraft:egg"
                         | "minecraft:ender_pearl"
+                        | "minecraft:splash_potion"
+                        | "minecraft:lingering_potion"
                         | "minecraft:falling_block"
                         | "minecraft:firework_rocket"
                         | "minecraft:trident"
@@ -377,37 +383,19 @@ impl Game<'_> {
                         if let Some(e) =
                             entity_nbt::item_entity_from_nbt(&tag, self.next_entity, bob)
                         {
-                            let (id, p) = (e.id, e.position);
                             self.remember(e.id, uuid, tag);
                             self.dropped.push(e);
-                            if !moved
-                                && !self.native_entity_joins(
-                                    id,
-                                    "minecraft:item",
-                                    [p.x, p.y, p.z],
-                                    from_disk,
-                                )
-                            {
-                                self.dropped.pop();
-                                self.forget_entity(id);
-                            }
                         }
                     }
                     "minecraft:experience_orb" => {
                         for mut orb in entity_nbt::orbs_from_nbt(&tag) {
                             self.next_entity += 1;
                             orb.id = self.next_entity;
-                            let (id, p) = (orb.id, orb.position);
+                            let id = orb.id;
                             // An orb that came through a portal keeps its cooldown.
                             self.restore_portal_cooldown(id, &tag);
                             self.orbs.push(orb);
                             self.remember_tags(id, &tag);
-                            let kind = "minecraft:experience_orb";
-                            if !moved
-                                && !self.native_entity_joins(id, kind, [p.x, p.y, p.z], from_disk)
-                            {
-                                self.orbs.pop();
-                            }
                         }
                     }
                     "minecraft:arrow" => {
@@ -669,6 +657,13 @@ impl Game<'_> {
                     }
                     _ => self.persist.unknown.entry(key).or_default().push(tag),
                 }
+                // PersistentEntitySectionManager.addEntity: every kind that
+                // just joined tells the mods; a moved one does not join.
+                if moved {
+                    self.native_joins_skip();
+                } else {
+                    self.native_joins_flush(from_disk, 0);
+                }
             }
             self.native_entities_load(self.dim.id(), [key.0, key.1], count);
         }

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

@@ -603,7 +603,7 @@ impl Game<'_> {
         if let Some(mud) = self.pack.assets.registry.default_state("minecraft:mud") {
             self.level_set(pos, mud)?;
         }
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.swing_arm();
         Ok(true)
     }

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

@@ -56,7 +56,7 @@ impl Game<'_> {
             return Ok(());
         };
         self.world.modified.insert((pos[0] >> 4, pos[2] >> 4));
-        self.stats.add("used", "minecraft:bucket", 1);
+        self.award_stat("used", "minecraft:bucket", 1);
         if let Some(eye) = self
             .player
             .as_ref()

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

@@ -87,7 +87,7 @@ impl Game<'_> {
         }
         self.damage_held(1);
         self.post_block_game_event("minecraft:shear", pos, self.sculk_actor(), None);
-        self.stats.add("used", "minecraft:shears", 1);
+        self.award_stat("used", "minecraft:shears", 1);
         // ServerPlayerGameMode.useItemOn: the action was consumed.
         self.trigger_block("minecraft:item_used_on_block", pos, shears);
         Ok(true)

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

@@ -434,7 +434,7 @@ impl Game<'_> {
             .raids
             .create_or_extend(center, difficulty, amplifier, seed);
         if triggered {
-            self.stats.custom("raid_trigger", 1);
+            self.award_custom_stat("raid_trigger", 1);
             self.trigger_player("minecraft:voluntary_exile");
             self.native_raid_state_change(id, center, "triggered");
         }
@@ -660,7 +660,7 @@ impl Game<'_> {
                         EffectInstance::new("hero_of_the_village", raid::HERO_DURATION, amplifier);
                     effect.visible = false;
                     g.potions.effects.add(effect);
-                    g.stats.custom("raid_win", 1);
+                    g.award_custom_stat("raid_win", 1);
                     g.trigger_player("minecraft:hero_of_the_village");
                 }
             }),

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

@@ -6468,6 +6468,7 @@ impl Game<'_> {
         // collisions and the pull of the nearest player between the server's
         // updates; the server removes it on pickup.
         let (world, facts, collision) = (&self.world, self.res.facts(), self.collision);
+        let border = Some(self.border.geometry());
         let mut lava_random = None;
         let mut next_float = || {
             lava_random
@@ -6501,7 +6502,15 @@ impl Game<'_> {
                     l.steps -= 1;
                 }
                 let before = o.position;
-                let kept = o.tick(world, facts, collision, target, false, &mut next_float);
+                let kept = o.tick(
+                    world,
+                    facts,
+                    collision,
+                    target,
+                    false,
+                    &mut next_float,
+                    border,
+                );
                 // `tick` set `previous` to the stepped position: keep the
                 // pre-step one, as `xo` is in vanilla.
                 o.previous = old;
@@ -6519,11 +6528,12 @@ impl Game<'_> {
         // ItemEntity.tick runs on a client too: gravity, collisions and
         // friction move the item between the server's updates (every 20
         // ticks), and only the server removes it.
-        let (world, registry, facts, collision) = (
+        let (world, registry, facts, collision, border) = (
             &self.world,
             self.pack.assets.registry,
             self.res.facts(),
             self.collision,
+            Some(self.border.geometry()),
         );
         for d in self.dropped.iter_mut().filter(|_| running) {
             d.tick(
@@ -6535,6 +6545,7 @@ impl Game<'_> {
                 &self.res.motion().fluids,
                 // The server decides what an item rests on; this copy only moves between updates.
                 &[],
+                border,
             );
         }
         head_lerps.retain(|_, (_, steps)| *steps > 0);

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

@@ -611,16 +611,17 @@ impl Game<'_> {
         // fuse down (the swell and flash follow it) between the server's
         // updates (every 10 ticks), and a client discards it when the fuse
         // runs out; only the server explodes it.
-        let (world, collision, assets, facts, fluids) = (
+        let (world, collision, assets, facts, fluids, border) = (
             &self.world,
             self.collision,
             &self.pack.assets,
             self.res.facts(),
             &self.res.motion().fluids,
+            Some(self.border.geometry()),
         );
         self.tnts.retain_mut(|t| {
             // A fluid lookup that fails leaves it where its move put it.
-            let _ = t.tick(world, collision, assets, facts, fluids);
+            let _ = t.tick(world, collision, assets, facts, fluids, border);
             t.fuse > 0
         });
         // FallingBlockEntity.tick runs on a client too: the block falls by

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

@@ -71,7 +71,7 @@ impl Game<'_> {
             });
         } else {
             self.close_container();
-            self.stats.custom("leave_game", 1);
+            self.award_custom_stat("leave_game", 1);
             self.lan_close(false);
             self.free_player_beds()?;
             self.pending_save = Some(ClosingSave {

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

@@ -252,6 +252,12 @@ impl Game<'_> {
                     play.respawn_requested = false;
                     play.won_game = false;
                 }
+                // PlayerList.respawn(keepAllPlayerData = true), CHANGED_DIMENSION:
+                // PlayerEvent.Clone with `wasDeath` false.
+                if let Some(g) = host.hub.guest(conn) {
+                    let (uuid, name) = (g.uuid, g.name.clone());
+                    self.native_player_clone(uuid, &name, false);
+                }
                 self.start_server_trip(host, conn, Dim::Overworld, None);
                 self.portals.player.cooldown = 10;
             }

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

@@ -313,7 +313,7 @@ impl Game<'_> {
             self.sculk_actor(),
             Some(state),
         );
-        self.stats.add("used", &stack.item, 1);
+        self.award_stat("used", &stack.item, 1);
         self.consume_held();
         self.trigger_block("minecraft:item_used_on_block", pos, stack);
         true

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

@@ -255,7 +255,7 @@ impl Game<'_> {
         // itemAttackInteraction: hurtEnemy (statistic, wear), and the
         // post-attack enchantments when the target was hurt.
         if let Some(stack) = self.held().cloned() {
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
             if hurt {
                 self.post_attack(index);
             }
@@ -263,8 +263,7 @@ impl Game<'_> {
         }
         // damageStatsAndHearts.
         let actual = old_health - self.mobs[index].health;
-        self.stats
-            .custom("damage_dealt", (actual * 10.0).round() as i32);
+        self.award_custom_stat("damage_dealt", (actual * 10.0).round() as i32);
         if actual > 2.0 {
             let indicator = horizon_client::particles::ParticleOptions::simple(
                 horizon_client::particles::ParticleType::DamageIndicator,

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

@@ -562,7 +562,7 @@ impl Game<'_> {
             _ => "",
         };
         if !stat.is_empty() {
-            self.stats.custom(stat, 1);
+            self.award_custom_stat(stat, 1);
         }
         true
     }
@@ -1051,7 +1051,7 @@ impl Game<'_> {
             }
         }
         let pitch = self.world.random.next_float() * 0.1 + 0.9;
-        self.stats.custom("enchant_item", 1);
+        self.award_custom_stat("enchant_item", 1);
         self.trigger_enchanted_item(&enchanted_item, lapis_needed as i32);
         self.play_at("minecraft:block.enchantment_table.use", pos, 1.0, pitch);
         self.station_changed();

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

@@ -194,6 +194,30 @@ impl Game<'_> {
             self.stats.write(&path);
         }
     }
+    /// `ServerPlayer.awardStat`: `n` more of the statistic `ty` (a bare type
+    /// such as `used`) and `key`, unless a native mod cancels the award.
+    pub(super) fn award_stat(&mut self, ty: &str, key: &str, n: i32) {
+        // No mod, no name copied: the per-tick counters come through here.
+        let acting = if horizon_client::mod_api::mods().is_empty() {
+            None
+        } else {
+            self.lan_acting_uuid.zip(self.lan_acting_name.clone())
+        };
+        if let Some((player, name)) = acting {
+            let mut cancel = false;
+            namespaced(ty, |stat_type| {
+                self.native_player_stat_award(player, &name, stat_type, key, n, &mut cancel)
+            });
+            if cancel {
+                return;
+            }
+        }
+        self.stats.add(ty, key, n);
+    }
+    /// `Player.awardStat(Identifier)`: `n` more of the custom statistic `key`.
+    pub(super) fn award_custom_stat(&mut self, key: &str, n: i32) {
+        namespaced(key, |key| self.award_stat("custom", key, n));
+    }
     /// The per-tick counters (`Player.tick`/`ServerPlayer.tick` awardStat).
     pub(super) fn tick_stats(&mut self) {
         self.load_stats();
@@ -207,17 +231,16 @@ impl Game<'_> {
         };
         let alive = !p.health.dead_or_dying();
         let crouching = p.pose == horizon_client::pose::Pose::Crouching;
-        let s = &mut self.stats;
-        s.custom("play_time", 1);
-        s.custom("total_world_time", 1);
+        self.award_custom_stat("play_time", 1);
+        self.award_custom_stat("total_world_time", 1);
         if alive {
-            s.custom("time_since_death", 1);
+            self.award_custom_stat("time_since_death", 1);
             if !sleeping {
-                s.custom("time_since_rest", 1);
+                self.award_custom_stat("time_since_rest", 1);
             }
         }
         if crouching {
-            s.custom("sneak_time", 1);
+            self.award_custom_stat("sneak_time", 1);
         }
     }
     fn tick_movement_stats(&mut self) {
@@ -269,51 +292,58 @@ impl Game<'_> {
                 .map(|m| m.species())
                 .ok_or(())
         });
-        let s = &mut self.stats;
         match riding {
             Some(Ok(sp)) => {
                 use horizon_client::mobs::Species;
                 // `checkRidingStatistics`: only these mounts count, the horse
                 // family by the full 3D distance; any other mount nothing.
                 match sp {
-                    Species::Pig => s.custom("pig_one_cm", total),
-                    Species::Strider => s.custom("strider_one_cm", total),
-                    Species::HappyGhast => s.custom("happy_ghast_one_cm", total),
+                    Species::Pig => self.award_custom_stat("pig_one_cm", total),
+                    Species::Strider => self.award_custom_stat("strider_one_cm", total),
+                    Species::HappyGhast => self.award_custom_stat("happy_ghast_one_cm", total),
                     Species::Nautilus | Species::ZombieNautilus => {
-                        s.custom("nautilus_one_cm", total)
+                        self.award_custom_stat("nautilus_one_cm", total)
                     }
                     sp if horizon_client::mobs::equine::is_equine(sp) => {
-                        s.custom("horse_one_cm", total)
+                        self.award_custom_stat("horse_one_cm", total)
                     }
                     _ => {}
                 }
             }
             Some(Err(())) => {
                 if self.boats.iter().any(|b| Some(b.id) == self.riding) {
-                    s.custom("boat_one_cm", total)
+                    self.award_custom_stat("boat_one_cm", total)
                 } else if self.carts.iter().any(|c| Some(c.id) == self.riding) {
-                    s.custom("minecart_one_cm", total)
+                    self.award_custom_stat("minecart_one_cm", total)
                 }
             }
-            None if swimming => s.custom("swim_one_cm", total),
+            None if swimming => self.award_custom_stat("swim_one_cm", total),
             None if eye_in_water.fluid == horizon_client::blocks::Fluid::Water => {
-                s.custom("walk_under_water_one_cm", total)
+                self.award_custom_stat("walk_under_water_one_cm", total)
             }
-            None if in_water => s.custom("walk_on_water_one_cm", horizontal),
-            None if climbing => s.custom("climb_one_cm", (d.y * 100.0).round() as i32),
-            None if on_ground => {
-                if sprinting {
-                    s.custom("sprint_one_cm", horizontal)
-                } else if crouching {
-                    s.custom("crouch_one_cm", horizontal)
-                } else {
-                    s.custom("walk_one_cm", horizontal)
+            None if in_water => {
+                if horizontal > 0 {
+                    self.award_custom_stat("walk_on_water_one_cm", horizontal)
                 }
             }
-            None if gliding => s.custom("aviate_one_cm", total),
+            None if climbing => {
+                self.award_custom_stat("climb_one_cm", (d.y * 100.0).round() as i32)
+            }
+            None if on_ground => {
+                if horizontal > 0 {
+                    if sprinting {
+                        self.award_custom_stat("sprint_one_cm", horizontal)
+                    } else if crouching {
+                        self.award_custom_stat("crouch_one_cm", horizontal)
+                    } else {
+                        self.award_custom_stat("walk_one_cm", horizontal)
+                    }
+                }
+            }
+            None if gliding => self.award_custom_stat("aviate_one_cm", total),
             // Airborne and not gliding: more than 25 cm sideways per move
             // (creative flight, or a long jump), not only flying.
-            None if horizontal > 25 => s.custom("fly_one_cm", horizontal),
+            None if horizontal > 25 => self.award_custom_stat("fly_one_cm", horizontal),
             None => {}
         }
     }

