How can I query for newly created entities created in the same schedule?

[mad-coder-365]

I am adding systems

fn build(&self, app: &mut App) {
        app
            .add_systems(
                PostStartup,
                (spawn_tiles_parent, setup_tiles).chain(),
            )
 }
 
 #[derive(Component)]
 struct TileParent;
    
fn spawn_tiles_parent(mut commands: Commands) {
    commands.spawn((SpatialBundle::default(), TileParent, Name::new("Tiles")));
}

fn setup_tiles(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    parent: Query<Entity, With<TileParent>>,
) {
        let parent_entity: Entity = parent.single();
        ...
}

I am getting an error:

INFO bevy_winit::system: Creating new window "App" (0v0)
thread 'Compute Task Pool (1)' panicked at src/tile.rs:60:44:
called `Result::unwrap()` on an `Err` value: NoEntities("bevy_ecs::query::state::QueryState<bevy_ecs::entity::Entity, bevy_ecs::query::filter::With<bevy_test::tile::TileParent>>")
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Encountered a panic in system `bevy_test::tile::setup_tiles`!
Encountered a panic in system `bevy_app::main_schedule::Main::run_main`!
thread '<unnamed>' panicked at /bevy_ecs-0.11.3/src/storage/resource.rs:56:13:
Attempted to access or drop non-send resource bevy_render::view::window::NonSendMarker from thread Some(ThreadId(1)) on a thread ThreadId(14). This is not allowed. Aborting.

Systems are being added in order: spawn_tiles_parent, setup_tiles

I am even tried adding like setup_tiles.after(spawn_tiles_parent) and still get the error.

How can I query for newly created entities created in the same schedule?

[rlidwka]

Use this:

app.add_systems(PostStartup, (
    spawn_tiles_parent,
    apply_deferred, // flush command buffers
    setup_tiles,
).chain())

Any commands you add are not executed immediately, they are only applied at the next stage. You can add apply_deferred to do so manually whenever you need it.

[mad-coder-365]

Thanks. It worked!