Removing any elements from KayakApp causes a panic

[bayou-brogrammer]

Using the hello_world as an example, if I have the following setup:

fn startup(
    mut commands: Commands,
    mut font_mapping: ResMut<FontMapping>,
    asset_server: Res<AssetServer>,
) {
    font_mapping.set_default(asset_server.load("roboto.kayak_font"));

    let mut widget_context = KayakRootContext::new();
    widget_context.add_plugin(KayakWidgetsContextPlugin);
    let parent_id = None;
    rsx! {
        <KayakAppBundle>
            <TextWidgetBundle
                text={TextProps {
                    content: "Hello World".into(),
                    size: 20.0,
                    ..Default::default()
                }}
            />
        </KayakAppBundle>
    }

    commands.spawn(UICameraBundle::new(widget_context));
}

fn remove_child(
    mut commands: Commands,
    keys: Res<Input<KeyCode>>,
    q: Query<Entity, With<TextProps>>,
) {
    if keys.just_pressed(KeyCode::Space) {
        q.iter().for_each(|e| {
            commands.entity(e).despawn_recursive();
        });
    }
}

And if I say remove the TextWidgetBundle from the KayakApp, it causes a panic. This goes for anything under the RootContext, if i try to remove KayakApp it panics as well

[StarArawn]

What is happening is that the entities are despawned but they still exist in the tree(which lives in context). I think we need a way of resetting the context. Still a question arises from this, what should happen when a widget entity is despawned? Should it be auto removed from the tree? Should we ignore and error or warn in the console?

[bayou-brogrammer]

NMy first pass thought would be to treat it as a react virtual DOM would where removing an element from the dom, alienates it from the context and allows it to be flushed.

I think there should be a warning of an element inside of the tree is attempted to access, but doesn't exist. But this would require a method or methods ontop of the context that allows for removing entities.

Definitely a tricky situation since the easiest solution in bevy is to remove entities recursively like I have shown, but that won't pull them from the context.

EDIT: a first pass I would say remove entities from the tree if they no longer exist within bevy. A second pass might allow for a better use case where we can flush a context and rebuild it forcing any entities not alive to be removed

[StarArawn]

@lecoqjacob Is this still an issue? I'm pretty sure I made some changes which should help with this.