fix(core): 🐛 MixBuiltin does not currently support merging.

This limitation exists because even though multiple `MixBuiltin` can be attached to the same widget, they may have different lifetimes. For instance, in the case of MixBuiltin(Pipe(MixBuiltin)), the outer `MixBuiltin` should outlive the inner one.

CHANGELOG.md

@@ -30,6 +30,11 @@ Please only add new entries below the [Unreleased](#unreleased---releasedate) he
 - **core**: Setting the theme before running the app results in the tree being constructed twice. (#637, @M-Adoo)
 - **core**: Resolve a crash occurring in a class implementation with multiple children. (#637 @M-Adoo)
 - **core**: Nodes created by a class implementation may not be disposed of when switching to another class. (#637 @M-Adoo)
+- **core**: When merge multiple `MixBuiltin` widgets, there may be a premature dropping of the outer `MixBuiltin` before it should occur. (#639 @M-Adoo)
+
+### Breaking
+
+- **macros**: Using `@ $w { ... }` will no longer automatically wrap a `FatObj` for `w`. (#639 @M-Adoo)
 
 ## [0.4.0-alpha.12] - 2024-10-09
 

core/src/builtin_widgets.rs

@@ -110,25 +110,25 @@ pub struct FatObj<T> {
   host: T,
   host_id: LazyWidgetId,
   id: LazyWidgetId,
-  mix_builtin: Option<MixBuiltin>,
-  request_focus: Option<State<RequestFocus>>,
+  padding: Option<State<Padding>>,
   fitted_box: Option<State<FittedBox>>,
+  constrained_box: Option<State<ConstrainedBox>>,
   box_decoration: Option<State<BoxDecoration>>,
   foreground: Option<State<Foreground>>,
-  padding: Option<State<Padding>>,
+  scrollable: Option<State<ScrollableWidget>>,
   layout_box: Option<State<LayoutBox>>,
+  mix_builtin: Option<MixBuiltin>,
+  request_focus: Option<State<RequestFocus>>,
   cursor: Option<State<Cursor>>,
   margin: Option<State<Margin>>,
-  scrollable: Option<State<ScrollableWidget>>,
-  constrained_box: Option<State<ConstrainedBox>>,
   transform: Option<State<TransformWidget>>,
+  opacity: Option<State<Opacity>>,
+  visibility: Option<State<Visibility>>,
+  class: Option<State<Class>>,
   h_align: Option<State<HAlignWidget>>,
   v_align: Option<State<VAlignWidget>>,
   relative_anchor: Option<State<RelativeAnchor>>,
   global_anchor: Option<State<GlobalAnchor>>,
-  visibility: Option<State<Visibility>>,
-  opacity: Option<State<Opacity>>,
-  class: Option<State<Class>>,
   painting_style: Option<State<PaintingStyleWidget>>,
   text_style: Option<State<TextStyleWidget>>,
   keep_alive: Option<State<KeepAlive>>,
@@ -170,7 +170,6 @@ impl<T> FatObj<T> {
 
   /// Maps an `FatObj<T>` to `FatObj<V>` by applying a function to the host
   /// object.
-  #[track_caller]
   pub fn map<V>(self, f: impl FnOnce(T) -> V) -> FatObj<V> {
     FatObj {
       host: f(self.host),
@@ -216,6 +215,7 @@ impl<T> FatObj<T> {
       && self.cursor.is_none()
       && self.margin.is_none()
       && self.scrollable.is_none()
+      && self.constrained_box.is_none()
       && self.transform.is_none()
       && self.h_align.is_none()
       && self.v_align.is_none()
@@ -941,8 +941,8 @@ impl<'a> FatObj<Widget<'a>> {
           cursor,
           margin,
           transform,
-          visibility,
           opacity,
+          visibility,
           class,
           h_align,
           v_align,

core/src/builtin_widgets/class.rs

@@ -351,7 +351,7 @@ mod tests {
     let mut theme = Theme::default();
     theme
       .classes
-      .insert(MARGIN, |w| fn_widget! { @ $w{ margin: EdgeInsets::all(10.) } }.into_widget());
+      .insert(MARGIN, style_class!(margin: EdgeInsets::all(10.)));
     theme.classes.insert(SCALE_2X, |w| {
       fn_widget! {
         @MockBox {

