Port example 04

lib/ruin_app/Cargo.toml

@@ -29,3 +29,7 @@ path = "example/02_widget_refs_and_commands.rs"
 [[example]]
 name = "03_fine_grained_list"
 path = "example/03_fine_grained_list.rs"
+
+[[example]]
+name = "04_composition_and_context"
+path = "example/04_composition_and_context.rs"

lib/ruin_app/example/04_composition_and_context.rs

@@ -0,0 +1,340 @@
+use ruin_app::prelude::*;
+
+#[ruin_runtime::async_main]
+async fn main() -> ruin_app::Result<()> {
+    App::new()
+        .window(
+            Window::new()
+                .title("RUIN Workspace")
+                .app_id("dev.ruin.composition-context")
+                .size(1280.0, 840.0),
+        )
+        .mount(view! {
+            WorkspaceRoot() {}
+        })
+        .run()
+        .await
+}
+
+#[component]
+fn WorkspaceRoot() -> impl IntoView {
+    let notifications = Notifications::new(use_signal(|| {
+        "No workspace actions yet. Click a navigation button to emit a context-driven update."
+            .to_string()
+    }));
+    let session = SessionInfo::guest();
+
+    view! {
+        provide::<NotificationsContext>(value = notifications.clone()) {
+            provide::<SessionContext>(value = session.clone()) {
+                provide::<AppThemeContext>(value = ThemePalette::workspace()) {
+                    WorkspaceShell() {}
+                }
+            }
+        }
+    }
+}
+
+#[component]
+fn WorkspaceShell() -> impl IntoView {
+    let session = use_context::<SessionContext>();
+    let notifications = use_context::<NotificationsContext>();
+    let theme = use_context::<AppThemeContext>();
+
+    use_window_title({
+        let session = session.clone();
+        move || format!("RUIN Workspace - {}", session.workspace)
+    });
+
+    view! {
+        column(gap = 16.0, padding = 20.0, background = theme.canvas) {
+            block(
+                padding = 14.0,
+                gap = 8.0,
+                background = theme.panel,
+                border_radius = 12.0,
+                border = (1.0, theme.accent),
+            ) {
+                text(role = TextRole::Heading(1), size = 30.0, weight = FontWeight::Semibold) {
+                    "Composition and typed context"
+                }
+                text(color = theme.muted, wrap = TextWrap::Word) {
+                    "This example implements real marker-keyed context providers. `AppThemeContext` \
+                     and `SidebarThemeContext` both carry the same `ThemePalette` value type, but \
+                     descendants resolve them independently by marker type. Nested providers of the \
+                     same marker also shadow outer values as you would expect."
+                }
+                text(color = theme.muted) {
+                    "Last notification: ";
+                    notifications.last_message.clone()
+                }
+            }
+
+            row(gap = 16.0) {
+                provide::<SidebarThemeContext>(value = ThemePalette::sidebar()) {
+                    Sidebar() {}
+                }
+
+                Dashboard() {}
+            }
+        }
+    }
+}
+
+#[component]
+fn Sidebar() -> impl IntoView {
+    let theme = use_context::<SidebarThemeContext>();
+    let session = use_context::<SessionContext>();
+    let notifications = use_context::<NotificationsContext>();
+
+    view! {
+        block(
+            width = 300.0,
+            padding = 16.0,
+            gap = 12.0,
+            background = theme.panel,
+            border_radius = 14.0,
+            border = (1.0, theme.accent),
+        ) {
+            text(size = 24.0, weight = FontWeight::Semibold, color = theme.text) {
+                "Workspace nav"
+            }
+
+            text(color = theme.muted, wrap = TextWrap::Word) {
+                "Signed in as ";
+                session.user.clone();
+                " in ";
+                session.workspace.clone();
+            }
+
+            button(on_press = {
+                let notifications = notifications.clone();
+                move |_| notifications.info("Opened the Home workspace panel")
+            }) { "Home" }
+
+            button(on_press = {
+                let notifications = notifications.clone();
+                move |_| notifications.info("Opened the Projects workspace panel")
+            }) { "Projects" }
+
+            button(on_press = {
+                let notifications = notifications.clone();
+                move |_| notifications.info("Opened the Settings workspace panel")
+            }) { "Settings" }
+
+            block(
+                padding = 12.0,
+                gap = 8.0,
+                background = theme.canvas,
+                border_radius = 10.0,
+            ) {
+                text(weight = FontWeight::Semibold, color = theme.accent) { "Sidebar theme" }
+                text(color = theme.muted, wrap = TextWrap::Word) {
+                    "This panel resolves `SidebarThemeContext`, even though the rest of the \
+                     workspace uses `AppThemeContext` with the same `ThemePalette` value type."
+                }
+            }
+        }
+    }
+}
+
+#[component]
+fn Dashboard() -> impl IntoView {
+    let theme = use_context::<AppThemeContext>();
+    let session = use_context::<SessionContext>();
+
+    view! {
+        column(flex = 1.0, gap = 16.0) {
+            block(
+                padding = 16.0,
+                gap = 10.0,
+                background = theme.panel,
+                border_radius = 14.0,
+                border = (1.0, theme.accent),
