Pour a refused water bucket beside the clicked block

BucketItem.emptyContents retries at the block beside the clicked face
when the clicked block refuses the fluid. Without it, a water bucket on
a double slab did nothing, and a sneak-click on a waterloggable block
failed instead of pouring next to it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/horizon-client/src/game.rs

@@ -13048,18 +13048,25 @@ impl Game<'_> {
                 return Ok(UseResult::Fail);
             }
             let pos = BlockPos::new(target[0], target[1], target[2]);
+            let beside = BlockPos::new(
+                hit.pos[0] + hit.face[0],
+                hit.pos[1] + hit.face[1],
+                hit.pos[2] + hit.face[2],
+            );
             // `Player.isShiftKeyDown`: only air takes a fluid under Shift.
             let sneaking = self.keys.contains(&KeyCode::ShiftLeft);
             let creative = self.creative;
             let emptied = self.with_level(|b, level, ticks| {
-                b.bucket_empty(level, ticks, pos, content, sound, sneaking, creative)
+                b.bucket_empty_beside(
+                    level, ticks, pos, beside, content, sound, sneaking, creative,
+                )
             });
             self.process_level_events()?;
-            if !emptied {
+            let Some(emptied) = emptied else {
                 return Ok(UseResult::Fail);
-            }
+            };
             if self.dim == Dim::Nether && content.is_water() {
-                self.evaporation_smoke(target);
+                self.evaporation_smoke([emptied.x, emptied.y, emptied.z]);
             }
             // `BucketItem.emptyContents` uses `playSound(player, …)`: the
             // actor's client already played the empty / evaporate sound from

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

@@ -7652,18 +7652,26 @@ impl Game<'_> {
         };
         let target = self.bucket_target(content, &hit);
         let pos = horizon_core::position::BlockPos::new(target[0], target[1], target[2]);
+        let beside = horizon_core::position::BlockPos::new(
+            hit.pos[0] + hit.face[0],
+            hit.pos[1] + hit.face[1],
+            hit.pos[2] + hit.face[2],
+        );
         let sneaking = self.keys.contains(&KeyCode::ShiftLeft);
         let creative = self.creative;
-        // A water bucket on a liquid container fills it server-side only.
+        // A water bucket on a liquid container fills it server-side only;
+        // a container that refuses passes it to the block beside, which
+        // this client changes itself.
         let clicked = self.world.block(hit.pos[0], hit.pos[1], hit.pos[2]);
-        let client_change =
-            !(content.is_water() && self.res.behaviours().is_liquid_container(clicked));
+        let container = content.is_water() && self.res.behaviours().is_liquid_container(clicked);
         self.with_level(|b, level, ticks| {
             let mut level = DryLevel::new(level);
-            let emptied =
-                b.bucket_empty(&mut level, ticks, pos, content, sound, sneaking, creative);
+            let emptied = b.bucket_empty_beside(
+                &mut level, ticks, pos, beside, content, sound, sneaking, creative,
+            );
+            let client_change = !(container && emptied == Some(pos));
             (
-                emptied,
+                emptied.is_some(),
                 client_change.then(|| level.changed.into_iter().collect()),
                 std::mem::take(&mut level.sounds),
             )