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

@@ -50,17 +50,20 @@ impl PrimedTnt {
         assets: &horizon_client::assets::Assets,
         facts: &horizon_client::blocks::BlockFacts,
         fluids: &horizon_client::motion::FluidResources,
+        border: Option<&horizon_core::geometry::border::BorderGeometry>,
     ) -> Result<Vec<BlockPos>> {
         self.previous = self.position;
         self.velocity.y -= self.get_gravity();
-        let mut scene = SceneCollisions {
+        let scene = SceneCollisions {
             world,
             binding: collision,
             subject: None,
         };
         let wanted = self.velocity;
+        // Entity.collide: the world border's walls stop it too.
+        let border = border.map(|b| (b, [self.position.x, self.position.z]));
         let moved = scene
-            .resolve(self.bounds(), wanted, 0.0, self.on_ground)
+            .resolve_in_border(self.bounds(), wanted, 0.0, self.on_ground, border)
             .unwrap_or(Vec3::ZERO);
         if horizon_client::entities::move_applies(wanted, moved) {
             self.position = Vec3::new(
@@ -246,6 +249,7 @@ impl Game<'_> {
                 &self.pack.assets,
                 self.res.facts(),
                 &self.res.motion().fluids,
+                Some(self.border.geometry()),
             )?;
             for pos in tops {
                 self.bubble_column_particles(pos);
@@ -541,6 +545,55 @@ mod tests {
         assert!(!tnt.on_ground);
     }
 
+    /// `Entity.collectColliders` (#7080): the world border's wall stops primed
+    /// TNT. A border of size 10 around (20, 20) has its east wall at x = 25;
+    /// the TNT starts at x = 24 on the test scene's flat ground, 1.5 east.
+    #[test]
+    fn the_world_border_stops_primed_tnt() {
+        let root = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("../../.local/horizon-client")
+            .join(horizon_core::VANILLA_VERSION);
+        if !root.join("movement-properties.nbt").exists() {
+            return;
+        }
+        let assets = horizon_client::assets::Assets::load(&root).unwrap();
+        let render = assets.reload(&root).unwrap();
+        let facts = horizon_client::blocks::BlockFacts::load(&root, assets.registry).unwrap();
+        let fluids = horizon_client::motion::FluidResources::new(&assets, &facts).unwrap();
+        let collision = horizon_client::collisions::load(&root, assets.registry).unwrap();
+        let world = horizon_client::world::World::test_scene(&assets, &render, 3).unwrap();
+        let border =
+            horizon_core::geometry::border::BorderGeometry::new([20.0, 20.0], 10.0, 29_999_984)
+                .unwrap();
+        for bordered in [false, true] {
+            let at = Vec3::new(24.0, 4.0, 20.5);
+            let mut tnt = PrimedTnt {
+                no_gravity: false,
+                id: 0,
+                position: at,
+                previous: at,
+                velocity: Vec3::new(1.5, 0.0, 0.0),
+                fuse: 80,
+                on_ground: true,
+                owner: None,
+                guest: None,
+                power: 4.0,
+            };
+            let border = bordered.then_some(&border);
+            tnt.tick(&world, &collision, &assets, &facts, &fluids, border)
+                .unwrap();
+            let east = tnt.bounds().max_position().x;
+            if bordered {
+                assert!(
+                    (east - 25.0).abs() < 1.0e-7,
+                    "stops on the wall, got {east}"
+                );
+            } else {
+                assert!(east > 25.0, "no border: goes on, got {east}");
+            }
+        }
+    }
+
     #[test]
     fn primed_tnt_follows_water_currents_after_moving() {
         let root = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
@@ -580,7 +633,7 @@ mod tests {
             guest: None,
             power: 4.0,
         };
-        tnt.tick(&world, &collision, &assets, &facts, &fluids)
+        tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
             .unwrap();
         assert_eq!(
             tnt.position.x, at.x,
@@ -592,14 +645,14 @@ mod tests {
             tnt.velocity
         );
         assert_eq!(tnt.fuse, 79);
-        tnt.tick(&world, &collision, &assets, &facts, &fluids)
+        tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
             .unwrap();
         assert!((tnt.position.x - at.x - 0.014).abs() < 1e-12);
         assert!(tnt.on_ground);
         tnt.position = at;
         tnt.velocity = Vec3::ZERO;
         tnt.fuse = 1;
-        tnt.tick(&world, &collision, &assets, &facts, &fluids)
+        tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
             .unwrap();
         assert_eq!(tnt.fuse, 0);
         assert_eq!(
@@ -610,7 +663,7 @@ mod tests {
         tnt.position = at;
         tnt.velocity = Vec3::ZERO;
         tnt.fuse = 80;
-        tnt.tick(&world, &collision, &assets, &facts, &fluids)
+        tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
             .unwrap();
         assert_eq!(
             tnt.velocity.x, 0.0,
@@ -626,7 +679,7 @@ mod tests {
             .unwrap();
         tnt.on_ground = false;
         tnt.velocity = Vec3::ZERO;
-        tnt.tick(&world, &collision, &assets, &facts, &fluids)
+        tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
             .unwrap();
         assert!(
             tnt.position.y < at.y && tnt.velocity.y < 0.0,
@@ -683,7 +736,7 @@ mod tests {
             power: 4.0,
         };
         for _ in 0..10 {
-            tnt.tick(&world, &collision, &assets, &facts, &fluids)
+            tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
                 .unwrap();
         }
         assert!(
@@ -704,7 +757,7 @@ mod tests {
         tnt.velocity = Vec3::ZERO;
         tnt.on_ground = false;
         for _ in 0..4 {
-            tnt.tick(&world, &collision, &assets, &facts, &fluids)
+            tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
                 .unwrap();
         }
         assert!(
@@ -764,7 +817,7 @@ mod tests {
         let mut tnt = primed();
         for _ in 0..30 {
             tops.extend(
-                tnt.tick(&world, &collision, &assets, &facts, &fluids)
+                tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
                     .unwrap(),
             );
         }
@@ -778,7 +831,7 @@ mod tests {
         let mut tnt = primed();
         for _ in 0..10 {
             assert!(
-                tnt.tick(&world, &collision, &assets, &facts, &fluids)
+                tnt.tick(&world, &collision, &assets, &facts, &fluids, None)
                     .unwrap()
                     .is_empty()
             );

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

@@ -59,7 +59,7 @@ impl Game<'_> {
                 *cell = None;
             }
         }
-        self.stats.add("used", TOTEM, 1);
+        self.award_stat("used", TOTEM, 1);
         self.trigger_item(
             "minecraft:used_totem",
             &horizon_client::items::ItemStack::new(TOTEM, 1),

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

@@ -251,7 +251,7 @@ impl Game<'_> {
             self.handle_mob_events(events)?;
             return Ok(true);
         }
-        self.stats.custom("talked_to_villager", 1);
+        self.award_custom_stat("talked_to_villager", 1);
         self.ensure_offers(index);
         let m = &self.mobs[index];
         let trade = m.extra.trade.as_deref().cloned().unwrap_or_default();
@@ -470,7 +470,7 @@ impl Game<'_> {
     /// for a server's player (when the trader is still in the level).
     pub(super) fn merchant_traded(&mut self, mob: Option<u32>, offers: &[MerchantOffer]) {
         for offer in offers {
-            self.stats.custom("traded_with_villager", 1);
+            self.award_custom_stat("traded_with_villager", 1);
             let merchant = mob.and_then(|id| self.mobs.iter().find(|m| m.id == id));
             let kind = merchant.map(super::native_hooks::mob_kind);
             let villager = merchant.map(|m| self.mob_entity(m));

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

@@ -167,7 +167,7 @@ impl Game<'_> {
         };
         if taken > 0 {
             // awardStat(ITEM_USED), then stackToInsert.consume(count, player).
-            self.stats.add("used", &stack.item, 1);
+            self.award_stat("used", &stack.item, 1);
             for _ in 0..taken {
                 self.consume_held();
             }

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

@@ -75,7 +75,7 @@ impl Game<'_> {
         let pitch = 0.4 / (self.world.random.next_float() * 0.4 + 0.8);
         self.audio
             .play("minecraft:entity.wind_charge.throw", Some(eye), 0.5, pitch);
-        self.stats.add("used", "minecraft:wind_charge", 1);
+        self.award_stat("used", "minecraft:wind_charge", 1);
         self.swing_arm();
         if !self.creative
             && let Some(s) = self.held_mut().as_mut()

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

@@ -35,6 +35,13 @@ pub struct ServerAdvancements {
 pub struct FirstTick {
     pub recipe_book_add: Option<Vec<u8>>,
     pub update_advancements: Vec<u8>,
+    pub granted: Vec<CriterionGrant>,
+}
+
+/// A criterion `CriteriaTriggers.TICK` newly granted, for the game to tell the mods.
+pub struct CriterionGrant {
+    pub advancement: String,
+    pub criterion: String,
 }
 
 impl ServerAdvancements {
@@ -89,9 +96,15 @@ impl ServerAdvancements {
             })
             .collect();
         let date = crate::advancements::date_text(now_millis.div_euclid(1000));
+        let mut granted = Vec::new();
         for (a, got) in self.tree.list.iter().zip(&obtained) {
             for c in got {
-                progress.grant(&a.id, c, &date);
+                if progress.grant(&a.id, c, &date) {
+                    granted.push(CriterionGrant {
+                        advancement: a.id.clone(),
+                        criterion: (*c).to_owned(),
+                    });
+                }
             }
         }
         // AdvancementRewards.grant: the recipes, in the advancements' order.
@@ -126,6 +139,7 @@ impl ServerAdvancements {
         FirstTick {
             recipe_book_add,
             update_advancements: w.data,
+            granted,
         }
     }
 
@@ -135,13 +149,15 @@ impl ServerAdvancements {
     /// drops a criterion it lost), the next `flushDirty` is a first packet
     /// again, and the next `CriteriaTriggers.TICK` meets the new tree's
     /// `minecraft:tick` criteria, rewarding the recipes of the advancements
-    /// that complete. Returns the recipe book packet those recipes need.
+    /// that complete. The criteria it grants are added to `granted`. Returns
+    /// the recipe book packet those recipes need.
     pub fn reload(
         &self,
         sync: &SyncData,
         now_millis: i64,
         progress: &mut Progress,
         book: &mut Settings,
+        granted: &mut Vec<CriterionGrant>,
     ) -> Option<Vec<u8>> {
         let by_id: HashMap<&str, &crate::advancements::Advancement> =
             self.tree.list.iter().map(|a| (a.id.as_str(), a)).collect();
@@ -159,8 +175,14 @@ impl ServerAdvancements {
         for a in &self.tree.list {
             let was_done = progress.done(a);
             for c in &a.criteria {
-                if c.trigger == "minecraft:tick" && c.conditions.is_null() {
-                    progress.grant(&a.id, &c.name, &date);
+                if c.trigger == "minecraft:tick"
+                    && c.conditions.is_null()
+                    && progress.grant(&a.id, &c.name, &date)
+                {
+                    granted.push(CriterionGrant {
+                        advancement: a.id.clone(),
+                        criterion: c.name.clone(),
+                    });
                 }
             }
             if !was_done && progress.done(a) {

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

@@ -175,6 +175,13 @@ pub enum HostEvent {
     },
 }
 
+/// The criteria `CriteriaTriggers.TICK` granted one player.
+pub struct TickGrants {
+    pub player: u128,
+    pub name: String,
+    pub grants: Vec<super::advancements::CriterionGrant>,
+}
+
 /// What one player started and stopped tracking, in order, for the game to
 /// tell the mods.
 pub struct TrackingBatch {
@@ -201,6 +208,9 @@ pub struct Hub {
     /// The entities players started and stopped tracking, collected by
     /// `collect_tracking`, for the game to tell the mods.
     pub native_tracking: Vec<TrackingBatch>,
+    /// Criteria `CriteriaTriggers.TICK` granted to players, for the game to
+    /// tell the mods.
+    pub native_advancement_grants: Vec<TickGrants>,
     /// Players a native mod hid (`native_hide_player`), by UUID, on or off:
     /// only players of at least that permission level see them, in the
     /// player list, the world and their joining and leaving.
@@ -547,6 +557,7 @@ impl Hub {
             mod_commands: (serde_json::Value::Null, None),
             native_menu_events: Vec::new(),
             native_tracking: Vec::new(),
+            native_advancement_grants: Vec::new(),
             hidden: Default::default(),
             teams: Vec::new(),
             nicknames: std::collections::HashMap::new(),
@@ -2610,6 +2621,11 @@ impl Hub {
                     g.send(&raw(ids::RECIPE_BOOK_ADD, add));
                 }
                 g.send(&raw(ids::UPDATE_ADVANCEMENTS, first.update_advancements));
+                self.native_advancement_grants.push(TickGrants {
+                    player: g.uuid,
+                    name: g.name.clone(),
+                    grants: first.granted,
+                });
                 g.advancements_visible = sync.advancements.visibility(&g.advancements);
                 g.advancements_changed.clear();
             } else {
@@ -2744,6 +2760,7 @@ impl Hub {
             .duration_since(std::time::UNIX_EPOCH)
             .map_or(0, |d| d.as_millis() as i64);
         for g in &mut self.guests {
+            let mut granted = Vec::new();
             // PlayerAdvancements.reload: isFirstPacket again, the progress
             // read against the new tree; a player whose advancements were
             // never loaded does that on their first tick.
@@ -2752,12 +2769,20 @@ impl Hub {
             }
             g.advancements_visible.clear();
             g.advancements_changed.clear();
-            if let Some(add) =
-                sync.advancements
-                    .reload(&sync, now, &mut g.advancements, &mut g.recipe_book)
-            {
+            if let Some(add) = sync.advancements.reload(
+                &sync,
+                now,
+                &mut g.advancements,
+                &mut g.recipe_book,
+                &mut granted,
+            ) {
                 g.send(&raw(ids::RECIPE_BOOK_ADD, add));
             }
+            self.native_advancement_grants.push(TickGrants {
+                player: g.uuid,
+                name: g.name.clone(),
+                grants: granted,
+            });
         }
         // broadcastAll(ClientboundUpdateTagsPacket).
         self.broadcast(&C::UpdateTags(sync.tags.clone()));

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

@@ -15,11 +15,22 @@ use std::{
     sync::Arc,
 };
 
+/// `PlayerDataStorage`'s player directory (`players/data`), created on first use
+/// as its constructor does with `mkdirs`.
+pub fn directory(world: &Path) -> PathBuf {
+    let dir = directory_path(world);
+    if let Err(e) = std::fs::create_dir_all(&dir) {
+        log::warn!("Horizon: {} is not created: {e}", dir.display());
+    }
+    dir
+}
+
+fn directory_path(world: &Path) -> PathBuf {
+    world.join("players").join("data")
+}
+
 pub fn path(world: &Path, uuid: u128) -> PathBuf {
-    world
-        .join("players")
-        .join("data")
-        .join(format!("{}.dat", uuid_string(uuid)))
+    directory_path(world).join(format!("{}.dat", uuid_string(uuid)))
 }
 
 /// `UUIDUtil.uuidToIntArray`.

