Function moonshine_check::purge

pub fn purge() -> Policy

Returns a Policy which despawns matching instances and all of their children.

Usage

Use this policy to remove invalid entities from the world.

Example

use bevy::prelude::*;
use moonshine_check::prelude::*;

#[derive(Bundle, Default)]
struct AB {
    a: A,
    b: B,
}

#[derive(Component, Default)]
struct A;

#[derive(Component, Default)]
struct B;

let mut app = App::new();
app.add_plugins(MinimalPlugins)
    .check::<A, Without<B>>(purge())
    .add_systems(Update, update);

app.world_mut().spawn(AB::default()); // OK!
app.world_mut().spawn(A); // Bug! `B` is missing!
app.update();

fn update(items: Query<Entity, With<A>>, query: Query<&B>) {
    for entity in items.iter() {
        // Guaranteed:
        assert!(query.contains(entity));
    }
}