Bevy version
main branch (71bf07f)
Operating system & version
OS: Windows 10
Rust toolchain: stable-x86_64-pc-windows-gnu 1.52.1
What you did
Despawning an entity with a GLTF scene child one update after its creation leads to a panic.
Here is minimal code reproducing the issue.
use bevy::{
prelude::*,
};
#[derive(Default)]
struct State {
entity: Option<Entity>,
delay: usize,
}
fn update(
mut commands: Commands,
assets: Res<AssetServer>,
mut state: Local<State>,
) {
if let Some(id) = state.entity {
if state.delay == 0 {
commands.entity(id).despawn_recursive();
state.entity = None;
} else {
state.delay -= 1;
}
} else {
let id = commands
.spawn()
.with_children(|parent| {
let handle: Handle<Scene> = assets.load("alien.glb#Scene0"); // no panic with "alien.glb"
parent.spawn_scene(handle);
}).id();
state.entity = Some(id);
state.delay = 0; // no panic when set to 1
}
}
fn main() {
App::build()
.add_plugins(DefaultPlugins)
.add_system(update.system())
.run();
}What you expected to happen
Entity is despawned, no panic.
Sample program above will spawn/despawn entities indefinitely.
What actually happened
After the first despawn, program panics with an Entity does not exist error and the following backtrace (truncated):
thread 'main' panicked at 'Entity does not exist', C:\Users\user\bevy\crates\bevy_ecs\src\world\mod.rs:215:37
stack backtrace:
0: rust_begin_unwind
at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53\/library\std\src/panicking.rs:493:5
1: core::panicking::panic_fmt
at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53\/library\core\src/panicking.rs:92:14
2: core::option::expect_failed
at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53\/library\core\src/option.rs:1321:5
3: core::option::Option<T>::expect
at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53\library\core\src/option.rs:349:21
4: bevy_ecs::world::World::entity_mut
at C:\Users\user\bevy\crates\bevy_transform/C:\Users\user\bevy\crates\bevy_ecs\src\world/mod.rs:215:9
5: <bevy_ecs::system::commands::Insert<T> as bevy_ecs::system::commands::Command>::write
at C:\Users\user\bevy\crates\bevy_transform/C:\Users\user\bevy\crates\bevy_ecs\src\system/commands.rs:356:9
6: bevy_ecs::system::commands::CommandQueue::apply
at C:\Users\user\bevy\crates\bevy_ecs/C:\Users\user\bevy\crates\bevy_ecs\src\system/commands.rs:27:13
7: <bevy_ecs::system::commands::CommandQueue as bevy_ecs::system::system_param::SystemParamState>::apply
at C:\Users\user\bevy\crates\bevy_ecs/C:\Users\user\bevy\crates\bevy_ecs\src\system/system_param.rs:489:9
8: <(P0,P1,P2,P3) as bevy_ecs::system::system_param::SystemParamState>::apply
at C:\Users\user\bevy\crates\bevy_transform/C:\Users\user\bevy\crates\bevy_ecs\src\system/system_param.rs:1107:19
9: <bevy_ecs::system::function_system::FunctionSystem<In,Out,Param,Marker,F> as bevy_ecs::system::system::System>::apply_buffers
at C:\Users\user\bevy\crates\bevy_transform/C:\Users\user\bevy\crates\bevy_ecs\src\system/function_system.rs:338:9
10: <bevy_ecs::schedule::stage::SystemStage as bevy_ecs::schedule::stage::Stage>::run
at C:\Users\user\bevy\crates\bevy_ecs/C:\Users\user\bevy\crates\bevy_ecs\src\schedule/stage.rs:830:25
11: bevy_ecs::schedule::Schedule::run_once
at C:\Users\user\bevy\crates\bevy_ecs/C:\Users\user\bevy\crates\bevy_ecs\src\schedule/mod.rs:208:13
12: <bevy_ecs::schedule::Schedule as bevy_ecs::schedule::stage::Stage>::run
at C:\Users\user\bevy\crates\bevy_ecs/C:\Users\user\bevy\crates\bevy_ecs\src\schedule/mod.rs:226:21
13: bevy_app::app::App::update
at C:\Users\user\bevy\crates\bevy_app/C:\Users\user\bevy\crates\bevy_app\src/app.rs:62:9
<snipped>
Additional information
alien.glb is from bevy's assets, but I reproduced with other .glb files- It does not panic when using
alien.glb asset path instead of alien.glb#Scene0.
- It does not panic when delaying the
despawn_recursive() to the next system call (initialize state.delay to 1 after spawn in sample code).
- I'm not familiar with entity parenting, nor if it could be a known limitation of GLTF scenes. May I have misused something?
Bevy version
main branch (71bf07f)
Operating system & version
OS: Windows 10
Rust toolchain: stable-x86_64-pc-windows-gnu 1.52.1
What you did
Despawning an entity with a GLTF scene child one update after its creation leads to a panic.
Here is minimal code reproducing the issue.
What you expected to happen
Entity is despawned, no panic.
Sample program above will spawn/despawn entities indefinitely.
What actually happened
After the first despawn, program panics with an
Entity does not existerror and the following backtrace (truncated):Additional information
alien.glbis from bevy's assets, but I reproduced with other .glb filesalien.glbasset path instead ofalien.glb#Scene0.despawn_recursive()to the next system call (initializestate.delayto 1 after spawn in sample code).