+            ) {
+                text(size = 24.0, weight = FontWeight::Semibold, color = theme.text) {
+                    "Workspace dashboard"
+                }
+                text(color = theme.muted, wrap = TextWrap::Word) {
+                    "The main content resolves `AppThemeContext` and `SessionContext` from the \
+                     outer providers. These values are regular cloned Rust values; the context \
+                     system is responsible only for scoping and lookup by marker type."
+                }
+                text(color = theme.muted) {
+                    "Active workspace: ";
+                    session.workspace.clone()
+                }
+            }
+
+            column(gap = 16.0) {
+                ThemeCard(
+                    title = "App theme".to_string(),
+                    subtitle = "Resolved from the outer `AppThemeContext` provider.".to_string(),
+                    theme = theme.clone(),
+                ) {}
+
+                provide::<AppThemeContext>(value = ThemePalette::inspector()) {
+                    InspectorPanel() {}
+                }
+            }
+        }
+    }
+}
+
+#[component]
+fn ThemeCard(title: String, subtitle: String, theme: ThemePalette) -> impl IntoView {
+    view! {
+        block(
+            padding = 16.0,
+            gap = 10.0,
+            background = theme.panel,
+            border_radius = 14.0,
+            border = (1.0, theme.accent),
+        ) {
+            text(size = 20.0, weight = FontWeight::Semibold, color = theme.text) { title }
+            text(color = theme.muted, wrap = TextWrap::Word) { subtitle }
+            block(
+                height = 56.0,
+                background = theme.canvas,
+                border_radius = 10.0,
+                border = (2.0, theme.accent),
+            ) {}
+        }
+    }
+}
+
+#[component]
+fn InspectorPanel() -> impl IntoView {
+    let theme = use_context::<AppThemeContext>();
+    let notifications = use_context::<NotificationsContext>();
+
+    view! {
+        block(
+            padding = 16.0,
+            gap = 12.0,
+            background = theme.canvas,
+            border_radius = 14.0,
+            border = (1.0, theme.accent),
+        ) {
+            text(size = 18.0, weight = FontWeight::Semibold, color = theme.accent) {
+                "Inspector panel"
+            }
+
+            ThemeCard(
+                title = "Nested override".to_string(),
+                subtitle = "This panel shadows the outer `AppThemeContext` with a nearer provider of the same marker type.".to_string(),
+                theme = theme.clone(),
+            ) {}
+
+            button(on_press = {
+                let notifications = notifications.clone();
+                move |_| notifications.info("Inspector theme override is active")
+            }) { "Emit inspector notification" }
+        }
+    }
+}
+
+#[context_provider(ThemePalette)]
+struct AppThemeContext;
+
+#[context_provider(ThemePalette)]
+struct SidebarThemeContext;
+
+#[context_provider(SessionInfo)]
+struct SessionContext;
+
+#[context_provider(Notifications)]
+struct NotificationsContext;
+
+#[derive(Clone)]
+struct ThemePalette {
+    canvas: Color,
+    panel: Color,
+    accent: Color,
+    text: Color,
+    muted: Color,
+}
+
+impl ThemePalette {
+    fn workspace() -> Self {
+        Self {
+            canvas: Color::rgb(0x0E, 0x14, 0x20),
+            panel: Color::rgb(0x16, 0x1F, 0x30),
+            accent: Color::rgb(0x71, 0xA7, 0xF7),
+            text: Color::rgb(0xF5, 0xF7, 0xFB),
+            muted: Color::rgb(0x9A, 0xA9, 0xC2),
+        }
+    }
+
+    fn sidebar() -> Self {
+        Self {
+            canvas: Color::rgb(0x0F, 0x17, 0x24),
+            panel: Color::rgb(0x1A, 0x24, 0x36),
+            accent: Color::rgb(0x8B, 0xC3, 0x7E),
+            text: Color::rgb(0xF3, 0xF7, 0xEF),
+            muted: Color::rgb(0xA7, 0xB5, 0xA4),
+        }
+    }
+
+    fn inspector() -> Self {
+        Self {
+            canvas: Color::rgb(0x22, 0x17, 0x0F),
+            panel: Color::rgb(0x35, 0x24, 0x16),
+            accent: Color::rgb(0xF4, 0xB7, 0x56),
+            text: Color::rgb(0xFC, 0xF6, 0xEB),
+            muted: Color::rgb(0xCF, 0xB8, 0x98),
+        }
+    }
+}
+
+#[derive(Clone)]
+struct SessionInfo {
+    user: String,
+    workspace: String,
+}
+
+impl SessionInfo {
+    fn guest() -> Self {
+        Self {
+            user: "guest".to_string(),
+            workspace: "ruin".to_string(),
+        }
+    }
+}
+
+#[derive(Clone)]
+struct Notifications {
+    last_message: Signal<String>,
+}
+
+impl Notifications {
+    fn new(last_message: Signal<String>) -> Self {
+        Self { last_message }
+    }
+
+    fn info(&self, message: impl Into<String>) {
+        self.last_message.replace(message.into());
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn inspector_panel_text_reaches_the_scene() {
+        let root = WorkspaceRoot::builder().children(());
+        let view = ruin_app::__render_mountable_for_test(&root);
+        let snapshot = ruin_ui::layout_snapshot(1, UiSize::new(1280.0, 840.0), view.element());
+
+        assert!(
+            snapshot.scene.items.iter().any(|item| matches!(
+                item,
+                ruin_ui::DisplayItem::Text(text)
+                    if text.text.contains("Nested override")
+                        || text.text.contains("Inspector panel")
+            )),
+            "expected InspectorPanel text to appear in the rendered scene",
+        );
+    }
+}

