bevy "effectbundle"

effect.rs

use bevy::{
    ecs::{
        bundle::{BundleEffect, DynamicBundle},
        component::{
            ComponentId, Components, ComponentsRegistrator, RequiredComponents, StorageType,
        },
    },
    prelude::*,
    ptr::OwningPtr,
};

pub struct EffectBundleFn(Box<dyn FnOnce(&mut EntityWorldMut) + Sync + Send + 'static>);
impl EffectBundleFn {
    pub fn new<F: FnOnce(&mut EntityWorldMut) + Sync + Send + 'static>(f: F) -> Self {
        Self(Box::new(f))
    }
}

unsafe impl Bundle for EffectBundleFn {
    fn get_component_ids(components: &Components, ids: &mut impl FnMut(Option<ComponentId>)) {
        <() as Bundle>::get_component_ids(components, ids);
    }

    fn register_required_components(
        components: &mut ComponentsRegistrator,
        required_components: &mut RequiredComponents,
    ) {
        <() as Bundle>::register_required_components(components, required_components);
    }

    fn component_ids(components: &mut ComponentsRegistrator, ids: &mut impl FnMut(ComponentId)) {
        <() as Bundle>::component_ids(components, ids);
    }
}

impl DynamicBundle for EffectBundleFn {
    type Effect = Self;

    fn get_components(self, func: &mut impl FnMut(StorageType, OwningPtr<'_>)) -> Self::Effect {
        <() as DynamicBundle>::get_components((), func);
        self
    }
}

impl BundleEffect for EffectBundleFn {
    fn apply(self, entity: &mut EntityWorldMut) {
        (self.0)(entity)
    }
}

For the second question i have no idea but there is an open github discussion about bsn so maybe ask there or in the ui channel on discord

@sum-catnip I think you need to be careful with this because you report to the ECS system that the bundle contains no components

fn get_component_ids(components: &Components, ids: &mut impl FnMut(Option<ComponentId>)) {
    <() as Bundle>::get_component_ids(components, ids);
}

but then in your type erased example demonstrate how EffectBundleFn can be used to insert components, does this lead to undefined behavior? Or is the insertion of components in the BundleEffect completely separate from the logic of Bundle?