crates/horizon-client/src/mobs.rs

@@ -957,6 +957,10 @@ pub struct Extra {
     pub swing_stab: bool,
     pub flag: bool,
     pub flag2: bool,
+    /// `AbstractHorse`'s `Bred` save flag: nothing sets it at runtime (no
+    /// vanilla code calls `setBred` outside `readAdditionalSaveData`), so only
+    /// a save or `/summon` gives it, and `followMommy` reads it.
+    pub bred: bool,
     /// `AbstractHorse.allowStandSliding`: the rider's jump sets it, and a
     /// horse still rearing then goes on with the rider's keys until the rear
     /// ends (`tick` clears it).
@@ -1534,6 +1538,16 @@ pub enum MobEvent {
         amount: f32,
         source: Damage,
     },
+    /// `Pufferfish.touch` on a mob (`Pufferfish.aiStep`): the hit, then, only
+    /// when `hurtServer` let it land, the fish's `entity.puffer_fish.sting`
+    /// and the poison it gives (`poison_ticks`, `60 * getPuffState()`).
+    PufferfishSting {
+        mob: u32,
+        target: u32,
+        amount: f32,
+        source: Damage,
+        poison_ticks: i32,
+    },
     /// `LivingEntity.stabAttack`'s `target.stopRiding()`: a spear knocks the
     /// target off its mount.
     StabDismount {
@@ -1944,6 +1958,8 @@ pub struct Seen {
     pub baby: bool,
     pub in_love: bool,
     pub tame: bool,
+    /// `AbstractHorse.isBred`: the `Bred` flag (`followMommy` reads it).
+    pub bred: bool,
     /// A tamed animal's owner (`getOwner`).
     pub owner: Option<[i32; 4]>,
     pub hostile: bool,
@@ -2145,6 +2161,7 @@ impl Mob {
                 m.extra.in_love > 0
             },
             tame: m.extra.tame,
+            bred: m.extra.bred,
             owner: m.extra.owner,
             hostile: m.hostile(),
             target: m.ai.target,

crates/horizon-client/src/mobs/aquatic.rs

@@ -2,7 +2,7 @@
 //! tropical fish and pufferfish (`AbstractFish`, puffing), and dolphins
 //! (breathing, smooth swimming).
 use super::{
-    Mob, MobEvent, MobWorld, Species,
+    Damage, Mob, MobEvent, MobWorld, Species, Who,
     anim::{Poses, State},
     control::MoveKind,
     goals::{
@@ -333,6 +333,9 @@ pub fn ai_step(m: &mut Mob, w: &MobWorld, events: &mut Vec<MobEvent>) {
                     m.sound("entity.puffer_fish.sting", events);
                 }
             }
+            if m.species() == S::Pufferfish {
+                sting_touching_mobs(m, w, events);
+            }
         }
         S::Dolphin => {
             // Dolphin.tick: moisture out of water, hop on land.
@@ -364,6 +367,65 @@ pub fn ai_step(m: &mut Mob, w: &MobWorld, events: &mut Vec<MobEvent>) {
         _ => {}
     }
 }
+
+/// `EntityTypeTags.NOT_SCARY_FOR_PUFFERFISH`: the mobs a pufferfish leaves
+/// alone, its own kind and the water mobs it shares a tank with.
+pub fn not_scary_for_pufferfish(s: Species) -> bool {
+    matches!(
+        s,
+        Species::Cod
+            | Species::Salmon
+            | Species::TropicalFish
+            | Species::Pufferfish
+            | Species::Squid
+            | Species::GlowSquid
+            | Species::Dolphin
+            | Species::Turtle
+            | Species::Guardian
+            | Species::ElderGuardian
+            | Species::Tadpole
+            | Species::Nautilus
+            | Species::ZombieNautilus
+            | Species::SulfurCube
+    )
+}
+
+/// `Pufferfish.aiStep` after `AbstractFish.aiStep`: a puffed pufferfish stings
+/// every mob that touches it, not only the player. The query is `Mob.class`
+/// in its own box inflated by 0.3, filtered by `TARGETING_CONDITIONS` (alive
+/// and not `#not_scary_for_pufferfish`; invisibility and line of sight are
+/// not tested), and each one takes `Pufferfish.touch`: `doTeamsAllowDamage`,
+/// then a `mobAttack` hit for `getPuffState() + 1`. The poison and the sting
+/// sound follow a hit that landed, which only the game layer knows.
+fn sting_touching_mobs(m: &mut Mob, w: &MobWorld, events: &mut Vec<MobEvent>) {
+    if !m.alive() || m.extra.size <= 0 {
+        return;
+    }
+    let area = m.bounds().inflate(Vec3::new(0.3, 0.3, 0.3));
+    let own = w.teams.of(Who::Mob(m.id));
+    let stung: Vec<u32> = w
+        .others_near(area)
+        .filter(|o| {
+            o.id != m.id
+                && o.alive
+                && !not_scary_for_pufferfish(o.species)
+                && o.bounds.intersects(area)
+                && crate::scoreboard::teams_allow_damage(own, w.teams.of(Who::Mob(o.id)))
+        })
+        .map(|o| o.id)
+        .collect();
+    let from = [m.position.x, m.position.y, m.position.z];
+    for target in stung {
+        events.push(MobEvent::PufferfishSting {
+            mob: m.id,
+            target,
+            amount: 1.0 + m.extra.size as f32,
+            source: Damage::mob(m.id, from),
+            poison_ticks: 60 * m.extra.size,
+        });
+    }
+}
+
 /// Squid.aiStep: tentacle cycle, propulsion and body rotation.
 fn squid_ai_step(m: &mut Mob) {
     squid_step(m, false);
@@ -881,23 +943,7 @@ impl Goal for PufferfishPuff {
         let mob = cx.w.others_near(area).any(|s| {
             s.id != m.id
                 && s.alive
-                && !matches!(
-                    s.species,
-                    Species::Cod
-                        | Species::Salmon
-                        | Species::TropicalFish
-                        | Species::Pufferfish
-                        | Species::Squid
-                        | Species::GlowSquid
-                        | Species::Dolphin
-                        | Species::Turtle
-                        | Species::Guardian
-                        | Species::ElderGuardian
-                        | Species::Tadpole
-                        | Species::Nautilus
-                        | Species::ZombieNautilus
-                        | Species::SulfurCube
-                )
+                && !not_scary_for_pufferfish(s.species)
                 && area.intersects(s.bounds)
         });
         player || mob
@@ -1099,3 +1145,85 @@ mod school_tests {
         assert!((100..=110).contains(&start));
     }
 }
+
+#[cfg(test)]
+mod pufferfish_sting_tests {
+    use super::*;
+    use crate::mobs::world::with_test_world;
+    use std::sync::Arc;
+
+    /// What a pufferfish puffed to `puff` stings in one `ai_step`, as
+    /// `(target, damage)`, with `others` standing `x` blocks east of it.
+    fn stings(puff: i32, others: &[(&str, f64)]) -> Option<Vec<(u32, f32)>> {
+        let mut built = None;
+        with_test_world(&[], |_, types| {
+            let mob = |id: u32, name: &str, at: Vec3| {
+                Mob::new(id, Arc::new(types.types[name].clone()), at, 0.0)
+            };
+            let mut fish = mob(1, "minecraft:pufferfish", Vec3::new(0.5, 64.0, 0.5));
+            fish.extra.size = puff;
+            let seen: Vec<_> = others
+                .iter()
+                .enumerate()
+                .map(|(i, (name, x))| {
+                    mob(i as u32 + 2, name, Vec3::new(0.5 + x, 64.0, 0.5)).seen(None)
+                })
+                .collect();
+            built = Some((fish, seen));
+        });
+        let (mut fish, seen) = built?;
+        let mut events = Vec::new();
+        with_test_world(&seen, |w, _| ai_step(&mut fish, w, &mut events));
+        Some(
+            events
+                .iter()
+                .filter_map(|e| match e {
+                    MobEvent::PufferfishSting {
+                        mob: 1,
+                        target,
+                        amount,
+                        source,
+                        poison_ticks,
+                    } => {
+                        assert_eq!(source.attacker, Some(Who::Mob(1)));
+                        assert_eq!(
+                            *poison_ticks,
+                            60 * puff,
+                            "Pufferfish.touch's POISON lasts 60 * getPuffState()"
+                        );
+                        Some((*target, *amount))
+                    }
+                    _ => None,
+                })
+                .collect(),
+        )
+    }
+
+    /// `Pufferfish.aiStep`: a puffed pufferfish stings every mob whose box
+    /// meets its own (inflated by 0.3), not only the player, for
+    /// `getPuffState() + 1`.
+    #[test]
+    fn a_puffed_pufferfish_stings_the_mobs_that_touch_it() {
+        let Some(half) = stings(1, &[("minecraft:zombie", 0.5)]) else {
+            return;
+        };
+        assert_eq!(half, vec![(2, 2.0)], "puff state 1 stings for 1 + 1");
+        let full = stings(2, &[("minecraft:zombie", 0.5)]).unwrap();
+        assert_eq!(full, vec![(2, 3.0)], "puff state 2 stings for 1 + 2");
+        assert!(
+            stings(0, &[("minecraft:zombie", 0.5)]).unwrap().is_empty(),
+            "a deflated pufferfish stings nobody"
+        );
+        assert!(
+            stings(2, &[("minecraft:zombie", 1.5)]).unwrap().is_empty(),
+            "a zombie a block away never touches it"
+        );
+        // `#not_scary_for_pufferfish`: its tank mates are left alone.
+        assert!(
+            stings(2, &[("minecraft:cod", 0.4), ("minecraft:squid", 0.3)])
+                .unwrap()
+                .is_empty(),
+            "a cod and a squid are not scary"
+        );
+    }
+}

crates/horizon-client/src/mobs/equine.rs

@@ -10,6 +10,7 @@ use super::{
         Tempt, goal_clone,
     },
 };
+use horizon_core::geometry::Vec3;
 use horizon_core::geometry::trig::Mth;
 use horizon_core::random::RandomSource;
 use std::f32::consts::PI;
@@ -740,9 +741,13 @@ pub fn tail_tick(m: &mut Mob) {
 /// eating/standing/mouth animations.
 pub fn ai_step(m: &mut Mob, w: &MobWorld, events: &mut Vec<MobEvent>) {
     if super::camel::is_camel(m.species()) {
+        // Camel.aiStep runs AbstractHorse.aiStep first, and its followMommy is
+        // the last thing that does.
+        follow_mommy(m, w);
         return super::camel::ai_step(m, events);
     }
     if super::llama::is_llama(m.species()) {
+        follow_mommy(m, w);
         return super::llama::ai_step(m, w);
     }
     if m.alive() && m.random.next_int_bound(900).unwrap_or(1) == 0 && m.death_time == 0 {
@@ -772,6 +777,46 @@ pub fn ai_step(m: &mut Mob, w: &MobWorld, events: &mut Vec<MobEvent>) {
     }
     stand_tick(m);
     animate(m);
+    follow_mommy(m, w);
+}
+
+/// `AbstractHorse.aiStep`'s last call, `followMommy`: a bred foal that is not
+/// eating keeps a path to the nearest bred `AbstractHorse` within 16 blocks
+/// while it is more than two blocks away (`MOMMY_TARGETING`, and
+/// `this.distanceToSqr(mommy) > 4.0`). `PathNavigation.createPath(entity, 0)`
+/// installs that path and leaves the navigation's speed modifier alone, so the
+/// foal walks it at whatever speed its goals last asked for.
+pub fn follow_mommy(m: &mut Mob, w: &MobWorld) {
+    if !m.extra.bred || !m.is_baby() || m.extra.flag {
+        return;
+    }
+    let at = m.position;
+    // `MOMMY_TARGETING`'s range is 16 from the foal's position, and the search
+    // box is its own bounding box inflated by the same 16.
+    let area = m.bounds().inflate(Vec3::new(16.0, 16.0, 16.0));
+    let mommy = w
+        .others_near(area)
+        .filter(|o| {
+            o.alive
+                && o.bred
+                && is_equine(o.species)
+                && area.intersects(o.bounds)
+                && at.distance_squared(o.position) <= 256.0
+        })
+        .min_by(|a, b| {
+            at.distance_squared(a.position)
+                .total_cmp(&at.distance_squared(b.position))
+        })
+        .map(|o| o.position);
+    let Some(mommy) = mommy else {
+        return;
+    };
+    if at.distance_squared(mommy) <= 4.0 {
+        return;
+    }
+    let speed = m.ai.nav.speed_modifier;
+    let path = m.create_path_to_entity(w, [mommy.x, mommy.y, mommy.z], 0);
+    m.nav_move_to_path(w, path, speed);
 }
 /// `AbstractHorse.tick`: the stand counter runs down to `clearStanding`. It is
 /// in `tick`, not `aiStep`, so a horse with no AI stops rearing too.
@@ -1107,3 +1152,143 @@ mod tests {
         assert_eq!(swim_volume(&horse, 0.35), 0.35);
     }
 }
+
+#[cfg(test)]
+mod follow_mommy_tests {
+    use super::*;
+    use crate::mobs::world::{with_built_test_world, with_test_world};
+    use std::sync::Arc;
+
+    /// The block the foal's navigation path ends on after one `ai_step`, with
+    /// the foal at x = 0.5 on a stone floor and `others` (name, x, bred)
+    /// standing on the same floor.
+    fn target_pos(
+        foal: (bool, bool, bool),
+        others: &[(&str, f64, bool)],
+    ) -> Option<Option<[i32; 3]>> {
+        let (bred, baby, eating) = foal;
+        let mut built = None;
+        with_test_world(&[], |_, types| {
+            let mob = |id: u32, name: &str, at: Vec3| {
+                let mut m = Mob::new(id, Arc::new(types.types[name].clone()), at, 0.0);
+                m.on_ground = true;
+                m
+            };
+            let seen: Vec<_> = others
+                .iter()
+                .enumerate()
+                .map(|(i, (name, x, bred))| {
+                    let mut m = mob(i as u32 + 2, name, Vec3::new(*x, 1.0, 0.5));
+                    m.extra.bred = *bred;
+                    m.seen(None)
+                })
+                .collect();
+            let mut foal = mob(1, "minecraft:horse", Vec3::new(0.5, 1.0, 0.5));
+            foal.extra.bred = bred;
+            foal.extra.age = if baby { -24_000 } else { 0 };
+            foal.extra.flag = eating;
+            built = Some((foal, seen));
+        });
+        let (mut foal, seen) = built?;
+        let mut out = None;
+        with_built_test_world(
+            &seen,
+            |world, registry| {
+                // The chunks the pathfinder looks through, over a stone floor.
+                for (cx, cz) in [
+                    (-1, -1),
+                    (-1, 0),
+                    (-1, 1),
+                    (0, -1),
+                    (0, 0),
+                    (0, 1),
+                    (1, -1),
+                    (1, 0),
+                    (1, 1),
+                ] {
+                    world
+                        .chunks
+                        .insert((cx, cz), Arc::new(crate::chunk::Chunk::empty(cx, cz)));
+                }
+                let stone = registry.default_state("minecraft:stone").unwrap();
+                for x in -16..32 {
+                    for z in -16..32 {
+                        world.set(x, 0, z, stone).unwrap();
+                    }
+                }
+            },
+            |w, _| {
+                let mut events = Vec::new();
+                ai_step(&mut foal, w, &mut events);
+                out = Some(foal.ai.nav.target_pos);
+            },
+        );
+        out
+    }
+
+    /// `AbstractHorse.followMommy`: a bred foal that is not eating keeps a path
+    /// to the nearest bred `AbstractHorse` within 16 blocks while it is more
+    /// than two blocks away.
+    #[test]
+    fn a_bred_foal_paths_to_the_nearest_bred_horse() {
+        let Some(_) = target_pos((true, true, false), &[]) else {
+            return;
+        };
+        assert_eq!(
+            target_pos((true, true, false), &[("minecraft:horse", 6.5, true)]).unwrap(),
+            Some([6, 1, 0]),
+            "a bred foal walks to the grown horse"
+        );
+        // The nearest of two, whatever the kind.
+        assert_eq!(
+            target_pos(
+                (true, true, false),
+                &[
+                    ("minecraft:horse", 12.5, true),
+                    ("minecraft:donkey", 6.5, true)
+                ]
+            )
+            .unwrap(),
+            Some([6, 1, 0]),
+            "the nearer of the herd"
+        );
+        // `isBred`, `isBaby` and `!isEating` on the foal itself.
+        assert_eq!(
+            target_pos((false, true, false), &[("minecraft:horse", 6.5, true)]).unwrap(),
+            None,
+            "a foal that is not bred does not follow"
+        );
+        assert_eq!(
+            target_pos((true, false, false), &[("minecraft:horse", 6.5, true)]).unwrap(),
+            None,
+            "an adult does not follow"
+        );
+        assert_eq!(
+            target_pos((true, true, true), &[("minecraft:horse", 6.5, true)]).unwrap(),
+            None,
+            "a foal busy eating does not follow"
+        );
+        // `MOMMY_TARGETING`: an AbstractHorse, and bred.
+        assert_eq!(
+            target_pos((true, true, false), &[("minecraft:horse", 6.5, false)]).unwrap(),
+            None,
+            "the grown horse must be bred too"
+        );
+        assert_eq!(
+            target_pos((true, true, false), &[("minecraft:cow", 6.5, true)]).unwrap(),
+            None,
+            "another kind is no mommy"
+        );
+        // 16 blocks of `MOMMY_TARGETING`, and more than two away.
+        assert_eq!(
+            target_pos((true, true, false), &[("minecraft:horse", 20.5, true)]).unwrap(),
+            None,
+            "out of the 16-block range"
+        );
+        assert_eq!(
+            target_pos((true, true, false), &[("minecraft:horse", 1.5, true)]).unwrap(),
+            None,
+            "already at its side"
+        );
+    }
+}