crates/horizon-world/src/level/buckets.rs

@@ -60,18 +60,22 @@ impl<L: LevelAccess + ?Sized> Sim<'_, L> {
         };
         self.pickup_block(pos, state, creative).then_some(item)
     }
-    /// `BucketItem.emptyContents(user, level, pos, hitResult)`. `sound` is the
-    /// bucket's empty sound (mob buckets have their own); `sneaking` is
+    /// `BucketItem.emptyContents(user, level, pos, hitResult)`: where the
+    /// contents went, None when nothing was emptied. `beside` is
+    /// `hitResult.getBlockPos().relative(hitResult.getDirection())` (None for
+    /// a dispenser, which has no hit result). `sound` is the bucket's empty
+    /// sound (mob buckets have their own); `sneaking` is
     /// `user.isShiftKeyDown()` (false for a dispenser, whose user is null);
     /// `creative` is whether that user is a creative player.
     pub(crate) fn bucket_empty(
         &mut self,
         pos: BlockPos,
+        beside: Option<BlockPos>,
         content: BucketContent,
         sound: &str,
         sneaking: bool,
         creative: bool,
-    ) -> bool {
+    ) -> Option<BlockPos> {
         let b = self.b;
         let fluid = match content {
             BucketContent::Powder => {
@@ -82,14 +86,14 @@ impl<L: LevelAccess + ?Sized> Sim<'_, L> {
                     self.game_event(pos, "minecraft:fluid_place");
                     let sound: Arc<str> = sound.into();
                     self.sound(pos, &sound, 1.0, 1.0);
-                    return true;
+                    return Some(pos);
                 }
-                return false;
+                return None;
             }
             BucketContent::Nothing => {
                 let sound: Arc<str> = sound.into();
                 self.sound(pos, &sound, 1.0, 1.0);
-                return true;
+                return Some(pos);
             }
             BucketContent::MobWater => FluidKind::Water,
             BucketContent::Fluid(fluid) => fluid,
@@ -108,7 +112,12 @@ impl<L: LevelAccess + ?Sized> Sim<'_, L> {
         // when the player is not sneaking (a dispenser has no user and so
         // no hit result, which always allows it).
         if !(b.is_air(state) || place_liquid && !sneaking) {
-            return false;
+            // A refused click (a double slab, or Shift on a waterloggable
+            // block) pours into the block beside the clicked face instead,
+            // without a hit result, so Shift no longer matters there.
+            return beside.and_then(|beside| {
+                self.bucket_empty(beside, None, content, sound, false, creative)
+            });
         }
         let water = matches!(fluid, FluidKind::Water | FluidKind::FlowingWater);
         if water && self.level.dimension() == Dimension::Nether {
@@ -120,7 +129,7 @@ impl<L: LevelAccess + ?Sized> Sim<'_, L> {
                 volume: 0.5,
                 pitch,
             });
-            return true;
+            return Some(pos);
         }
         if liquid_container && water {
             self.place_liquid(
@@ -130,7 +139,7 @@ impl<L: LevelAccess + ?Sized> Sim<'_, L> {
                 creative,
             );
             self.empty_sound(pos, sound, mob);
-            return true;
+            return Some(pos);
         }
         if may_replace && !b.instance_of(state, Class::Liquid) {
             self.destroy_block(pos, true, super::flags::UPDATE_LIMIT);
@@ -148,10 +157,10 @@ impl<L: LevelAccess + ?Sized> Sim<'_, L> {
         if !self.set_block(pos, legacy, super::flags::UPDATE_ALL_IMMEDIATE)
             && !self.fluid_at(pos).is_source()
         {
-            return false;
+            return None;
         }
         self.empty_sound(pos, sound, mob);
-        true
+        Some(pos)
     }
     /// `playEmptySound`: `MobBucketItem` overrides it without the game event.
     fn empty_sound(&mut self, pos: BlockPos, sound: &str, mob: bool) {
@@ -175,7 +184,7 @@ impl Behaviours {
     ) -> Option<&'static str> {
         self.sim(level, ticks).bucket_pickup(pos, creative)
     }
-    /// `DispensibleContainerItem.emptyContents(user, level, pos, hitResult)`.
+    /// `DispensibleContainerItem.emptyContents(user, level, pos, null)`.
     pub fn bucket_empty<L: LevelAccess + ?Sized>(
         &self,
         level: &mut L,
@@ -187,6 +196,24 @@ impl Behaviours {
         creative: bool,
     ) -> bool {
         self.sim(level, ticks)
-            .bucket_empty(pos, content, sound, sneaking, creative)
+            .bucket_empty(pos, None, content, sound, sneaking, creative)
+            .is_some()
+    }
+    /// `BucketItem.emptyContents(user, level, pos, hitResult)` for a click:
+    /// `beside` is the block beside the clicked face, tried when `pos`
+    /// refuses. Returns where the contents went.
+    pub fn bucket_empty_beside<L: LevelAccess + ?Sized>(
+        &self,
+        level: &mut L,
+        ticks: &mut Ticks,
+        pos: BlockPos,
+        beside: BlockPos,
+        content: BucketContent,
+        sound: &str,
+        sneaking: bool,
+        creative: bool,
+    ) -> Option<BlockPos> {
+        self.sim(level, ticks)
+            .bucket_empty(pos, Some(beside), content, sound, sneaking, creative)
     }
 }

crates/horizon-world/src/level/tests.rs

@@ -2295,6 +2295,44 @@ fn dispenser_buckets_pick_up_and_empty() {
             .bucket_empty(&mut w.level, &mut w.ticks, at, content, sound, true, false)
     );
     assert_eq!(w.prop(at, "waterlogged"), "false");
+    // A click on the slab pours beside it, where Shift no longer matters.
+    let above = BlockPos::new(at.x, at.y + 1, at.z);
+    assert_eq!(
+        w.b().bucket_empty_beside(
+            &mut w.level,
+            &mut w.ticks,
+            at,
+            above,
+            content,
+            sound,
+            true,
+            false
+        ),
+        Some(above)
+    );
+    assert_eq!(w.prop(at, "waterlogged"), "false");
+    assert_eq!(w.name(above), "water[level=0]");
+    // A double slab holds no water: the click fills the block beside it.
+    let air = w.b().air();
+    w.put(above, air);
+    let double = w.id("oak_slab", &[("type", "double")]);
+    w.put(at, double);
+    assert_eq!(
+        w.b().bucket_empty_beside(
+            &mut w.level,
+            &mut w.ticks,
+            at,
+            above,
+            content,
+            sound,
+            false,
+            false
+        ),
+        Some(above)
+    );
+    assert_eq!(w.prop(at, "type"), "double");
+    assert_eq!(w.name(above), "water[level=0]");
+    w.put(above, air);
     // Powder snow only goes into empty space.
     let air = w.b().air();
     w.put(at, air);