lib/ruin_app/src/lib.rs

@@ -3,7 +3,7 @@
 //! This crate is intentionally low-level. It is the substrate that a future proc-macro-driven
 //! component system can expand to, not the final ergonomic authoring API.
 
-use std::any::Any;
+use std::any::{Any, TypeId, type_name};
 use std::cell::{Cell as StdCell, RefCell};
 use std::collections::HashMap;
 use std::error::Error;
@@ -25,7 +25,7 @@ use ruin_ui::{
 use ruin_ui_platform_wayland::start_wayland_ui;
 
 pub use ResourceState::{Pending, Ready};
-pub use ruin_app_proc_macros::{component, view};
+pub use ruin_app_proc_macros::{component, context_provider, view};
 
 pub type Result<T> = std::result::Result<T, Box<dyn Error>>;
 
@@ -94,6 +94,11 @@ impl Default for App {
     }
 }
 
+#[doc(hidden)]
+pub fn __render_mountable_for_test<M: Mountable>(mountable: &M) -> View {
+    render_with_context(Rc::new(RenderState::default()), || mountable.render()).view
+}
+
 pub trait Mountable: 'static {
     fn render(&self) -> View;
 }
@@ -105,6 +110,10 @@ pub trait Component: 'static {
     fn render(&self) -> View;
 }
 
+pub trait ContextKey: 'static {
+    type Value: Clone + 'static;
+}
+
 impl<T: Component> Mountable for T {
     fn render(&self) -> View {
         Component::render(self)
@@ -1147,10 +1156,57 @@ impl<T: Clone> Memo<T> {
     }
 }
 
+#[derive(Clone)]
+struct ContextEntry {
+    key: TypeId,
+    value: Rc<dyn Any>,
+}
+
+impl ContextEntry {
+    fn new<C: ContextKey>(value: C::Value) -> Self {
+        Self {
+            key: TypeId::of::<C>(),
+            value: Rc::new(value),
+        }
+    }
+}
+
 pub fn use_signal<T: 'static>(initial: impl FnOnce() -> T) -> Signal<T> {
     with_hook_slot(|| Signal::new(initial()), |signal| signal.clone())
 }
 