crates/horizon-client/src/mobs/witch.rs

@@ -224,9 +224,9 @@ fn witch_attack(m: &mut Mob, who: Who, _power: f32, cx: &mut Cx) {
     };
     let start = Vec3::new(m.position.x, m.eye_y() - 0.1, m.position.z);
     let mut p = Projectile::new(
-        ProjectileKind::Potion(Box::new(
+        ProjectileKind::potion(
             crate::items::ItemStack::new("minecraft:splash_potion", 1).with_potion(potion),
-        )),
+        ),
         start,
         Some(Who::Mob(m.id)),
     );

crates/horizon-client/src/mod_api.rs

@@ -492,3 +492,101 @@ mod generated;
 pub use generated::Hooks;
 #[doc(hidden)]
 pub use generated::*;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// A double with the three `Host` methods the probe calls.
+    struct Reader {
+        block: &'static str,
+        lines: Vec<Text>,
+    }
+
+    impl Host for Reader {
+        fn block(&self, _pos: [i32; 3]) -> String {
+            self.block.to_string()
+        }
+        fn acting_player(&self) -> Option<NativeServerPlayer> {
+            Some(NativeServerPlayer {
+                uuid: 7,
+                name: "Probe".to_string(),
+                permission: 0,
+                dimension: "minecraft:overworld".to_string(),
+                position: [0.0; 3],
+                game_mode: 0,
+                health: 20.0,
+                yaw: 0.0,
+                pitch: 0.0,
+            })
+        }
+        fn action_bar(&mut self, _uuid: u128, line: Text) -> bool {
+            self.lines.push(line);
+            true
+        }
+    }
+
+    /// Claims a use on stone, after telling the player what the block is.
+    struct Probe;
+
+    impl Hooks for Probe {
+        fn use_item_on(&self, host: &mut dyn Host, event: &mut UseItemOnEvent<'_>) -> Flow {
+            let block = host.block(event.pos);
+            let player = host.acting_player().expect("a player acts");
+            host.action_bar(player.uuid, Text::literal(block.clone()));
+            if block == "minecraft:stone" {
+                Flow::Cancel
+            } else {
+                Flow::Continue
+            }
+        }
+    }
+
+    /// Asks the host to tell a player without anyone having implemented it.
+    struct Chatty;
+
+    impl Hooks for Chatty {
+        fn use_item_on(&self, host: &mut dyn Host, _event: &mut UseItemOnEvent<'_>) -> Flow {
+            host.tell(7, Text::literal("hello"));
+            Flow::Continue
+        }
+    }
+
+    fn stick() -> ItemStack {
+        ItemStack {
+            item: Arc::from("minecraft:stick"),
+            count: 1,
+            damage: 0,
+            extra: None,
+        }
+    }
+
+    #[test]
+    fn a_test_host_implements_only_what_its_hook_calls() {
+        let mods = [Box::new(Probe) as Box<dyn Hooks>];
+        let stack = stick();
+        for (block, expected) in [("minecraft:stone", true), ("minecraft:dirt", false)] {
+            let mut host = Reader {
+                block,
+                lines: Vec::new(),
+            };
+            let mut claimed = false;
+            dispatch_use_item_on(&mut host, &mods, &stack, [1, 2, 3], [0, 1, 0], &mut claimed);
+            assert_eq!(claimed, expected, "{block}");
+            let told: Vec<String> = host.lines.iter().map(Text::plain).collect();
+            assert_eq!(told, [block], "{block}");
+        }
+    }
+
+    #[test]
+    #[should_panic(expected = "Host::tell")]
+    fn an_unexpected_host_call_names_the_method() {
+        let mods = [Box::new(Chatty) as Box<dyn Hooks>];
+        let mut host = Reader {
+            block: "minecraft:stone",
+            lines: Vec::new(),
+        };
+        let mut claimed = false;
+        dispatch_use_item_on(&mut host, &mods, &stick(), [0; 3], [0, 1, 0], &mut claimed);
+    }
+}

crates/horizon-client/src/mod_api/generated.rs

@@ -711,9 +711,15 @@ pub trait Hooks: Send + Sync {
     /// an arrival through a portal). `entity` is its ID and `kind` its type
     /// (`minecraft:item`). It is already in the level's lists, so helpers that
     /// take an entity ID find it. Set `canceled` to keep it out: it is taken
-    /// back out as if never added, and a `/summon` of it fails. 47 tells
-    /// item entities and experience orbs; later APIs add other kinds, so check
-    /// `kind`. Server-side.
+    /// back out as if never added, and a `/summon` of it fails. Tells every
+    /// kind in the game's entity lists (items, orbs, mobs, boats, minecarts,
+    /// armor stands, primed TNT, falling blocks, projectiles, rockets,
+    /// tridents), once each, in the order they were created; check `kind`. A
+    /// gameplay spawn is told when the next tick starts (a drop, an orb, a mob, a
+    /// `/summon` and a chunk's entities are told at once). A mod that
+    /// cancels one of the others sees it removed before it ticks again.
+    /// Not told: end crystals, the dragon, cushions, paintings, item frames and
+    /// the entities Horizon keeps without simulating. Server-side.
     ///
     /// Return `Flow::Cancel` to take it: this sets `canceled`, and later mods are skipped.
     fn entity_join_level(&self, host: &mut dyn Host, event: &mut EntityJoinLevelEvent<'_>) -> Flow {
@@ -3221,6 +3227,23 @@ pub trait Hooks: Send + Sync {
         let _ = event;
         Flow::Continue
     }
+    /// An item frame (`minecraft:item_frame`, `minecraft:glow_item_frame`) or
+    /// a painting (`minecraft:painting`), `kind` its entity type and `pos` the
+    /// block it hangs in, is about to break: a server player's hit
+    /// (`player`, their state swapped in, so `native_tell` answers them), a
+    /// blast, or the wall it hangs on gone (`player` None for both). Where
+    /// `BlockAttachedEntity.hurtServer` and its survival check would kill
+    /// it, before anything drops or sounds. Set `cancel` and it stays, as it
+    /// was. A hit that only takes the item out of a frame does not break the
+    /// frame and is not asked. The game's own player's hit is not asked, nor
+    /// is `/kill`. @API:native_hanging_break@.
+    ///
+    /// Return `Flow::Cancel` to take it: this sets `cancel`, and later mods are skipped.
+    fn hanging_break(&self, host: &mut dyn Host, event: &mut HangingBreakEvent<'_>) -> Flow {
+        let _ = host;
+        let _ = event;
+        Flow::Continue
+    }
     /// A server player places a hanging entity: an item frame
     /// (`minecraft:item_frame`, `minecraft:glow_item_frame`), a painting
     /// (`minecraft:painting`) or a leash knot (`minecraft:leash_knot`, when a
@@ -3284,6 +3307,17 @@ pub trait Hooks: Send + Sync {
         let _ = host;
         let _ = event;
     }
+    /// A player's data was copied to their new player (NeoForge's
+    /// `PlayerEvent.Clone`, from `ServerPlayer.restoreFrom`): `was_death` is
+    /// true after a death, false when they left the End after the credits
+    /// (`respawn` with `keepAllPlayerData`). The uuid stays the same, so the
+    /// old and the new player share `player`. Heard before the new player is
+    /// placed, on a server, with no player's state swapped in. Not
+    /// cancellable.
+    fn player_clone(&self, host: &mut dyn Host, event: &mut PlayerCloneEvent<'_>) {
+        let _ = host;
+        let _ = event;
+    }
     /// The command tree a server sends a player (NeoForge's and Paper's
     /// "commands sent to a player" stage): when they join and when their
     /// level changes (`/op`, `/deop`, the LAN settings). `names` are the
@@ -3414,6 +3448,18 @@ pub trait Hooks: Send + Sync {
         let _ = host;
         let _ = event;
     }
+    /// A player was loaded from the world's save (NeoForge's
+    /// `PlayerEvent.LoadFromFile`, `PlayerList.loadPlayerData`): their `.dat`
+    /// has been read and applied, and they are not placed in a level yet.
+    /// `directory` is the world's player directory (`players/data`): a mod
+    /// reads its own file there, named `<uuid>.<suffix>` as
+    /// `getPlayerFile(suffix)` names it. Heard once for each join, for the
+    /// owner of an integrated server as for anyone else, on a server, with no
+    /// player's state swapped in. Not cancellable.
+    fn player_load_from_file(&self, host: &mut dyn Host, event: &mut PlayerLoadFromFileEvent<'_>) {
+        let _ = host;
+        let _ = event;
+    }
     /// A player whose login the server has accepted (NeoForge's
     /// `PlayerNegotiationEvent` stage): the name, whitelist, ban and
     /// server-full checks have passed and the player holds a place, but their
@@ -3434,6 +3480,18 @@ pub trait Hooks: Send + Sync {
         let _ = event;
         Flow::Continue
     }
+    /// A player was saved to the world's store (NeoForge's
+    /// `PlayerEvent.SaveToFile`, `PlayerList.save`): when they leave or the
+    /// world closes, when the dedicated server saves everyone, and for an
+    /// integrated server's owner when the world saves them. LAN guests are
+    /// not heard on integrated autosaves. Once for each save. `directory`
+    /// is the world's player directory (`players/data`): write your own file
+    /// there, named `<uuid>.<suffix>`, never the player's `.dat`. The player
+    /// may be leaving, so no player's state is swapped in. Not cancellable.
+    fn player_save_to_file(&self, host: &mut dyn Host, event: &mut PlayerSaveToFileEvent<'_>) {
+        let _ = host;
+        let _ = event;
+    }
     /// A server player's sprint started or stopped: their client sent
     /// `START_SPRINTING` or `STOP_SPRINTING` (the sprint key, a double tap
     /// forward, or letting go) and the server's player is now `sprinting`
@@ -3607,6 +3665,21 @@ pub trait Hooks: Send + Sync {
         let _ = host;
         let _ = event;
     }
+    /// A criterion of a server player's advancement was granted or revoked,
+    /// after its progress changed and before any completion rewards, except
+    /// the `minecraft:tick` criteria granted on a network player's first tick
+    /// or a reload, which are heard after that tick's rewards and packets. A
+    /// grant or revoke that changes nothing is not heard. `granted` is false for a
+    /// revoke. Helpers looking up the guest through `self.lan` may find
+    /// nothing during its packet. @API:player_advancement_progress@.
+    fn player_advancement_progress(
+        &self,
+        host: &mut dyn Host,
+        event: &mut PlayerAdvancementProgressEvent<'_>,
+    ) {
+        let _ = host;
+        let _ = event;
+    }
     /// A server player reset their attack strength by swinging (`handlePunch`).
     /// The swing and reset have already happened. The player's state is not
     /// swapped in, and helpers looking them up through `self.lan` may find
@@ -3898,6 +3971,19 @@ pub trait Hooks: Send + Sync {
         let _ = event;
         Flow::Continue
     }
+    /// A statistic is about to be awarded to a server player, before its count
+    /// and scoreboard criteria change. `stat_type` and `stat` are ids such as
+    /// `minecraft:mined` and `minecraft:stone`, and `value` the amount. Set
+    /// `cancel` to award nothing. Helpers looking up the guest through
+    /// `self.lan` may find nothing during its packet. Server-side.
+    /// @API:player_stat_award@.
+    ///
+    /// Return `Flow::Cancel` to take it: this sets `cancel`, and later mods are skipped.
+    fn player_stat_award(&self, host: &mut dyn Host, event: &mut PlayerStatAwardEvent<'_>) -> Flow {
+        let _ = host;
+        let _ = event;
+        Flow::Continue
+    }
     /// A server player selected a stonecutter recipe, after the menu accepted
     /// its button. `recipe` is the zero-based button index. Guest lookup
     /// helpers may find nothing during packet handling. Server-side.
@@ -10443,6 +10529,32 @@ pub fn dispatch_food_level_changed(
     }
     *to = event.to;
 }
+/// What [`Hooks::hanging_break`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
+#[non_exhaustive]
+pub struct HangingBreakEvent<'a> {
+    pub player: Option<u128>,
+    pub kind: &'a str,
+    pub pos: [i32; 3],
+}
+pub fn dispatch_hanging_break(
+    host: &mut dyn Host,
+    mods: &[Box<dyn Hooks>],
+    player: Option<u128>,
+    kind: &str,
+    pos: [i32; 3],
+    cancel: &mut bool,
+) {
+    if *cancel {
+        return;
+    }
+    let mut event = HangingBreakEvent { player, kind, pos };
+    for mod_hook in mods {
+        if matches!(mod_hook.hanging_break(host, &mut event), Flow::Cancel) {
+            *cancel = true;
+            break;
+        }
+    }
+}
 /// What [`Hooks::hanging_place`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
 #[non_exhaustive]
 pub struct HangingPlaceEvent<'a> {
@@ -10536,6 +10648,29 @@ pub fn dispatch_player_changed_dimension(
         mod_hook.player_changed_dimension(host, &mut event);
     }
 }
+/// What [`Hooks::player_clone`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
+#[non_exhaustive]
+pub struct PlayerCloneEvent<'a> {
+    pub player: u128,
+    pub name: &'a str,
+    pub was_death: bool,
+}
+pub fn dispatch_player_clone(
+    host: &mut dyn Host,
+    mods: &[Box<dyn Hooks>],
+    player: u128,
+    name: &str,
+    was_death: bool,
+) {
+    let mut event = PlayerCloneEvent {
+        player,
+        name,
+        was_death,
+    };
+    for mod_hook in mods {
+        mod_hook.player_clone(host, &mut event);
+    }
+}
 /// What [`Hooks::player_commands_sent`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
 #[non_exhaustive]
 pub struct PlayerCommandsSentEvent<'a> {
@@ -10790,6 +10925,29 @@ pub fn dispatch_player_lectern_page_change(
         mod_hook.player_lectern_page_change(host, &mut event);
     }
 }
+/// What [`Hooks::player_load_from_file`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
+#[non_exhaustive]
+pub struct PlayerLoadFromFileEvent<'a> {
+    pub player: u128,
+    pub name: &'a str,
+    pub directory: &'a std::path::Path,
+}
+pub fn dispatch_player_load_from_file(
+    host: &mut dyn Host,
+    mods: &[Box<dyn Hooks>],
+    player: u128,
+    name: &str,
+    directory: &std::path::Path,
+) {
+    let mut event = PlayerLoadFromFileEvent {
+        player,
+        name,
+        directory,
+    };
+    for mod_hook in mods {
+        mod_hook.player_load_from_file(host, &mut event);
+    }
+}
 /// What [`Hooks::player_login`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
 #[non_exhaustive]
 pub struct PlayerLoginEvent<'a> {
@@ -10820,6 +10978,29 @@ pub fn dispatch_player_login(
         }
     }
 }
+/// What [`Hooks::player_save_to_file`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
+#[non_exhaustive]
+pub struct PlayerSaveToFileEvent<'a> {
+    pub player: u128,
+    pub name: &'a str,
+    pub directory: &'a std::path::Path,
+}
+pub fn dispatch_player_save_to_file(
+    host: &mut dyn Host,
+    mods: &[Box<dyn Hooks>],
+    player: u128,
+    name: &str,
+    directory: &std::path::Path,
+) {
+    let mut event = PlayerSaveToFileEvent {
+        player,
+        name,
+        directory,
+    };
+    for mod_hook in mods {
+        mod_hook.player_save_to_file(host, &mut event);
+    }
+}
 /// What [`Hooks::player_sprint`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
 #[non_exhaustive]
 pub struct PlayerSprintEvent<'a> {
@@ -11132,6 +11313,35 @@ pub fn dispatch_player_advancement_done(
         mod_hook.player_advancement_done(host, &mut event);
     }
 }
+/// What [`Hooks::player_advancement_progress`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
+#[non_exhaustive]
+pub struct PlayerAdvancementProgressEvent<'a> {
+    pub player: u128,
+    pub name: &'a str,
+    pub advancement: &'a str,
+    pub criterion: &'a str,
+    pub granted: bool,
+}
+pub fn dispatch_player_advancement_progress(
+    host: &mut dyn Host,
+    mods: &[Box<dyn Hooks>],
+    player: u128,
+    name: &str,
+    advancement: &str,
+    criterion: &str,
+    granted: bool,
+) {
+    let mut event = PlayerAdvancementProgressEvent {
+        player,
+        name,
+        advancement,
+        criterion,
+        granted,
+    };
+    for mod_hook in mods {
+        mod_hook.player_advancement_progress(host, &mut event);
+    }
+}
 /// What [`Hooks::player_attack_cooldown_reset`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
 #[non_exhaustive]
 pub struct PlayerAttackCooldownResetEvent<'a> {
@@ -11858,6 +12068,42 @@ pub fn dispatch_player_spawn_point_set(
         }
     }
 }
+/// What [`Hooks::player_stat_award`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
+#[non_exhaustive]
+pub struct PlayerStatAwardEvent<'a> {
+    pub player: u128,
+    pub name: &'a str,
+    pub stat_type: &'a str,
+    pub stat: &'a str,
+    pub value: i32,
+}
+pub fn dispatch_player_stat_award(
+    host: &mut dyn Host,
+    mods: &[Box<dyn Hooks>],
+    player: u128,
+    name: &str,
+    stat_type: &str,
+    stat: &str,
+    value: i32,
+    cancel: &mut bool,
+) {
+    if *cancel {
+        return;
+    }
+    let mut event = PlayerStatAwardEvent {
+        player,
+        name,
+        stat_type,
+        stat,
+        value,
+    };
+    for mod_hook in mods {
+        if matches!(mod_hook.player_stat_award(host, &mut event), Flow::Cancel) {
+            *cancel = true;
+            break;
+        }
+    }
+}
 /// What [`Hooks::player_stonecutter_recipe_select`] is told. Fields may be added: the struct is `#[non_exhaustive]`.
 #[non_exhaustive]
 pub struct PlayerStonecutterRecipeSelectEvent<'a> {

