`dispatch_focused_input` not checking whether the focused entity is alive or not.

[notmd]

Bevy version

main

What you did

Run the following code and try to press some key.

use bevy::{
    ecs::entity::Entities,
    input::keyboard::KeyboardInput,
    input_focus::{FocusedInput, InputDispatchPlugin, InputFocus, set_initial_focus},
    prelude::*,
};

fn main() {
    App::new()
        .add_plugins((DefaultPlugins, InputDispatchPlugin))
        .add_systems(PostStartup, setup.after(set_initial_focus))
        .add_observer(on_keyboard_input)
        .run();
}

fn setup(mut input_focus: ResMut<InputFocus>, mut commands: Commands) {
    let entity = commands.spawn_empty().id();
    input_focus.0 = Some(entity);
    commands.entity(entity).despawn();
}

fn on_keyboard_input(trigger: Trigger<FocusedInput<KeyboardInput>>, entities: &Entities) {
    assert!(entities.contains(trigger.target()));
}

What went wrong

It's should not crash. Bevy should check the entity is alive or not. If not the event should be triggered on window entity.

Additional information

None.