core/src/builtin_widgets/cursor.rs

@@ -18,7 +18,8 @@ impl<'c> ComposeChild<'c> for Cursor {
   fn compose_child(this: impl StateWriter<Value = Self>, child: Self::Child) -> Widget<'c> {
     fn_widget! {
       let save_cursor: Stateful<Option<CursorIcon>> = Stateful::new(None);
-      @$child {
+      let child = FatObj::new(child);
+      @ $child {
         on_pointer_enter: move |e: &mut PointerEvent| {
           if e.point_type == PointerType::Mouse
             && e.mouse_buttons() == MouseButtons::empty()

core/src/builtin_widgets/focus_node.rs

@@ -15,7 +15,8 @@ impl<'c> ComposeChild<'c> for RequestFocus {
   type Child = Widget<'c>;
   fn compose_child(this: impl StateWriter<Value = Self>, child: Self::Child) -> Widget<'c> {
     fn_widget! {
-      @$child {
+      let child = FatObj::new(child);
+      @ $child {
         on_mounted: move |e| {
           let handle = e.window().focus_mgr.borrow().focus_handle(e.id);
           $this.silent().handle = Some(handle);
@@ -51,18 +52,12 @@ mod tests {
     reset_test_env!();
 
     let widget = fn_widget! {
-      @MixBuiltin {
-        tab_index: 0i16, auto_focus: false,
-        @MixBuiltin {
-          tab_index: 0i16, auto_focus: false,
-          @MixBuiltin {
-            tab_index: 0i16, auto_focus: false,
-            @MockBox {
-              size: Size::default(),
-            }
-          }
-        }
-      }
+      let m = @MockBox {
+        tab_index: 0i16,
+        size: Size::default(),
+      };
+      let m = @ $m { tab_index: 0i16, };
+      @ $m { tab_index: 0i16 }
     };
 
     let wnd = TestWindow::new(widget);

core/src/builtin_widgets/focus_scope.rs

@@ -18,6 +18,7 @@ impl<'c> ComposeChild<'c> for FocusScope {
   type Child = Widget<'c>;
   fn compose_child(this: impl StateWriter<Value = Self>, child: Self::Child) -> Widget<'c> {
     fn_widget! {
+      let child = FatObj::new(child);
       @ $child {
         on_mounted: move |e| e.window().add_focus_node(e.id, false, FocusType::Scope),
         on_disposed: move|e| e.window().remove_focus_node(e.id, FocusType::Scope),

core/src/builtin_widgets/global_anchor.rs

@@ -20,7 +20,7 @@ impl<'c> ComposeChild<'c> for GlobalAnchor {
         .frame_tick_stream()
         .filter(|msg| matches!(msg, FrameMsg::LayoutReady(_)));
 
-      let mut child = @$child {};
+      let mut child = FatObj::new(child);
       let wid = child.lazy_id();
       let u = watch!(($this.get_global_anchor(), $child.layout_size()))
         .sample(tick_of_layout_ready)

core/src/builtin_widgets/layout_box.rs

@@ -17,14 +17,12 @@ impl<'c> ComposeChild<'c> for LayoutBox {
   type Child = Widget<'c>;
   fn compose_child(this: impl StateWriter<Value = Self>, child: Self::Child) -> Widget<'c> {
     fn_widget! {
-      @ $child {
-        on_performed_layout: move |e| {
-          let new_rect = e.box_rect().unwrap();
-          if $this.rect != new_rect {
-            $this.silent().rect = new_rect;
-          }
+      FatObj::new(child).on_performed_layout(move |e| {
+        let new_rect = e.box_rect().unwrap();
+        if $this.rect != new_rect {
+          $this.silent().rect = new_rect;
         }
-      }
+      })
     }
     .into_widget()
   }

core/src/builtin_widgets/mix_builtin.rs

@@ -126,7 +126,11 @@ impl MixFlags {
     }
   }
 
-  pub fn tab_index(&self) -> i16 { (self.bits() >> 48) as i16 }
+  pub fn tab_index(&self) -> Option<i16> {
+    self
+      .contains(MixFlags::Focus)
+      .then(|| (self.bits() >> 48) as i16)
+  }
 
   pub fn set_tab_index(&mut self, tab_idx: i16) {
     self.insert(MixFlags::Focus);
@@ -354,45 +358,12 @@ impl MixBuiltin {
     }
   }
 