crates/horizon-client/src/projectiles.rs

@@ -111,11 +111,21 @@ pub enum ProjectileKind {
     /// flies as (`ThrowableItemProjectile.getItem`). What it splashes is that
     /// stack's `potion_contents`, so a witch's potion and a summoned one are
     /// the same thing; its entity type is the stack's item.
-    Potion(Box<crate::items::ItemStack>),
+    ///
+    /// The `bool` is whether its entity type is `ThrownLingeringPotion`: the
+    /// type is the entity's own and `/summon` can pair either with any `Item`,
+    /// so it is kept next to the stack (a thrown potion's follows its item).
+    Potion(Box<crate::items::ItemStack>, bool),
     /// a content mod's type.
     Thrown(&'static ThrownType),
 }
 impl ProjectileKind {
+    /// A thrown potion flying as `stack`: a lingering item makes the lingering
+    /// entity type, any other the splash one.
+    pub fn potion(stack: crate::items::ItemStack) -> Self {
+        let lingering = &*stack.item == "minecraft:lingering_potion";
+        Self::Potion(Box::new(stack), lingering)
+    }
     /// Wind charges take no push from an explosion (vanilla leaves their motion at 0).
     pub fn ignores_blast(&self) -> bool {
         matches!(self, Self::WindCharge | Self::BreezeWindCharge)
@@ -137,7 +147,7 @@ impl ProjectileKind {
             | Self::Egg
             | Self::EnderPearl
             | Self::LlamaSpit
-            | Self::Potion(_)
+            | Self::Potion(..)
             | Self::Thrown(_) => 0.25,
             Self::SmallFireball
             | Self::WindCharge
@@ -163,20 +173,12 @@ impl ProjectileKind {
             Self::ShulkerBullet { .. } => "minecraft:shulker_bullet",
             Self::WitherSkull { .. } => "minecraft:wither_skull",
             // `ThrownSplashPotion`/`ThrownLingeringPotion`: the item names it.
-            Self::Potion(stack) => potion_entity_type(&stack.item),
+            Self::Potion(_, true) => "minecraft:lingering_potion",
+            Self::Potion(_, false) => "minecraft:splash_potion",
             Self::Thrown(t) => t.id,
         }
     }
 }
-/// The entity type a thrown potion's item names: `ThrownSplashPotion` for a
-/// splash potion, `ThrownLingeringPotion` for a lingering one.
-fn potion_entity_type(item: &str) -> &'static str {
-    if item == "minecraft:lingering_potion" {
-        "minecraft:lingering_potion"
-    } else {
-        "minecraft:splash_potion"
-    }
-}
 /// `ThrownItemRenderer`'s sprite for a thrown potion.
 fn potion_sprite(item: &str) -> &'static str {
     if item == "minecraft:lingering_potion" {
@@ -1001,7 +1003,7 @@ impl Projectile {
     /// (`ThrownItemRenderer`): the potion stack itself, or the type's item.
     pub fn drawn_item(&self) -> Option<crate::items::ItemStack> {
         match &self.kind {
-            ProjectileKind::Potion(stack) => Some((**stack).clone()),
+            ProjectileKind::Potion(stack, _) => Some((**stack).clone()),
             ProjectileKind::Thrown(t) => Some(crate::items::ItemStack::new(t.item, 1)),
             _ => None,
         }
@@ -1015,7 +1017,7 @@ impl Projectile {
             ProjectileKind::SmallFireball | ProjectileKind::LargeFireball { .. } => {
                 "item/fire_charge"
             }
-            ProjectileKind::Potion(stack) => potion_sprite(&stack.item),
+            ProjectileKind::Potion(stack, _) => potion_sprite(&stack.item),
             ProjectileKind::LlamaSpit => "entity/llama/llama_spit",
             // Drawn as `WindChargeModel` and `ShulkerBulletModel` by the game.
             ProjectileKind::WindCharge

crates/horizon-server/src/events.rs

@@ -87,9 +87,13 @@ pub fn poll_game(shared: Arc<Shared>) {
                 continue;
             };
             // A new game numbers its events from 1 again.
+            let mut history = false;
             if control.as_ref().is_none_or(|(p, _)| *p != pid) {
                 control = engine::Control::connect(&shared.dir).ok().map(|c| (pid, c));
                 since = 0;
+                // What the game recorded before this first fetch (its saves while it started) happened before
+                // the management protocol's clients could hear of it.
+                history = true;
             }
             let Some((_, game)) = control.as_mut() else {
                 continue;
@@ -105,6 +109,9 @@ pub fn poll_game(shared: Arc<Shared>) {
                 if let Some(fields) = event.as_object_mut() {
                     fields.remove("seq");
                 }
+                if !(history && matches!(kind.as_str(), "saving" | "saved")) {
+                    crate::management::game_event(&shared, &kind, &event);
+                }
                 shared.emit(&kind, event);
             }
         }

crates/horizon-server/src/management.rs

@@ -72,6 +72,21 @@ pub fn started(shared: &Shared) {
     notify(shared, "notification/server/started", None);
 }
 
+/// The notification a typed event of the game is, if vanilla sends one for it: a player who joined or left
+/// (`playerJoined`, `playerLeft`, with the player as a `PlayerDto`), and a world save that began or ended
+/// (`serverSaveStarted`, `serverSaveCompleted`).
+pub fn game_event(shared: &Shared, kind: &str, event: &Value) {
+    let player = || Some(json!({ "id": event["uuid"], "name": event["name"] }));
+    let (method, params) = match kind {
+        "join" => ("notification/players/joined", player()),
+        "leave" => ("notification/players/left", player()),
+        "saving" => ("notification/server/saving", None),
+        "saved" => ("notification/server/saved", None),
+        _ => return,
+    };
+    notify(shared, method, params);
+}
+
 /// `NotificationService.serverShuttingDown`, which `DedicatedServer.stopServer` sends first of all.
 pub fn stopping(shared: &Shared) {
     if !shared.management.stopping_told.swap(true, Ordering::SeqCst) {
@@ -765,12 +780,20 @@ mod tests {
         stream
     }
 
-    /// The text of the next frame the server sends (unmasked, short enough for a 7-bit length).
+    /// The text of the next frame the server sends (unmasked, shorter than 65536 bytes).
     fn next_text(stream: &mut TcpStream) -> String {
         let mut head = [0u8; 2];
         stream.read_exact(&mut head).unwrap();
         assert_eq!(head[0], 0x81);
-        let mut payload = vec![0u8; usize::from(head[1])];
+        let length = match head[1] {
+            126 => {
+                let mut b = [0u8; 2];
+                stream.read_exact(&mut b).unwrap();
+                usize::from(u16::from_be_bytes(b))
+            }
+            n => usize::from(n),
+        };
+        let mut payload = vec![0u8; length];
         stream.read_exact(&mut payload).unwrap();
         String::from_utf8(payload).unwrap()
     }
@@ -829,6 +852,47 @@ mod tests {
         assert_eq!(shared.management.sockets.lock().unwrap().len(), 1);
     }
 
+    #[test]
+    fn the_games_events_become_the_notifications_vanilla_sends() {
+        let shared = shared();
+        let address = listen_on(shared.clone(), settings());
+        let mut client = upgrade(address);
+        registered(&shared, 1);
+        let id = "0123abcd-0000-4000-8000-00000000000a";
+        let joined = json!({ "type": "join", "name": "Kim0", "uuid": id });
+        game_event(&shared, "join", &joined);
+        game_event(
+            &shared,
+            "chat",
+            &json!({ "name": "Kim0", "uuid": id, "message": "hi" }),
+        );
+        game_event(&shared, "saving", &json!({ "type": "saving" }));
+        game_event(&shared, "saved", &json!({ "type": "saved" }));
+        game_event(&shared, "leave", &json!({ "name": "Kim0", "uuid": id }));
+        // The chat is not a notification; the rest come in order, the player as a `PlayerDto`.
+        let player = format!(r#"[{{"id":"{id}","name":"Kim0"}}]"#);
+        assert_eq!(
+            next_text(&mut client),
+            format!(
+                r#"{{"jsonrpc":"2.0","method":"minecraft:notification/players/joined","params":{player}}}"#
+            )
+        );
+        assert_eq!(
+            next_text(&mut client),
+            r#"{"jsonrpc":"2.0","method":"minecraft:notification/server/saving"}"#
+        );
+        assert_eq!(
+            next_text(&mut client),
+            r#"{"jsonrpc":"2.0","method":"minecraft:notification/server/saved"}"#
+        );
+        assert_eq!(
+            next_text(&mut client),
+            format!(
+                r#"{{"jsonrpc":"2.0","method":"minecraft:notification/players/left","params":{player}}}"#
+            )
+        );
+    }
+
     #[test]
     fn every_notification_sent_is_one_discover_lists() {
         let listed = schema::discover();
@@ -841,6 +905,10 @@ mod tests {
         for sent in [
             "notification/server/started",
             "notification/server/stopping",
+            "notification/server/saving",
+            "notification/server/saved",
+            "notification/players/joined",
+            "notification/players/left",
         ] {
             assert!(
                 names.contains(&format!("minecraft:{sent}").as_str()),

crates/horizon-server/src/management_methods.rs

@@ -32,6 +32,15 @@ pub fn call(shared: &Shared, client: u32, short: &str, argument: &Value) -> Resu
             Ok(json!(true))
         }
         "server/system_message" => game.system_message(argument),
+        "serversettings/autosave" => game.autosave(client, None),
+        "serversettings/autosave/set" => game.autosave(
+            client,
+            Some(
+                argument
+                    .as_bool()
+                    .ok_or_else(|| invalid_params(format!("Not a boolean: {argument}")))?,
+            ),
+        ),
         "serversettings/motd" => game.motd(client, None),
         "serversettings/motd/set" => game.motd(
             client,
@@ -299,6 +308,21 @@ struct Game<'a> {
 }
 
 impl Game<'_> {
+    /// `MinecraftServerSettingsServiceImpl.isAutoSave`: read the game's live save flag.
+    /// `MinecraftServerSettingsServiceImpl.setAutoSave`: update that flag and return its new value.
+    fn autosave(&self, client: u32, value: Option<bool>) -> Result<Value, Failure> {
+        let mut request = json!({ "method": "serversettings/autosave" });
+        if let Some(value) = value {
+            request["method"] = json!("serversettings/autosave/set");
+            request["value"] = json!(value);
+        }
+        let reply = self.ask(&format!("management {client} {request}"))?;
+        if let Some(error) = reply["error"].as_str() {
+            return Err((INTERNAL_ERROR, Some(error.to_owned())));
+        }
+        Ok(reply["value"].clone())
+    }
+
     /// `MinecraftServerSettingsServiceImpl.forceGameMode` and `setForceGameMode`.
     fn force_game_mode(&self, client: u32, value: Option<bool>) -> Result<Value, Failure> {
         let mut request = json!({ "method": "serversettings/force_game_mode" });

crates/horizon-shaders/src/translate/geometry.rs

@@ -12,7 +12,7 @@
 use std::collections::BTreeSet;
 use std::fmt::Write;
 