+pub fn use_context<C: ContextKey>() -> C::Value {
+    with_render_context_state(|context| {
+        context
+            .context_entries
+            .iter()
+            .rev()
+            .find_map(|entry| {
+                (entry.key == TypeId::of::<C>())
+                    .then(|| entry.value.downcast_ref::<C::Value>())
+                    .flatten()
+                    .cloned()
+            })
+            .unwrap_or_else(|| {
+                panic!(
+                    "missing context provider for {} while rendering",
+                    type_name::<C>()
+                )
+            })
+    })
+}
+
+pub fn provide<C: ContextKey>(value: C::Value, render: impl FnOnce() -> View) -> View {
+    with_render_context_state(|context| {
+        let mut context_entries = (*context.context_entries).clone();
+        context_entries.push(ContextEntry::new::<C>(value));
+        with_render_context(
+            context.with_context_entries(Rc::new(context_entries)),
+            render,
+        )
+    })
+}
+
 pub fn use_memo<T: 'static>(compute: impl Fn() -> T + 'static) -> Memo<T> {
     let compute: Rc<RefCell<Box<dyn Fn() -> T>>> =
         Rc::new(RefCell::new(Box::new(compute) as Box<dyn Fn() -> T>));
@@ -1434,6 +1490,19 @@ struct RenderContext {
     hook_index: Rc<StdCell<usize>>,
     element_index: Rc<StdCell<usize>>,
     side_effects: Rc<RefCell<RenderSideEffects>>,
+    context_entries: Rc<Vec<ContextEntry>>,
+}
+
+impl RenderContext {
+    fn with_context_entries(&self, context_entries: Rc<Vec<ContextEntry>>) -> Self {
+        Self {
+            state: Rc::clone(&self.state),
+            hook_index: Rc::clone(&self.hook_index),
+            element_index: Rc::clone(&self.element_index),
+            side_effects: Rc::clone(&self.side_effects),
+            context_entries,
+        }
+    }
 }
 
 struct RenderOutput {
@@ -1451,8 +1520,15 @@ fn render_with_context(state: Rc<RenderState>, render: impl FnOnce() -> View) ->
         hook_index: Rc::new(StdCell::new(0)),
         element_index: Rc::new(StdCell::new(0)),
         side_effects: Rc::new(RefCell::new(RenderSideEffects::default())),
+        context_entries: Rc::new(Vec::new()),
     };
 
+    let view = with_render_context(context.clone(), render);
+    let side_effects = context.side_effects.borrow().clone();
+    RenderOutput { view, side_effects }
+}
+
+fn with_render_context(context: RenderContext, render: impl FnOnce() -> View) -> View {
     CURRENT_RENDER_CONTEXT.with(|slot| {
         let previous = slot.replace(Some(context.clone()));
 
@@ -1468,19 +1544,17 @@ fn render_with_context(state: Rc<RenderState>, render: impl FnOnce() -> View) ->
         }
 
         let _guard = Guard { slot, previous };
-        let view = render();
-        let side_effects = context.side_effects.borrow().clone();
-        RenderOutput { view, side_effects }
+        render()
     })
 }
 
 fn with_render_context_state<R>(f: impl FnOnce(&RenderContext) -> R) -> R {
     CURRENT_RENDER_CONTEXT.with(|slot| {
-        let context = slot.borrow();
-        let context = context
-            .as_ref()
+        let context = slot
+            .borrow()
+            .clone()
             .expect("ruin_app hooks can only run while rendering a mounted component");
-        f(context)
+        f(&context)
     })
 }
 