-  fn merge(&self, other: Self) {
-    let tab_index = self.flags.read().tab_index();
-    let other_tab_index = other.flags.read().tab_index();
-    let mut this_flags = self.flags.write();
-    this_flags.insert(*other.flags.read());
-    if other_tab_index != 0 {
-      this_flags.set_tab_index(other_tab_index);
-    } else if tab_index != 0 {
-      this_flags.set_tab_index(tab_index);
-    }
-    drop(this_flags);
-    let Self { flags, subject } = other;
-
-    // if the other `MixFlags` is a writer, we need to subscribe it.
-    if let Err(other) = flags.into_reader() {
-      let this_flags = self.flags.clone_writer();
-      let u = other
-        .modifies()
-        .distinct_until_changed()
-        .subscribe(move |_| {
-          let flags = *other.read();
-          let mut this = this_flags.write();
-          this.insert(flags);
-          this.set_tab_index(flags.tab_index());
-        });
-      self.on_disposed(|_| u.unsubscribe());
-    }
-
-    fn subscribe_fn(subject: EventSubject) -> impl FnMut(&mut Event) {
-      move |e: &mut Event| subject.clone().next(e)
-    }
-    self.subject().subscribe(subscribe_fn(subject));
-  }
-
   fn callbacks_for_focus_node(&self) {
     self
       .on_mounted(move |e| {
-        if let Some(mix) = e.query::<MixBuiltin>() {
-          let auto_focus = mix.flags.read().is_auto_focus();
+        let mut all_mix = e.query_all_iter::<MixBuiltin>().peekable();
+        if all_mix.peek().is_some() {
+          let auto_focus = all_mix.any(|mix| mix.flags.read().is_auto_focus());
           e.window()
             .add_focus_node(e.id, auto_focus, FocusType::Node)
         }
@@ -428,27 +399,10 @@ fn life_fn_once_to_fn_mut(
 impl<'c> ComposeChild<'c> for MixBuiltin {
   type Child = Widget<'c>;
   fn compose_child(this: impl StateWriter<Value = Self>, child: Self::Child) -> Widget<'c> {
-    child.on_build(move |id, ctx| match this.try_into_value() {
-      Ok(this) => {
-        if let Some(m) = id.query_ref::<MixBuiltin>(ctx.tree()) {
-          if !m.contain_flag(MixFlags::Focus) && this.contain_flag(MixFlags::Focus) {
-            this.callbacks_for_focus_node();
-          }
-          m.merge(this);
-        } else {
-          if this.contain_flag(MixFlags::Focus) {
-            this.callbacks_for_focus_node();
-          }
-          id.attach_data(Box::new(Queryable(this)), ctx.tree_mut());
-        }
-      }
-      Err(this) => {
-        if this.read().contain_flag(MixFlags::Focus) {
-          this.read().callbacks_for_focus_node();
-        }
-        id.attach_data(Box::new(this), ctx.tree_mut())
-      }
-    })
+    if this.read().contain_flag(MixFlags::Focus) {
+      this.read().callbacks_for_focus_node();
+    }
+    child.try_unwrap_state_and_attach(this)
   }
 }
 
@@ -507,3 +461,37 @@ impl Clone for MixBuiltin {
     Self { flags, subject: self.subject.clone() }
   }
 }
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use crate::{reset_test_env, test_helper::*};
+
+  #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+  #[test]
+  fn mix_should_not_merge() {
+    reset_test_env!();
+
+    let (trigger, w_trigger) = split_value(0);
+    let (outer_layout, w_outer_layout) = split_value(0);
+    let mix_keep = fn_widget! {
+      let pipe_w = FatObj::new( pipe! {
+        $trigger;
+        @Void { on_performed_layout: move |_| {} }
+      });
+
+      @ $pipe_w {
+        on_performed_layout: move |_| *$w_outer_layout.write() +=1 ,
+      }
+    };
+
+    let mut wnd = TestWindow::new(mix_keep);
+    wnd.draw_frame();
+    assert_eq!(*outer_layout.read(), 1);
+
+    *w_trigger.write() = 1;
+
+    wnd.draw_frame();
+    assert_eq!(*outer_layout.read(), 2);
+  }
+}

core/src/builtin_widgets/scrollable.rs

@@ -45,6 +45,7 @@ impl<'c> ComposeChild<'c> for ScrollableWidget {
         clamp_dim: ClampDim::MAX_SIZE,
       };
 