-use super::scan::significant;
+use super::scan::{QUALIFIERS, STORAGE, significant};
 use super::{Error, GbuffersInputs, Program, Target};
 use crate::Preprocessed;
 use crate::macros::lex;
@@ -158,22 +158,9 @@ fn classify(tokens: &[&str], range: std::ops::Range<usize>) -> Statement {
             }
             k += 1;
         }
-        let quals = [
-            "in",
-            "out",
-            "attribute",
-            "varying",
-            "flat",
-            "smooth",
-            "noperspective",
-            "centroid",
-            "invariant",
-            "highp",
-            "mediump",
-            "lowp",
-            "const",
-        ];
-        while k < words.len() && quals.contains(&words[k]) {
+        // Every qualifier the translator knows (`sample`, `precise`...), in any order (GLSL
+        // 4.60, 4.12): one it missed would be taken for the type, and the type for a name.
+        while k < words.len() && (STORAGE.contains(&words[k]) || QUALIFIERS.contains(&words[k])) {
             k += 1;
         }
         match words.get(k) {
@@ -246,8 +233,14 @@ fn combine(
             message,
         }]
     };
-    let gs_tokens = lex(&geometry.code);
-    let vs_tokens = lex(&vertex.code);
+    // Interface blocks first become plain varyings (`interface_blocks`), the vertex stage's
+    // `out` block and the geometry stage's `in` array alike: what follows reads declarations
+    // of one type each. The geometry stage's input blocks read as `hz_in_<block>_<member>`,
+    // apart from its output blocks, which may have the same names.
+    let gs_code = super::interface_blocks::flatten_as(&geometry.code, "in_");
+    let vs_code = super::interface_blocks::flatten(&vertex.code);
+    let gs_tokens = lex(gs_code.as_deref().unwrap_or(&geometry.code));
+    let vs_tokens = lex(vs_code.as_deref().unwrap_or(&vertex.code));
     let gs = statements(&gs_tokens);
     let vs = statements(&vs_tokens);
 
@@ -429,8 +422,12 @@ fn combine(
     }
     main.push_str("        hz_vs_main();\n");
     for (name, _) in &vs_outs {
-        if gs_ins.iter().any(|(n, _)| n == name) {
-            writeln!(main, "        {name}[hz_i] = hz_vs_{name};").unwrap();
+        let block = name.strip_prefix("hz_").map(|m| format!("hz_in_{m}"));
+        if let Some((input, _)) = gs_ins
+            .iter()
+            .find(|(n, _)| n == name || Some(n) == block.as_ref())
+        {
+            writeln!(main, "        {input}[hz_i] = hz_vs_{name};").unwrap();
         }
     }
     main.push_str("        hz_gl_in[hz_i].p = hz_vs_Position;\n    }\n    hz_gs_main();\n");
@@ -583,17 +580,8 @@ mod tests {
     use crate::pack::tests::zip;
     use crate::{Macros, Pack, preprocess};
 
-    #[test]
-    fn a_geometry_stage_folds_into_the_vertex_stage() {
-        let vsh = "#version 430\nout vec3 vPos;\nout vec4 vColor;\nvoid main() {\n    \
-                   vPos = gl_Vertex.xyz;\n    vColor = gl_Color * float(gl_InstanceID + 1);\n    \
-                   gl_Position = ftransform();\n}\n";
-        let gsh = "#version 430\nlayout(triangles) in;\nlayout(triangle_strip, max_vertices = 4) out;\n\
-                   in vec3 vPos[];\nin vec4 vColor[];\nout vec4 gColor;\nvoid main() {\n    \
-                   for (int i = 0; i < 3; i++) {\n        gColor = vColor[i];\n        \
-                   gl_Position = gl_in[i].gl_Position;\n        EmitVertex();\n    }\n    \
-                   gl_Position = vec4(vPos[0], 1.0);\n    EmitVertex();\n    EndPrimitive();\n}\n";
-        let fsh = "#version 430\nin vec4 gColor;\nvoid main() {\n    gl_FragData[0] = gColor;\n}\n";
+    /// `vsh`, `gsh` and `fsh` (a pack's shadow program) folded and translated.
+    fn fold(vsh: &str, gsh: &str, fsh: &str) -> Result<(Program, u32), Vec<Error>> {
         let pack = Pack::from_zip_bytes(
             "P.zip",
             zip(&[
@@ -617,19 +605,73 @@ mod tests {
                 .into(),
             index: "uint(@)".into(),
         };
-        let (program, triangles) = translate_geometry(
+        translate_geometry(
             &pp("shadow.vsh"),
             &pp("shadow.gsh"),
             &pp("shadow.fsh"),
             &inputs,
         )
-        .unwrap_or_else(|e| panic!("{e:?}"));
+    }
+
+    #[test]
+    fn a_geometry_stage_folds_into_the_vertex_stage() {
+        let vsh = "#version 430\nout vec3 vPos;\nout vec4 vColor;\nvoid main() {\n    \
+                   vPos = gl_Vertex.xyz;\n    vColor = gl_Color * float(gl_InstanceID + 1);\n    \
+                   gl_Position = ftransform();\n}\n";
+        let gsh = "#version 430\nlayout(triangles) in;\nlayout(triangle_strip, max_vertices = 4) out;\n\
+                   in vec3 vPos[];\nin vec4 vColor[];\nout vec4 gColor;\nvoid main() {\n    \
+                   for (int i = 0; i < 3; i++) {\n        gColor = vColor[i];\n        \
+                   gl_Position = gl_in[i].gl_Position;\n        EmitVertex();\n    }\n    \
+                   gl_Position = vec4(vPos[0], 1.0);\n    EmitVertex();\n    EndPrimitive();\n}\n";
+        let fsh = "#version 430\nin vec4 gColor;\nvoid main() {\n    gl_FragData[0] = gColor;\n}\n";
+        let (program, triangles) = fold(vsh, gsh, fsh).unwrap_or_else(|e| panic!("{e:?}"));
         // A strip of four corners is two triangles.
         assert_eq!(triangles, 2);
         assert_eq!(program.vertex.entry_points.len(), 1);
         assert_eq!(program.fragment.entry_points.len(), 1);
     }
 
+    /// Stages that pass their varyings in interface blocks (GLSL 4.60, 4.3.9), members with
+    /// their own qualifiers: the vertex stage's `out` block, the geometry stage's `in` block
+    /// array and `out` block, the fragment stage's `in` block. The geometry stage's two blocks
+    /// share a name, as an input and an output block may (4.3.9).
+    #[test]
+    fn interface_blocks_pass_between_the_stages() {
+        let vsh = "#version 430\nuniform float far;\n\
+                   out VertexData {\n    vec4 color;\n    flat float id;\n    vec2 uv;\n} vOut;\n\
+                   void main() {\n    vOut.color = gl_Color;\n    vOut.id = far;\n    \
+                   vOut.uv = gl_Vertex.xy;\n    gl_Position = ftransform();\n}\n";
+        let gsh = "#version 430\nlayout(triangles) in;\nlayout(triangle_strip, max_vertices = 3) out;\n\
+                   in VertexData {\n    vec4 color;\n    flat float id;\n    vec2 uv;\n} vIn[];\n\
+                   out VertexData {\n    vec4 color;\n    flat float id;\n} gOut;\n\
+                   void main() {\n    for (int i = 0; i < 3; i++) {\n        \
+                   gOut.color = vIn[i].color * vIn[i].uv.x;\n        gOut.id = vIn[0].id;\n        \
+                   gl_Position = gl_in[i].gl_Position;\n        EmitVertex();\n    }\n    \
+                   EndPrimitive();\n}\n";
+        let fsh = "#version 430\nuniform float far;\n\
+                   in VertexData {\n    vec4 color;\n    flat float id;\n} gIn;\n\
+                   void main() {\n    gl_FragData[0] = gIn.color * gIn.id / far;\n}\n";
+        let (program, triangles) = fold(vsh, gsh, fsh).unwrap_or_else(|e| panic!("{e:?}"));
+        assert_eq!(triangles, 1);
+        assert_eq!(program.fragment.entry_points.len(), 1);
+    }
+
+    /// An output qualified `sample` declares no variable named after its type (GLSL 4.60, 4.3).
+    #[test]
+    fn sample_outputs_rename_no_type() {
+        let vsh = "#version 430\nuniform float far;\n\
+                   out sample float vDepth;\nvoid main() {\n    vDepth = far;\n    \
+                   gl_Position = ftransform();\n}\n";
+        let gsh = "#version 430\nlayout(triangles) in;\nlayout(triangle_strip, max_vertices = 3) out;\n\
+                   in float vDepth[];\nout float gDepth;\nvoid main() {\n    \
+                   for (int i = 0; i < 3; i++) {\n        gDepth = vDepth[i];\n        \
+                   gl_Position = gl_in[i].gl_Position;\n        EmitVertex();\n    }\n    \
+                   EndPrimitive();\n}\n";
+        let fsh = "#version 430\nuniform float far;\nin float gDepth;\n\
+                   void main() {\n    gl_FragData[0] = vec4(gDepth / far);\n}\n";
+        fold(vsh, gsh, fsh).unwrap_or_else(|e| panic!("{e:?}"));
+    }
+
     #[test]
     fn writes_run_once_and_keep_their_else() {
         let code =

crates/horizon-shaders/src/translate/interface_blocks.rs

@@ -4,8 +4,10 @@
 //! type, found Interpolation(Flat)"). Each member of such a block becomes a varying of its own,
 //! `hz_<block>_<member>` (the name the next stage's block gives it too: stages match blocks by
 //! block name and members by name), and `instance.member` reads it. A block without an instance
-//! name keeps its members' names. Blocks with an instance array (a geometry stage's input) and
-//! blocks whose instance is used whole are left as written. Lines stay where they were.
+//! name keeps its members' names. Of a block with an instance array (a geometry stage's input,
+//! `in VertexData { vec2 uv; } vIn[];`), each member becomes an array, `vIn[i].uv` reading
+//! `hz_VertexData_uv[i]`. Blocks whose instance is used whole are left as written. Lines stay
+//! where they were.
 
 use super::scan::significant;
 use crate::macros::lex;
@@ -36,10 +38,19 @@ struct Block {
     name: String,
     members: Vec<(usize, Vec<(usize, String)>)>,
     instance: Option<(usize, String)>,
+    /// The instance's array suffix (`[]`, `[3]`), empty when it is not an array.
+    array: String,
 }
 
 /// `code` with its plain `in`/`out` interface blocks as varyings, or `None` when it has none.
 pub(super) fn flatten(code: &str) -> Option<String> {
+    flatten_as(code, "")
+}
+
+/// `flatten`, the members of an `in` block with an instance named `hz_<inputs><block>_<member>`:
+/// a geometry stage's input and output blocks may share their name (GLSL 4.60, 4.3.9), and the
+/// geometry stage reads its inputs under names of its own.
+pub(super) fn flatten_as(code: &str, inputs: &str) -> Option<String> {
     let mut tokens: Vec<String> = lex(code).into_iter().map(str::to_owned).collect();
     let blocks = find_blocks(&tokens);
     if blocks.is_empty() {
@@ -48,17 +59,25 @@ pub(super) fn flatten(code: &str) -> Option<String> {
     let mut changed = false;
     for b in blocks {
         let inside = |i: usize| (b.start..=b.end).contains(&i);
+        let prefix = if b.storage == "in" { inputs } else { "" };
         let renamed = |member: &str| match &b.instance {
-            Some(_) => format!("hz_{}_{member}", b.name),
+            Some(_) => format!("hz_{prefix}{}_{member}", b.name),
             None => member.to_owned(),
         };
-        // Every use of the instance outside the block must be `instance.member`.
+        // Every use of the instance outside the block must be `instance.member`, or
+        // `instance[i].member` for an instance array.
         let mut reads = Vec::new();
         if let Some((_, instance)) = &b.instance {
             let mut whole = false;
             for i in (0..tokens.len()).filter(|&i| !inside(i) && tokens[i] == *instance) {
-                let next = next_significant(&tokens, i + 1);
-                let member = next
+                let index = match b.array.is_empty() {
+                    true => Some(i),
+                    false => next_significant(&tokens, i + 1)
+                        .filter(|&o| tokens[o] == "[")
+                        .and_then(|o| closing(&tokens, o)),
+                };
+                let member = index
+                    .and_then(|x| next_significant(&tokens, x + 1))
                     .filter(|&d| tokens[d] == ".")
                     .and_then(|d| next_significant(&tokens, d + 1));
                 let known = member.filter(|&m| {
@@ -66,8 +85,8 @@ pub(super) fn flatten(code: &str) -> Option<String> {
                         .iter()
                         .any(|(_, names)| names.iter().any(|(_, n)| *n == tokens[m]))
                 });
-                match (next, known) {
-                    (Some(_), Some(m)) => reads.push((i, m)),
+                match (index, known) {
+                    (Some(x), Some(m)) => reads.push((i, x, m)),
                     _ => whole = true,
                 }
             }
@@ -75,10 +94,11 @@ pub(super) fn flatten(code: &str) -> Option<String> {
                 continue;
             }
         }
-        for (i, member) in reads {
+        for (i, index, member) in reads {
             tokens[i] = renamed(&tokens[member]);
-            // `.member` goes, with the spaces around it but not its line breaks.
-            for t in &mut tokens[i + 1..=member] {
+            // `.member` goes, with the spaces around it but not its line breaks; an index stays
+            // (`v[i].m` is `hz_B_m[i]`).
+            for t in &mut tokens[index + 1..=member] {
                 t.retain(|c| c == '\n');
             }
         }
@@ -91,7 +111,8 @@ pub(super) fn flatten(code: &str) -> Option<String> {
         for (first, names) in &b.members {
             tokens[*first] = format!("{} {}", b.storage, tokens[*first]);
             for (at, name) in names {
-                tokens[*at] = renamed(name);
+                // Of an instance array, each member is an array of the instance's size, outermost.
+                tokens[*at] = renamed(name) + &b.array;
             }
         }
         changed = true;
@@ -111,6 +132,24 @@ fn next_significant(tokens: &[String], from: usize) -> Option<usize> {
     (from..tokens.len()).find(|&i| significant(&tokens[i]))
 }
 
+/// The `]` that closes the `[` at `open`.
+fn closing(tokens: &[String], open: usize) -> Option<usize> {
+    let mut depth = 0usize;
+    for (j, t) in tokens.iter().enumerate().skip(open) {
+        match t.as_str() {
+            "[" => depth += 1,
+            "]" => {
+                depth -= 1;
+                if depth == 0 {
+                    return Some(j);
+                }
+            }
+            _ => {}
+        }
+    }
+    None
+}
+
 /// The `in`/`out` interface blocks at global scope that can be flattened.
 fn find_blocks(tokens: &[String]) -> Vec<Block> {
     let mut out = Vec::new();
@@ -235,10 +274,17 @@ fn block(tokens: &[String], start: usize, open: usize) -> Option<Block> {
         .filter(|&j| significant(&tokens[j]))
         .collect();
     let end = (close + 1..tokens.len()).find(|&j| tokens[j] == ";")?;
-    let instance = match after.as_slice() {
-        [] => None,
-        [n] if super::scan::is_ident(&tokens[*n]) => Some((*n, tokens[*n].clone())),
-        _ => return None, // an instance array, or something else
+    let (instance, array) = match after.as_slice() {
+        [] => (None, String::new()),
+        // `vIn[]`, `vIn[3]`: a geometry stage's input (GLSL 4.60, 4.3.9).
+        [n, rest @ ..]
+            if super::scan::is_ident(&tokens[*n])
+                && (rest.is_empty() || tokens[rest[0]] == "[" && tokens[*rest.last()?] == "]") =>
+        {
+            let array = rest.iter().map(|&j| tokens[j].as_str()).collect();
+            (Some((*n, tokens[*n].clone())), array)
+        }
+        _ => return None,
     };
     if members.is_empty() {
         return None;
@@ -252,6 +298,7 @@ fn block(tokens: &[String], start: usize, open: usize) -> Option<Block> {
         name,
         members,
         instance,
+        array,
     })
 }
 