@@ -1837,13 +1911,13 @@ fn build_focused_ancestor_chain(
 
 pub mod prelude {
     pub use crate::{
-        App, BlockWidget, ButtonBuilder, Children, Component, ContainerBuilder, FocusScope,
-        FontWeight, IntoBorder, IntoEdges, IntoView, Key, Memo, Mountable, Pending, Ready,
-        Resource, ResourceState, Result, ScrollBoxBuilder, ScrollBoxWidget, Shortcut,
+        App, BlockWidget, ButtonBuilder, Children, Component, ContainerBuilder, ContextKey,
+        FocusScope, FontWeight, IntoBorder, IntoEdges, IntoView, Key, Memo, Mountable, Pending,
+        Ready, Resource, ResourceState, Result, ScrollBoxBuilder, ScrollBoxWidget, Shortcut,
         ShortcutScope, Signal, TextBuilder, TextChildren, TextRole, View, WidgetRef, Window, block,
-        button, colors, column, component, row, scroll_box, surfaces, text, use_effect, use_memo,
-        use_resource, use_shortcut, use_shortcut_with_context, use_signal, use_widget_ref,
-        use_window_title, view,
+        button, colors, column, component, context_provider, provide, row, scroll_box, surfaces,
+        text, use_context, use_effect, use_memo, use_resource, use_shortcut,
+        use_shortcut_with_context, use_signal, use_widget_ref, use_window_title, view,
     };
     pub use ruin_ui::{
         Border, Color, CursorIcon, Edges, Element, ElementId, InteractionTree, PointerButton,
@@ -1851,6 +1925,68 @@ pub mod prelude {
         TextFontFamily, TextStyle, TextWrap, UiSize,
     };
 }
+
 struct SignalInner<T> {
     cell: ruin_reactivity::Cell<T>,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[derive(Clone, Debug, PartialEq, Eq)]
+    struct NamedValue(&'static str);
+
+    struct OuterContext;
+    struct InnerContext;
+
+    impl ContextKey for OuterContext {
+        type Value = NamedValue;
+    }
+
+    impl ContextKey for InnerContext {
+        type Value = NamedValue;
+    }
+
+    #[test]
+    fn use_context_distinguishes_marker_types_for_same_value_type() {
+        let seen_outer = Rc::new(RefCell::new(None::<NamedValue>));
+        let seen_inner = Rc::new(RefCell::new(None::<NamedValue>));
+
+        let _ = render_with_context(Rc::new(RenderState::default()), {
+            let seen_outer = Rc::clone(&seen_outer);
+            let seen_inner = Rc::clone(&seen_inner);
+            move || {
+                provide::<OuterContext>(NamedValue("outer"), || {
+                    provide::<InnerContext>(NamedValue("inner"), || {
+                        *seen_outer.borrow_mut() = Some(use_context::<OuterContext>());
+                        *seen_inner.borrow_mut() = Some(use_context::<InnerContext>());
+                        View::from_element(Element::column())
+                    })
+                })
+            }
+        });
+
+        assert_eq!(*seen_outer.borrow(), Some(NamedValue("outer")));
+        assert_eq!(*seen_inner.borrow(), Some(NamedValue("inner")));
+    }
+
+    #[test]
+    fn nearer_provider_shadows_outer_provider_of_same_marker() {
+        let seen_value = Rc::new(RefCell::new(None::<NamedValue>));
+
+        let _ = render_with_context(Rc::new(RenderState::default()), {
+            let seen_value = Rc::clone(&seen_value);
+            move || {
+                provide::<OuterContext>(NamedValue("outer"), || {
+                    provide::<OuterContext>(NamedValue("inner"), || {
+                        *seen_value.borrow_mut() = Some(use_context::<OuterContext>());
+                        View::from_element(Element::column())
+                    })
+                })
+            }
+        });
+
+        assert_eq!(*seen_value.borrow(), Some(NamedValue("inner")));
+    }
+}

lib/ruin_app_proc_macros/src/lib.rs

@@ -4,8 +4,8 @@ use quote::{format_ident, quote};
 use syn::parse::{Parse, ParseStream};
 use syn::punctuated::Punctuated;
 use syn::{
-    Error, Expr, FnArg, Ident, ItemFn, Pat, PatIdent, Path, Result, ReturnType, Token, Type,
-    braced, parenthesized, parse_macro_input,
+    Error, Expr, FnArg, Ident, ItemFn, ItemStruct, Pat, PatIdent, Path, Result, ReturnType, Token,
+    Type, braced, parenthesized, parse_macro_input,
 };
 
 #[proc_macro_attribute]
@@ -29,6 +29,16 @@ pub fn view(input: TokenStream) -> TokenStream {
     expand_node(&root.root).into()
 }
 
+#[proc_macro_attribute]
+pub fn context_provider(attr: TokenStream, item: TokenStream) -> TokenStream {
+    let value_ty = parse_macro_input!(attr as Type);
+    let item_struct = parse_macro_input!(item as ItemStruct);
+    match expand_context_provider(item_struct, value_ty) {
+        Ok(tokens) => tokens.into(),
+        Err(error) => error.to_compile_error().into(),
+    }
+}
+
 fn expand_component(mut function: ItemFn) -> Result<proc_macro2::TokenStream> {
     validate_component_function(&function)?;
 
@@ -256,6 +266,34 @@ fn expand_component(mut function: ItemFn) -> Result<proc_macro2::TokenStream> {
     })
 }
 