+      let child = FatObj::new(child);
       let mut child = @ $child {
         anchor: pipe!{
           let this = $this;

core/src/context/widget_ctx.rs

@@ -66,6 +66,9 @@ pub trait WidgetCtx {
   /// Translates the widget pos from the coordinate system of `w` to this widget
   /// system.
   fn map_from(&self, pos: Point, w: WidgetId) -> Point;
+  /// Query all references to the `T` if it is shared within the widget
+  /// represented by this context.
+  fn query_all_iter<T: 'static>(&self) -> impl DoubleEndedIterator<Item = QueryRef<T>>;
   /// Query a reference to the `T` if it is shared within the widget
   /// represented by this context.
   ///
@@ -182,7 +185,10 @@ impl<T: WidgetCtxImpl> WidgetCtx for T {
     self.map_from_global(global)
   }
 
-  #[inline]
+  fn query_all_iter<Q: 'static>(&self) -> impl DoubleEndedIterator<Item = QueryRef<Q>> {
+    self.id().query_all_iter(self.tree())
+  }
+
   fn query<Q: 'static>(&self) -> Option<QueryRef<Q>> { self.query_of_widget::<Q>(self.id()) }
 
   #[inline]

core/src/events/dispatcher.rs

@@ -154,8 +154,8 @@ impl Dispatcher {
 
     let nearest_focus = self.pointer_down_uid.and_then(|wid| {
       wid.ancestors(tree).find(|id| {
-        id.query_ref::<MixBuiltin>(tree)
-          .map_or(false, |m| m.contain_flag(MixFlags::Focus))
+        id.query_all_iter::<MixBuiltin>(tree)
+          .any(|m| m.contain_flag(MixFlags::Focus))
       })
     });
     if let Some(focus_id) = nearest_focus {

core/src/events/focus_mgr.rs

@@ -361,8 +361,8 @@ impl FocusManager {
       .filter(|wid| !wid.is_dropped(tree))
       .and_then(|wid| {
         wid
-          .query_ref::<MixBuiltin>(tree)
-          .map(|m| m.mix_flags().read().tab_index())
+          .query_all_iter::<MixBuiltin>(tree)
+          .find_map(|m| m.mix_flags().read().tab_index())
       })
       .unwrap_or_default()
   }

core/src/overlay.rs

@@ -124,7 +124,7 @@ impl Overlay {
   ///       overlay.show_map(move |w| {
   ///         let wid = wid.clone();
   ///         fn_widget! {
-  ///           let mut w = @$w {};
+  ///           let mut w = FatObj::new(w);
   ///           w.left_align_to(&wid, 0., ctx!());
   ///           w
   ///         }.into_widget()
@@ -157,10 +157,9 @@ impl Overlay {
     }
     self.show_map(
       move |w| {
-        fn_widget! {
-          @$w { anchor: Anchor::from_point(pos) }
-        }
-        .into_widget()
+        FatObj::new(w)
+          .anchor(Anchor::from_point(pos))
+          .into_widget()
       },
       wnd,
     );

core/src/pipe.rs

@@ -1548,12 +1548,12 @@ mod tests {
     wnd.draw_frame();
     wnd.assert_root_size(Size::new(0., 0.));
 
-    println!("Inner pipe update:");
+    // Inner pipe update
     *w_inner.write() += 1;
     wnd.draw_frame();
     wnd.assert_root_size(Size::new(0., 1.));
 
-    println!("Outter pipe update:");
+    // Outer pipe update
     *w_outer.write() += 1;
     wnd.draw_frame();
     wnd.assert_root_size(Size::new(1., 1.));
@@ -1731,7 +1731,7 @@ mod tests {
         pipe!($m_watcher;).map(move |_| {
           // margin is static, but its child MockBox is a pipe.
           let p = pipe!($son_watcher;).map(|_| MockBox { size: Size::zero() });
-          @$p { margin: EdgeInsets::all(1.) }
+          FatObj::new(p).margin(EdgeInsets::all(1.))
         })
       };
       @ $p {