@@ -286,14 +333,26 @@ mod tests {
         );
     }
 
+    #[test]
+    fn an_instance_array_makes_each_member_an_array() {
+        let code = "in VertexData {\n    flat int id;\n    vec2 st[2];\n} vIn[];\n\
+                    void main() { int i = vIn[0].id; vec2 a = vIn[i + 1] . st[1]; }\n";
+        let out = flatten(code).unwrap();
+        assert_eq!(out.lines().count(), code.lines().count());
+        assert_eq!(
+            out.split_whitespace().collect::<Vec<_>>().join(" "),
+            "in flat int hz_VertexData_id[]; in vec2 hz_VertexData_st[][2]; void main() { \
+             int i = hz_VertexData_id[0]; vec2 a = hz_VertexData_st[i + 1][1]; }"
+        );
+    }
+
     #[test]
     fn other_blocks_stay_as_written() {
         for code in [
-            // Uniform and storage blocks, a geometry stage's instance array, an instance
-            // used whole.
+            // Uniform and storage blocks, an instance used whole.
             "uniform Frame { float t; } frame;\nvoid main() {}\n",
             "buffer Data { float v[]; } data;\nvoid main() {}\n",
-            "in VertexData { flat int id; } vIn[];\nvoid main() {}\n",
+            "in VertexData { flat int id; } vIn[];\nvoid f(VertexData d) {}\nvoid main() { f(vIn[0]); }\n",
             "out VertexData { flat int id; } vOut;\nvoid f(int x) {}\nvoid main() { vOut = vOut; }\n",
         ] {
             assert_eq!(flatten(code), None, "{code}");

docs/api/server.md

@@ -80,7 +80,8 @@ addition; a change to one starts `/api/v2`, served beside `/api/v1`.
 - **Mods on a dedicated server**: list, turn on and off, and their settings, once native mods can be built for the
   server ([mods.md](../mods.md), [native-mods.md](../native-mods.md#multiplayer)).
 - **Vanilla's management protocol**: `serversettings/*`, `gamerules`, the notifications other than
-  `server/started` and `server/stopping`, and the status heartbeat. The methods answer an internal error saying
+  `server/started`, `server/stopping`, `server/saving`, `server/saved`, `players/joined` and `players/left`,
+  and the status heartbeat. The methods answer an internal error saying
   so; a kick's translatable message is sent as its key.
 - **Compatibility tests**: golden replies per endpoint, and a `server.toml` from each release line.
 

docs/native-mods.md

@@ -537,8 +537,10 @@ API 47 adds `native_entity_join_level(dimension, entity, kind, pos, loaded_from_
 server level (NeoForge's `EntityJoinLevelEvent`, vanilla's `PersistentEntitySectionManager.addEntity`):
 `loaded_from_disk` is true when it comes back with its chunk, false for a fresh add (a drop, an orb, `/summon`, an
 arrival through a portal into another level). The entity is already in the level's lists when the hook runs; `canceled` takes it back
-out, and a `/summon` of it fails with vanilla's "duplicate UUIDs" message. It tells item entities and experience
-orbs so far; later APIs add other kinds, so check `kind`. Bundles that use it need `"hooks": 47`.
+out, and a `/summon` of it fails with vanilla's "duplicate UUIDs" message. It tells every kind in the game's entity
+lists (items, orbs, mobs, boats, minecarts, armor stands, primed TNT, falling blocks, projectiles, rockets, tridents),
+once each, in creation order, so check `kind`. A drop, an orb, a mob, a `/summon` and a chunk's entities are told at
+once; other gameplay spawns when the next tick starts, and a cancelled one is removed then. Bundles that use it need `"hooks": 47`.
 
 API 48 adds [a block's items](#a-blocks-items) for server mods, what a pipe or a machine needs to pull from other blocks: `native_container_slots`, `native_extract_item`
 and `native_move_items`, and `native_dimension` for a machine's tick to name its level. `native_insert_item` now goes one item at a time, so it no longer overfills a slot,
@@ -1438,6 +1440,23 @@ For mods that run where the world is simulated: a dedicated server, a LAN host,
   the border. Canceling ends the effect: no
   teleport and no more attempts. Foxes eating chorus fruit are not heard. Bundles need
   `"hooks": @API:chorus_fruit_teleport@`.
+- **`native_player_clone(player, name, was_death)`**: a player's data was copied to their new player (NeoForge's
+  `PlayerEvent.Clone`, from `ServerPlayer.restoreFrom`): after a death respawn (`was_death` true) and when a player
+  leaves the End after the credits (`was_death` false, vanilla's `keepAllPlayerData`). It is heard after the copy and
+  before the new player is placed, once each, on a server. The uuid stays the same, so `player` names the old and the
+  new player alike; no player's state is swapped in, so the helpers that look a player up may find nothing. It cannot
+  stop anything.
+- **`native_player_load_from_file(player, name, directory)`**: a joining player's saved state was read and applied
+  (NeoForge's `PlayerEvent.LoadFromFile`, `PlayerList.loadPlayerData`), before they are placed in a level: once for each
+  join on a server, for an integrated server's owner (loaded from the file `level.dat` names, else their own) as for
+  anyone else. `directory` is the world's `players/data` folder, created if missing; read your own file there, named `<uuid>.<suffix>`. It
+  is heard whether or not the player was in the world before (a new player has no file). No player's state is swapped
+  in. It cannot change or stop anything.
+- **`native_player_save_to_file(player, name, directory)`**: a placed player's data was saved (NeoForge's
+  `PlayerEvent.SaveToFile`, `PlayerList.save`): when they leave or the world closes, when the dedicated server saves
+  everyone, and for an integrated server's owner when the world saves their state into `level.dat`. `directory` is the
+  world's `players/data` folder, created if missing; write your own file there, named `<uuid>.<suffix>`, and never the player's `.dat`.
+  The player may be leaving, so no player's state is swapped in. It cannot change or stop anything.
 - **`native_player_commands_sent(player, name, names)`**: the command tree a player is sent, when they join and when
   their level changes (`/op`, `/deop`, the LAN settings). `names` are the root commands their client would get, vanilla's
   they may use and the mods'; remove a name and that client's tree lacks it, so its chat box neither completes nor
@@ -1468,6 +1487,10 @@ For mods that run where the world is simulated: a dedicated server, a LAN host,
   frame, a painting or a leash knot (tying a lead to a fence that has none; `pos` is the fence), once it fits and
   before it is placed or the item used. Set `cancel` and nothing happens; the item stays in the hand. The player's
   state is swapped in, so `native_tell` answers them. `/summon` and a lead tied to a mob are not heard.
+- **`native_hanging_break(player, kind, pos, cancel)`**: an item frame, a glow item frame or a painting (`kind`)
+  hanging in `pos` is about to break: a server player's hit (`player`, whose state is swapped in), a blast, or the
+  wall it hangs on gone (`player` None for both), before anything drops or sounds. Set `cancel` and it stays as it
+  was. A hit that only takes a frame's item out, the game's own player and `/kill` are not asked.
 - **`native_bucket_empty(player, name, pos, fluid, cancel)`**: a server player empties a bucket (`fluid` is
   `minecraft:water`, `minecraft:lava` or `minecraft:powder_snow`; fish and axolotl buckets pour water) into `pos`,
   right before the fluid is placed. Set `cancel` and nothing is poured. The player's state is swapped in, so
@@ -1483,6 +1506,8 @@ For mods that run where the world is simulated: a dedicated server, a LAN host,
 - **`native_player_edit_book(player, name, pages, signing, cancel)`**: A server player book-and-quill edit or signing packet is about to be applied. `pages` is its page count and `signing` says it has a title. Set `cancel` to drop the packet.
 - **`native_player_shear_entity(player, name, entity_id, off_hand, cancel)`**: A server player is about to shear a sheep, mooshroom, snow golem or bogged. The hook gives the mob entity id and whether the shears are in the off hand. Set `cancel` to leave the mob and shears unchanged.
 - **`native_player_advancement_done(player, name, advancement)`**: A server player completed an advancement after its progress was recorded. `advancement` is its identifier, such as `minecraft:story/mine_stone`; helpers looking up the guest through `self.lan` may find nothing during packet handling.
+- **`native_player_advancement_progress(player, name, advancement, criterion, granted)`**: A criterion of a server player's advancement was granted or revoked, after its progress changed and before any completion rewards, except the `minecraft:tick` criteria granted on a network player's first tick or a reload, which are heard after that tick's rewards and packets. `advancement` is its identifier, such as `minecraft:story/mine_stone`, and `granted` is false for a revoke. A grant or revoke that changes nothing is not heard; helpers looking up the guest through `self.lan` may find nothing during packet handling.
+- **`native_player_stat_award(player, name, stat_type, stat, value, cancel)`**: A statistic is about to be awarded to a server player, before its count and scoreboard criteria change. `stat_type` and `stat` are ids such as `minecraft:mined` and `minecraft:stone`, or `minecraft:custom` and `minecraft:walk_one_cm`, and `value` is the amount. Set `cancel` to award nothing. Helpers looking up the guest through `self.lan` may find nothing during packet handling.
 - **`native_player_riptide(player, name)`**: a server player launched with a riptide trident, after its velocity and spin are applied. The player's state is swapped in, though helpers that look them up through `self.lan` may find nothing during a guest packet.
 - **`native_player_fish(player, name, state, cancel)`**: a player's fishing rod, on a server: `state` 0 the cast, 1 a fish
   biting, 2 the reel-in of a bite (the catch), 3 the reel-in with nothing on the line, 4 the reel-in of a bobber hooked
@@ -2195,7 +2220,7 @@ anything else a mod may change, a game struct or a list, is a `&mut` field. A ca
 the return value; a collection hook's list is a field (`event.lines`). One event goes through every mod, so each
 sees the changes before it. Because no mod can build or match the whole
 struct, a later version can add a field without breaking any mod, as NeoForge's event objects do; the cost is that
-a mod's own tests can't build an event yet.
+a mod's own tests drive a hook through its dispatch function ([Testing a trait mod](#testing-a-trait-mod)).
 
 Hook methods take `&self` and require `Send + Sync`. The process-wide mod list is installed once, like mixin module statics. One mod instance serves both
 the window's game and the server-thread game. A hook can also fire again inside
@@ -2219,6 +2244,29 @@ renderer list is installed once alongside the mod list. `render_needs` collects
 run on the render thread while the frame is built, before any deferred GPU submission.
 The renderer module re-exports the game's wgpu types.
 
+### Testing a trait mod
+
+Every `Host` method defaults to a panic naming it (`not implemented: Host::tell`), so a test double implements
+only what its hook calls, and an unexpected call fails loudly. Drive the hook through
+`horizon_client::mod_api::dispatch_<hook>(&mut host, &mods, args…)`, which builds the event as the game does.
+If a `Host` method returns a game value a test can't build, a double can return `None` instead, as with
+`acting_player() -> Option<NativeServerPlayer>`. If the dispatch function itself takes an unconstructible value,
+such as `dispatch_perform_command`'s `&NativeServerPlayer`, test the logic beneath the hook instead. The level
+hosts are small enough to implement whole. NeoForge's GameTest is the in-game counterpart.
+
+```rust
+struct Stone;
+impl Host for Stone {
+    fn block(&self, _pos: [i32; 3]) -> String {
+        "minecraft:stone".to_string()
+    }
+}
+let mods = [Box::new(MyMod) as Box<dyn Hooks>];
+let mut claimed = false;
+dispatch_use_item_on(&mut Stone, &mods, &stack, [0, 64, 0], [0, 1, 0], &mut claimed);
+assert!(claimed);
+```
+
 ### Adding a hook
 
 A new hook needs its fragment in `tools/native-hook-fragments/` with its `mod_api` entry (for example

docs/server.md

@@ -509,7 +509,10 @@ runtime or new dependency. Server-sent events can replace the polling later if a
   - notifications: the supervisor pushes them to every connected client as vanilla's `JsonRpcNotificationService`
     does (a JSON-RPC request without an `id`, its one parameter in an array), through a queue and a thread so a slow
     client never holds the game's output. Built: `server/started` (the game's `Done`) and `server/stopping`
-    (when the supervisor or the game's own `stop` begins the shutdown, once per run);
+    (when the supervisor or the game's own `stop` begins the shutdown, once per run), `server/saving` and
+    `server/saved` (around every world save of the running game: `save-all`, the autosave, the pause when
+    empty; a save the game makes while it stops is after the last one the supervisor hears of), and
+    `players/joined` and `players/left` (from the game's typed events, within a quarter of a second);
   - planned: `serversettings/*` and `gamerules`, the other notifications and the heartbeat.
 
 ## 9. Benchmark plan (bots against vanilla and Paper)

native-hooks.json

@@ -1758,7 +1758,7 @@
     {
       "name": "menu_slot_rules",
       "version": 1,
-      "target": "horizon_client::menu::native_menu_slot_rules",
+      "target": "horizon_client_lib::menu::native_menu_slot_rules",
       "side": "server",
       "cancellable": false,
       "mod_api": {
@@ -1993,7 +1993,7 @@
     {
       "name": "living_breathe",
       "version": 1,
-      "target": "horizon_client::breathing::native_living_breathe",
+      "target": "horizon_client_lib::breathing::native_living_breathe",
       "neoforge": "LivingBreatheEvent",
       "side": "server",
       "cancellable": false,

tools/native-hook-fragments/native_hanging_break.json

@@ -0,0 +1,16 @@
+{
+  "hooks": [
+    {
+      "name": "hanging_break",
+      "target": "horizon_client::game::native_hooks::Game<'_>::native_hanging_break",
+      "side": "server",
+      "cancellable": true,
+      "mod_api": {
+        "contract": "cancel",
+        "out": "cancel"
+      }
+    }
+  ],
+  "rust_summary": "an item frame or painting about to break, cancellable (`native_hanging_break`).",
+  "doc_summary": "an item frame or painting about to break: `native_hanging_break(player, kind, pos, cancel)` is heard before a server player's hit, a blast or the loss of its wall breaks an item frame, a glow item frame or a painting, with the hitting player (None for a blast or a lost wall). A mod sets `cancel` and it stays. The hitting player's state is swapped in. A hit that only takes a frame's item out, the game's own player and `/kill` are not asked. Bundles that use it need `\"hooks\": @API:native_hanging_break@`."
+}

tools/native-hook-fragments/native_player_clone.json

@@ -0,0 +1,16 @@
+{
+  "hooks": [
+    {
+      "name": "player_clone",
+      "target": "horizon_client::game::native_hooks::Game<'_>::native_player_clone",
+      "neoforge": "PlayerEvent.Clone (not cancellable)",
+      "side": "server",
+      "cancellable": false,
+      "mod_api": {
+        "contract": "listen"
+      }
+    }
+  ],
+  "rust_summary": "a player's data copied to their new player (`native_player_clone`).",
+  "doc_summary": "a player's data copied to their new player: `native_player_clone(player, name, was_death)` is heard from `ServerPlayer.restoreFrom` once for each death respawn (`was_death` true) and for each exit from the End after the credits (`was_death` false), after the retained data is copied and before the new player is placed (NeoForge's `PlayerEvent.Clone`). The uuid stays the same, so `player` names both the old and the new player. It cannot change or stop anything; no player's state is swapped in. Bundles that use it need `\"hooks\": @API:native_player_clone@`."
+}