+fn expand_context_provider(
+    item_struct: ItemStruct,
+    value_ty: Type,
+) -> Result<proc_macro2::TokenStream> {
+    if !item_struct.generics.params.is_empty() || item_struct.generics.where_clause.is_some() {
+        return Err(Error::new_spanned(
+            &item_struct.generics,
+            "context providers cannot be generic",
+        ));
+    }
+    if !matches!(item_struct.fields, syn::Fields::Unit) {
+        return Err(Error::new_spanned(
+            &item_struct.fields,
+            "context providers must be unit structs",
+        ));
+    }
+
+    let ident = &item_struct.ident;
+
+    Ok(quote! {
+        #item_struct
+
+        impl ::ruin_app::ContextKey for #ident {
+            type Value = #value_ty;
+        }
+    })
+}
+
 fn validate_component_function(function: &ItemFn) -> Result<()> {
     let signature = &function.sig;
 
@@ -443,6 +481,9 @@ fn looks_like_node(input: ParseStream<'_>) -> Result<bool> {
 
 fn expand_node(node: &Node) -> proc_macro2::TokenStream {
     let path = &node.path;
+    if is_provider_path(path) {
+        return expand_provider_node(node);
+    }
     let prop_calls = node.props.iter().map(|property| {
         let name = &property.name;
         let value = &property.value;
@@ -465,6 +506,34 @@ fn expand_node(node: &Node) -> proc_macro2::TokenStream {
     }
 }
 
+fn expand_provider_node(node: &Node) -> proc_macro2::TokenStream {
+    let path = &node.path;
+    let value = match node.props.as_slice() {
+        [Property { name, value }] if name == "value" => value,
+        _ => {
+            return Error::new_spanned(
+                path,
+                "provide::<Context>(...) expects exactly one `value = ...` property",
+            )
+            .to_compile_error();
+        }
+    };
+    let child = match node.children.as_slice() {
+        [child] => expand_child(child),
+        _ => {
+            return Error::new_spanned(path, "provide::<Context>(...) requires exactly one child")
+                .to_compile_error();
+        }
+    };
+
+    quote! {
+        ::ruin_app::#path(
+            #value,
+            || ::ruin_app::IntoView::into_view(#child),
+        )
+    }
+}
+
 fn expand_children(children: &[Child]) -> proc_macro2::TokenStream {
     match children {
         [] => quote! { () },
@@ -491,3 +560,12 @@ fn is_component_path(path: &Path) -> bool {
         .map(|ch| ch.is_ascii_uppercase())
         .unwrap_or(false)
 }
+
+fn is_provider_path(path: &Path) -> bool {
+    !is_component_path(path)
+        && path
+            .segments
+            .last()
+            .map(|segment| segment.ident == "provide")
+            .unwrap_or(false)
+}

lib/ui/src/layout.rs

@@ -383,11 +383,17 @@ fn layout_element(
     perf_stats.container_nodes += 1;
 
     if element.children.is_empty() {
+        if pushed_clip {
+            scene.pop_clip();
+        }
         return interaction;
     }
 
     let content = inset_rect(rect, content_insets(&element.style));
     if content.size.width <= 0.0 || content.size.height <= 0.0 {
+        if pushed_clip {
+            scene.pop_clip();
+        }
         return interaction;
     }
     interaction.children = layout_container_children(
@@ -1543,6 +1549,40 @@ mod tests {
         );
     }
 
+    #[test]
+    fn empty_rounded_container_pops_clip_before_following_sibling() {
+        let root = Element::column().children([
+            Element::column()
+                .height(56.0)
+                .corner_radius(12.0)
+                .background(Color::rgb(0x22, 0x33, 0x44)),
+            Element::paragraph(
+                "Sibling text should not inherit a stale clip from an empty rounded container.",
+                TextStyle::new(18.0, Color::rgb(0xFF, 0xFF, 0xFF)).with_line_height(24.0),
+            ),
+        ]);
+
+        let scene = layout_scene(1, UiSize::new(480.0, 240.0), &root);
+        let rounded_push = scene
+            .items
+            .iter()
+            .position(|item| matches!(item, DisplayItem::PushClip(_)))
+            .expect("rounded empty container should push a clip");
+        let rounded_pop = scene
+            .items
+            .iter()
+            .position(|item| matches!(item, DisplayItem::PopClip))
+            .expect("rounded empty container should pop its clip");
+        let sibling_text = scene
+            .items
+            .iter()
+            .position(|item| matches!(item, DisplayItem::Text(text) if text.text.contains("Sibling text")))
+            .expect("following sibling text should be emitted");
+
+        assert!(rounded_push < rounded_pop);
+        assert!(rounded_pop < sibling_text);
+    }
+
     #[test]
     fn shadowed_container_emits_shadow_rect_items() {
         let root = Element::column().child(