panic when removing boundary

[rezural]

Is there anything I am doing wrong with this:

Removing a boundary, causes a panic.

Reproduction is here: https://github.com/rezural/salva/tree/panic-heightfield-boundaries

I changed the example heightfield3: rezural@0b94f1e#diff-6e95f7a94394df65d066f26ea4ce4087aa8caf504133160fef8dea6c01a75642

can be run with :

RUST_BACKTRACE=1 cargo run --release --features=parallel --bin all_examples3 -- --pause --example 'Height field'

basically:

#[derive(Clone, Copy)]
struct BoundaryHandles {
    collider: ColliderHandle,
    boundary: BoundaryHandle,
    body: RigidBodyHandle,
}

fn remove_boundary(
    handles: BoundaryHandles,
    fluids_pipeline: &mut FluidsPipeline,
    bodies: &mut RigidBodySet,
    colliders: &mut ColliderSet,
) {
    fluids_pipeline
        .coupling
        .unregister_coupling(handles.collider);

    fluids_pipeline
        .liquid_world
        .remove_boundary(handles.boundary);

    // bodies.remove(bodies);
}

removing previous boundaries
thread 'main' panicked at 'No element at index', build/salva3d/../../src/object/contiguous_arena.rs:128:13
stack backtrace:
  0: rust_begin_unwind
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/std/src/panicking.rs:515:5
  1: core::panicking::panic_fmt
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/panicking.rs:92:14
  2: core::option::expect_failed
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/option.rs:1578:5
  3: core::option::Option<T>::expect
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/option.rs:685:21
  4: <generational_arena::Arena<T> as core::ops::index::IndexMut<generational_arena::Index>>::index_mut
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/generational-arena-0.2.8/src/lib.rs:1305:9
  5: salva3d::object::contiguous_arena::ContiguousArena<Idx,T>::remove
            at /home/rezural/data/code/fluidsim/dm-examples/vendor/salva/build/salva3d/../../src/object/contiguous_arena.rs:128:13
  6: salva3d::liquid_world::LiquidWorld::remove_boundary
            at /home/rezural/data/code/fluidsim/dm-examples/vendor/salva/build/salva3d/../../src/liquid_world.rs:174:9
  7: all_examples3::heightfield3::remove_boundary
            at ./heightfield3.rs:110:5
  8: all_examples3::heightfield3::init_world::{{closure}}
            at ./heightfield3.rs:61:17
  9: <alloc::boxed::Box<F,A> as core::ops::function::FnMut<Args>>::call_mut
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/alloc/src/boxed.rs:1579:9
 10: <salva3d::integrations::rapier::testbed_plugin::FluidsTestbedPlugin as rapier_testbed3d::plugin::TestbedPlugin>::run_callbacks
            at /home/rezural/data/code/fluidsim/dm-examples/vendor/salva/build/salva3d/../../src/integrations/rapier/testbed_plugin.rs:315:13
 11: rapier_testbed3d::testbed::update_testbed
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/rapier_testbed3d-0.10.0/src_testbed/testbed.rs:1164:17
 12: core::ops::function::Fn::call
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/ops/function.rs:70:5
 13: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &F>::call_mut
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/ops/function.rs:247:13
 14: <Func as bevy_ecs::system::into_system::SystemParamFunction<(),Out,(F0,F1,F2,F3,F4,F5,F6,F7,F8,F9,F10,F11),()>>::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/system/into_system.rs:207:21
 15: <bevy_ecs::system::into_system::FunctionSystem<In,Out,Param,Marker,F> as bevy_ecs::system::system::System>::run_unsafe
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/system/into_system.rs:147:19
 16: bevy_ecs::system::system::System::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/system/system.rs:48:18
 17: <bevy_ecs::schedule::executor::SingleThreadedExecutor as bevy_ecs::schedule::executor::ParallelSystemExecutor>::run_systems
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/schedule/executor.rs:34:17
 18: <bevy_ecs::schedule::stage::SystemStage as bevy_ecs::schedule::stage::Stage>::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/schedule/stage.rs:822:17
 19: bevy_ecs::schedule::Schedule::run_once
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/schedule/mod.rs:201:13
 20: <bevy_ecs::schedule::Schedule as bevy_ecs::schedule::stage::Stage>::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.5.0/src/schedule/mod.rs:219:21
 21: bevy_app::app::App::update
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_app-0.5.0/src/app.rs:58:9
 22: bevy_winit::winit_runner_with::{{closure}}
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_winit-0.5.0/src/lib.rs:485:17
 23: winit::platform_impl::platform::sticky_exit_callback
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.24.0/src/platform_impl/linux/mod.rs:736:5
 24: winit::platform_impl::platform::x11::EventLoop<T>::run_return
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.24.0/src/platform_impl/linux/x11/mod.rs:303:17
 25: winit::platform_impl::platform::x11::EventLoop<T>::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.24.0/src/platform_impl/linux/x11/mod.rs:398:9
 26: winit::platform_impl::platform::EventLoop<T>::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.24.0/src/platform_impl/linux/mod.rs:652:56
 27: winit::event_loop::EventLoop<T>::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.24.0/src/event_loop.rs:154:9
 28: bevy_winit::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_winit-0.5.0/src/lib.rs:171:5
 29: bevy_winit::winit_runner_with
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_winit-0.5.0/src/lib.rs:493:9
 30: bevy_winit::winit_runner
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_winit-0.5.0/src/lib.rs:211:5
 31: core::ops::function::Fn::call
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/ops/function.rs:70:5
 32: <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/alloc/src/boxed.rs:1586:9
 33: bevy_app::app::App::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_app-0.5.0/src/app.rs:68:9
 34: bevy_app::app_builder::AppBuilder::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_app-0.5.0/src/app_builder.rs:49:9
 35: rapier_testbed3d::testbed::TestbedApp::run
            at /home/rezural/.cargo/registry/src/github.com-1ecc6299db9ec823/rapier_testbed3d-0.10.0/src_testbed/testbed.rs:418:13
 36: all_examples3::main
            at ./all_examples3.rs:76:5
 37: core::ops::function::FnOnce::call_once
            at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
Segmentation fault (core dumped)

[rezural]

I have isolated this into a unit test, which shows the problematic behaviour:

#33

Cheers