tools/native-hook-fragments/native_player_load_from_file.json

@@ -0,0 +1,16 @@
+{
+  "hooks": [
+    {
+      "name": "player_load_from_file",
+      "target": "horizon_client::game::native_hooks::Game<'_>::native_player_load_from_file",
+      "neoforge": "PlayerEvent.LoadFromFile (not cancellable)",
+      "side": "server",
+      "cancellable": false,
+      "mod_api": {
+        "contract": "listen"
+      }
+    }
+  ],
+  "rust_summary": "a player loaded from the world's save (`native_player_load_from_file`).",
+  "doc_summary": "a player loaded from the world's save: `native_player_load_from_file(player, name, directory)` is heard once for each join (the owner of an integrated server too), after the player's `.dat` is read and applied and before they are placed in a level (NeoForge's `PlayerEvent.LoadFromFile`, `PlayerList.loadPlayerData`). `directory` is the world's player directory (`players/data`); a mod reads its own file there, named `<uuid>.<suffix>`. It cannot change or stop anything; no player's state is swapped in. Bundles that use it need `\"hooks\": @API:native_player_load_from_file@`."
+}

tools/native-hook-fragments/native_player_save_to_file.json

@@ -0,0 +1,16 @@
+{
+  "hooks": [
+    {
+      "name": "player_save_to_file",
+      "target": "horizon_client::game::native_hooks::Game<'_>::native_player_save_to_file",
+      "neoforge": "PlayerEvent.SaveToFile (not cancellable)",
+      "side": "server",
+      "cancellable": false,
+      "mod_api": {
+        "contract": "listen"
+      }
+    }
+  ],
+  "rust_summary": "a player saved to the world's store (`native_player_save_to_file`).",
+  "doc_summary": "a player saved to the world's store: `native_player_save_to_file(player, name, directory)` is heard once for each save of a placed player (when they leave or the world closes, when the dedicated server saves everyone, and for an integrated server's owner when the world saves them; LAN guests are not heard on integrated autosaves) after their data is written (NeoForge's `PlayerEvent.SaveToFile`, `PlayerList.save`). `directory` is the world's player directory (`players/data`); write your own file there, named `<uuid>.<suffix>`, never the player's `.dat`. The player may be leaving, so no player's state is swapped in. It cannot change or stop anything. Bundles that use it need `\"hooks\": @API:native_player_save_to_file@`."
+}

tools/native-hook-fragments/player_advancement_progress.json

@@ -0,0 +1,16 @@
+{
+  "hooks": [
+    {
+      "name": "player_advancement_progress",
+      "target": "horizon_client::game::native_hooks::Game<'_>::native_player_advancement_progress",
+      "side": "server",
+      "neoforge": "AdvancementEvent.AdvancementProgressEvent",
+      "cancellable": false,
+      "mod_api": {
+        "contract": "listen"
+      }
+    }
+  ],
+  "rust_summary": "A criterion of a server player's advancement was granted or revoked (`native_player_advancement_progress`).",
+  "doc_summary": "A criterion of a server player's advancement was granted or revoked after its progress changed and before any completion rewards, except the `minecraft:tick` criteria granted on a network player's first tick or a reload, which are heard after that tick's rewards and packets; `advancement` is its identifier, such as `minecraft:story/mine_stone`, `criterion` the criterion name and `granted` is false for a revoke. A grant or revoke that changes nothing is not heard. Helpers looking up the guest through `self.lan` may find nothing during packet handling. Bundles need \"hooks\": @API:player_advancement_progress@."
+}

tools/native-hook-fragments/player_stat_award.json

@@ -0,0 +1,17 @@
+{
+  "hooks": [
+    {
+      "name": "player_stat_award",
+      "target": "horizon_client::game::native_hooks::Game<'_>::native_player_stat_award",
+      "side": "server",
+      "neoforge": "StatAwardEvent",
+      "cancellable": true,
+      "mod_api": {
+        "contract": "cancel",
+        "out": "cancel"
+      }
+    }
+  ],
+  "rust_summary": "A statistic about to be awarded to a server player, cancellable (`native_player_stat_award`).",
+  "doc_summary": "A statistic about to be awarded to a server player: `native_player_stat_award(player, name, stat_type, stat, value, cancel)`, with `stat_type` such as `minecraft:mined` or `minecraft:custom`, `stat` such as `minecraft:stone` or `minecraft:walk_one_cm`, and `value` the amount added. Set `cancel` to award nothing: the count and its scoreboard criteria stay as they were. Helpers looking up the guest through `self.lan` may find nothing during packet handling. Bundles need \"hooks\": @API:player_stat_award@."
+}

tools/port_map/game-011.tsv

@@ -17,7 +17,7 @@ AbstractHorse.fedFood	port	crates/horizon-client/src/game/mounts.rs::Game::feed_
 AbstractHorse.doPlayerRide	inline	crates/horizon-client/src/game/mounts.rs::Game::interact_mount	clears eating and standing, turns the player to the mount and mounts; the block at the end of interact_mount
 AbstractHorse.isImmobile	port	crates/horizon-client/src/mobs/equine.rs::immobile	
 AbstractHorse.dropEquipment	inline	crates/horizon-client/src/mobs/drops.rs::die	the equine branch drops the inventory items and a donkey's or mule's chest
-AbstractHorse.followMommy	missing		minor: no Bred flag, so a bred foal is not pulled to its mother from 16 blocks; the FollowParent goal covers 8
+AbstractHorse.followMommy	inline	crates/horizon-client/src/mobs/equine.rs::ai_step	follow_mommy: a bred foal that is not eating keeps a path to the nearest bred AbstractHorse within 16 blocks and more than 2 away (createPath(entity, 0), which leaves the speed modifier alone); Bred is NBT-only in 26.3, so only a save or a summon gives it
 AbstractHorse.openMouth	inline	crates/horizon-client/src/game/mounts.rs::Game::feed_mount	gap: minor: sets the mouth animation to 1 once, it closes after 3 ticks; the mouth flag is not synced to a remote client
 AbstractHorse.setStanding	inline	crates/horizon-client/src/mobs/equine.rs::make_mad	the 20 tick rear; RandomStand::start and the jump in tick_mount_riding set the same counter
 AbstractHorse.standIfPossible	inline	crates/horizon-client/src/mobs/equine.rs::make_mad	rears only species that can; the hurt caller is missing (see hurtServer)
@@ -129,7 +129,7 @@ AbstractSchoolingFish.addFollowers	inline	crates/horizon-client/src/mobs/aquatic
 AbstractSchoolingFish.finalizeSpawn	inline	crates/horizon-client/src/mobs/finalize.rs::Ctx::finalize	the group shares a leader id and variant, and FollowFlockLeader (crates/horizon-client/src/mobs/aquatic.rs) paths a follower to the leader every 10 ticks
 Pufferfish.readAdditionalSaveData	port	crates/horizon-client/src/entity_nbt.rs::mob_from_nbt	`getIntOr("PuffState", 0)` at most 2; mob_to_nbt writes it, and a reload test covers it
 Pufferfish.registerGoals	port	crates/horizon-client/src/mobs/aquatic.rs::register	the puff goal at priority 1
-Pufferfish.touch	missing		minor: only the player is stung (inside ai_step); other mobs touching a puffed fish are not hurt or poisoned
+Pufferfish.touch	inline	crates/horizon-client/src/mobs/aquatic.rs::ai_step	sting_touching_mobs: alive mobs outside #not_scary_for_pufferfish whose box meets the fish's inflated by 0.3, when teams allow damage, take a mobAttack hit for puff state + 1, then, once it lands, POISON for 60 * puff state and the sting sound (game/creatures.rs PufferfishSting)
 Salmon.defineSynchedData	port	crates/horizon-client/src/game/lan.rs::mob_meta	size entry, small 0 to large 2
 Salmon.readAdditionalSaveData	port	crates/horizon-client/src/entity_nbt.rs::read_variant	the type tag, medium by default
 Salmon.get	inline	crates/horizon-client/src/entity_nbt.rs::bucket_components	the size component goes onto the bucket

tools/port_map/rest-013.tsv

@@ -110,8 +110,8 @@ MinecraftServer.createProfiler	skip:server		profiler setup
 MinecraftServer.startRecordingMetrics	skip:server		metrics recording for the profiler
 MinecraftServer.createGameModeForPlayer	missing		minor: demo mode is not implemented; --demo is accepted and ignored (dedicated.rs preflight)
 MinecraftServer.stopTimeProfiler	skip:debug		debug profiler stop
-MinecraftServer.setAutoSave	inline	crates/horizon-client/src/game/dedicated.rs::Game::console_command	gap: minor: the save-on/save-off flag is kept, but the tick's autosave does not read it
-MinecraftServer.isAutoSave	inline	crates/horizon-client/src/game/dedicated.rs::Game::console_command	reads the same flag for the save-on reply only
+MinecraftServer.setAutoSave	port	crates/horizon-client/src/game/dedicated.rs::set_auto_save	changes the shared server-level save flag; the tick skips periodic saves while it is disabled
+MinecraftServer.isAutoSave	port	crates/horizon-client/src/game/dedicated.rs::auto_save	reads the shared server-level save flag
 MinecraftServer.storeChunkIoError	skip:debug		writes a chunk IO crash report
 MinecraftServer.reportChunkLoadFailure	missing		unsure: no chunk-load failure log or report found in save.rs or streaming.rs
 MinecraftServer.reportChunkSaveFailure	port	crates/horizon-client/src/save.rs::Persistent::save_finished	gap: minor: logs only; no debug report and no low-disk warning

tools/port_map/rest-017.tsv

@@ -25,6 +25,7 @@ DedicatedServer.setEntityBroadcastRangePercentage	skip:server		JSON-RPC manageme
 DedicatedServer.createTextFilterForPlayer	skip:service		external chat filter service; Horizon has no text filter
 DedicatedServer.setForceGameMode	port	crates/horizon-client/src/game/dedicated/management.rs::Game::management	stores force-gamemode, updates the host and applies the default mode to online players
 MinecraftServerSettingsServiceImpl.setForceGameMode	port	crates/horizon-server/src/management_methods.rs::Game::force_game_mode	forwards the live setting to the game and persists it in server.toml
+MinecraftServerSettingsServiceImpl.setAutoSave	port	crates/horizon-server/src/management_methods.rs::Game::autosave	forwards the live save flag to the game; unlike a server property, it resets when the server restarts
 DedicatedServer.setGameMode	port	crates/horizon-client/src/game/lan.rs::Game::set_default_game_mode	the /defaultgamemode command; gap: minor: the value is not written back to server.properties
 DedicatedServer.setAcceptsTransfers	skip:server		JSON-RPC management API only (ServerSettingsService); Horizon has no such API
 DedicatedServer.setPauseWhenEmptySeconds	skip:server		JSON-RPC management API only (ServerSettingsService); Horizon has no such API

tools/test_management_protocol_parity.py

@@ -16,7 +16,8 @@ sent the same things over TLS, and every answer is compared exactly:
   vanilla's data generator), `server/status`, the four lists, `players`, kicking nobody, `server/save` and
   `server/system_message` with no one online, the four lists changed (`add`, `remove`, `set`,
   `clear`; with no profile service, players named resolve to offline players on both), the live server
-  message, difficulty, default game mode and forced game mode read and changed (including saved properties), and
+  message, difficulty, default and forced game mode read and changed (including saved properties), autosave
+  read and changed (including its reset after restart), and
   `server/stop`;
 - the TLS version each server agrees on.
 
@@ -148,6 +149,15 @@ MESSAGES = [
     '{"jsonrpc":"2.0","id":61,"method":"minecraft:serversettings/force_game_mode"}',
     '{"jsonrpc":"2.0","id":62,"method":"minecraft:serversettings/force_game_mode/set","params":["yes"]}',
     '{"jsonrpc":"2.0","id":63,"method":"minecraft:serversettings/force_game_mode"}',
+    '{"jsonrpc":"2.0","id":65,"method":"minecraft:serversettings/autosave"}',
+    '{"jsonrpc":"2.0","id":66,"method":"minecraft:serversettings/autosave/set","params":[false]}',
+    '{"jsonrpc":"2.0","id":67,"method":"minecraft:serversettings/autosave"}',
+    '{"jsonrpc":"2.0","id":68,"method":"minecraft:serversettings/autosave/set","params":[true]}',
+    '{"jsonrpc":"2.0","id":69,"method":"minecraft:serversettings/autosave"}',
+    '{"jsonrpc":"2.0","id":70,"method":"minecraft:serversettings/autosave/set","params":[false]}',
+    '{"jsonrpc":"2.0","id":71,"method":"minecraft:serversettings/autosave"}',
+    '{"jsonrpc":"2.0","id":72,"method":"minecraft:serversettings/autosave/set","params":["yes"]}',
+    '{"jsonrpc":"2.0","id":73,"method":"minecraft:serversettings/autosave"}',
 ]
 
 
@@ -392,6 +402,12 @@ def main():
                         if not isinstance(reply, dict) or 'method' not in reply or 'id' in reply:
                             break
                     sides[side]['restarted_force_game_mode'] = reply
+                    ws.send('{"jsonrpc":"2.0","id":74,"method":"minecraft:serversettings/autosave"}')
+                    while True:
+                        reply = normal(ws.receive(timeout=60))
+                        if not isinstance(reply, dict) or 'method' not in reply or 'id' in reply:
+                            break
+                    sides[side]['restarted_autosave'] = reply
                 finally:
                     ws.sock.close()
             finally:
@@ -419,6 +435,9 @@ def main():
         if vanilla['restarted_force_game_mode'] != horizon['restarted_force_game_mode'] or \
                 vanilla['restarted_force_game_mode'] != {'jsonrpc': '2.0', 'id': 64, 'result': True}:
             failures.append(f"restarted forced game mode: vanilla {vanilla['restarted_force_game_mode']!r}, Horizon {horizon['restarted_force_game_mode']!r}")
+        if vanilla['restarted_autosave'] != horizon['restarted_autosave'] or \
+                vanilla['restarted_autosave'] != {'jsonrpc': '2.0', 'id': 74, 'result': True}:
+            failures.append(f"restarted autosave: vanilla {vanilla['restarted_autosave']!r}, Horizon {horizon['restarted_autosave']!r}")
         (build / 'report.json').write_text(json.dumps(sides, indent=1))
         if failures:
             sys.exit(f'{NAME}: {len(failures)} differences (logs in {build}):\n' + '\n'.join(failures))

xtask/src/mod_api.rs

@@ -280,8 +280,15 @@ fn host_method(
         args.push(pat.ident.to_string());
     }
     let docs = doc_comments(&method.attrs, name, true)?;
+    let unused = args
+        .iter()
+        .map(|arg| format!("let _ = {arg};"))
+        .collect::<String>();
     Ok((
-        format!("{docs}{};\n", sig.to_token_stream()),
+        format!(
+            "{docs}{} {{ {unused} unimplemented!(\"Host::{name}\") }}\n",
+            sig.to_token_stream()
+        ),
         format!(
             "{} {{ {callee}{original}({}) }}\n",
             sig.to_token_stream(),
@@ -964,7 +971,7 @@ fn generate(root: &Path, check: bool) -> Result<(), String> {
         imports.push_str("use std::sync::Arc;\n");
     }
     let host = format!(
-        "// @generated by cargo run -p xtask -- mod-api; do not edit.\nuse super::*;\n{imports}/// Services supplied by the game to trait mods.\npub trait Host {{\n{host_traits}}}\n"
+        "// @generated by cargo run -p xtask -- mod-api; do not edit.\nuse super::*;\n{imports}/// Services supplied by the game to trait mods.\n/// Each method's default panics with its name, so a test double implements only what its test calls; the game implements every one.\npub trait Host {{\n{host_traits}}}\n"
     );
     let implementation = format!(
         "// @generated by cargo run -p xtask -- mod-api; do not edit.\nuse horizon_client::mod_api::*;\n{imports}impl Host for super::Game<'_> {{\n{host_impl}}}\n"