[FIX] finalize the copper list before propagating monitor error by makeecat · Pull Request #724 · copper-project/copper-rs

makeecat · 2026-01-24T15:19:39Z

Summary

This PR Ensures copperlist finalization (end_of_processing) happens before propagating monitor errors by deferring monitor.process_copperlist error handling.

Issue

when you quit an example app (cu-rp-balancebot) with cu-consolemon, it will crash with a backtrace of log as below.
The panic is caused by the monitor returning Err("Exiting...") on q, which short‑circuits run_one_iteration before the copper list is finalized. That leaks the list, and after a few frames you hit Ran out of space for copper lists.

Details

core/cu29_derive/src/lib.rs: store the result of monitor.process_copperlist(...) in monitor_result, finalize processing (cl_manager.end_of_processing, kf_manager.end_of_processing where applicable), then return monitor_result? across the main runtime path and all abort branches in task/bridge execution.

Backtrace log

reproduce: cargo run -p cu-rp-balancebot on commit c0a3859, then hit 'q' to exit the app.

  Simulation stopped: Exiting...
     context:None
  Simulation stopped: Exiting...
     context:None
  CuConsoleMon panic: panicked at examples/cu_rp_balancebot/src/sim.rs:23:1:
  Ran out of space for copper lists
  Backtrace:
     0: std::backtrace_rs::backtrace::libunwind::trace
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/../../backtrace/src/backtrace/libunwind.rs:117:9
     1: std::backtrace_rs::backtrace::trace_unsynchronized
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/../../backtrace/src/backtrace/mod.rs:66:14
     2: std::backtrace::Backtrace::create
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/backtrace.rs:331:13
     3: cu_consolemon::init_error_hooks::{{closure}}
               at ./components/monitors/cu_consolemon/src/lib.rs:2148:18
     4: <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/alloc/src/boxed.rs:2220:9
     5: std::panicking::panic_with_hook
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/panicking.rs:833:13
     6: std::panicking::panic_handler::{{closure}}
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/panicking.rs:698:13
     7: std::sys::backtrace::__rust_end_short_backtrace
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/sys/backtrace.rs:176:18
     8: __rustc::rust_begin_unwind
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/panicking.rs:689:5
     9: core::panicking::panic_fmt
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/core/src/panicking.rs:80:14
    10: core::panicking::panic_display
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/core/src/panicking.rs:259:5
    11: core::option::expect_failed
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/core/src/option.rs:2184:5
    12: core::option::Option<T>::expect
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/option.rs:971:21
    13: <balancebot_sim::default::BalanceBotSim as cu29_runtime::app::CuSimApplication<S,L>>::run_one_iteration
               at ./examples/cu_rp_balancebot/src/sim.rs:23:1
    14: balancebot_sim::default::BalanceBotSim::run_one_iteration
               at ./examples/cu_rp_balancebot/src/sim.rs:23:1
    15: balancebot_sim::run_copper_callback
               at ./examples/cu_rp_balancebot/src/sim.rs:202:45
    16: core::ops::function::FnMut::call_mut
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/
  function.rs:166:5
    17: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &mut F>::call_mut
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/
  function.rs:298:21
    18: <Func as bevy_ecs::system::function_system::SystemParamFunction<fn(F0,F1,F2,F3,F4,F5) .> Out>>::run::call_inner
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_ecs-0.18.0/src/system/
  function_system.rs:903:21
    19: <Func as bevy_ecs::system::function_system::SystemParamFunction<fn(F0,F1,F2,F3,F4,F5) .> Out>>::run
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_ecs-0.18.0/src/system/
  function_system.rs:906:17
    20: <bevy_ecs::system::function_system::FunctionSystem<Marker,In,Out,F> as bevy_ecs::system::system::System>::run_unsafe
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_ecs-0.18.0/src/system/
  function_system.rs:681:29
    21: bevy_ecs::schedule::executor::__rust_begin_short_backtrace::run_unsafe
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_ecs-0.18.0/src/schedule/executor/
  mod.rs:264:38
    22: bevy_ecs::schedule::executor::multi_threaded::ExecutorState::spawn_system_task::{{closure}}::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_ecs-0.18.0/src/schedule/executor/
  multi_threaded.rs:688:25
    23: core::ops::function::FnOnce::call_once
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/
  function.rs:250:5
    24: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/panic/
  unwind_safe.rs:274:9
    25: std::panicking::catch_unwind::do_call
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:581:40
    26: ___rust_try
    27: std::panicking::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:544:19
    28: std::panic::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:359:14
    29: bevy_ecs::schedule::executor::multi_threaded::ExecutorState::spawn_system_task::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_ecs-0.18.0/src/schedule/executor/
  multi_threaded.rs:681:23
    30: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::future::future::Future>::poll
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/panic/
  unwind_safe.rs:299:9
    31: <futures_lite::future::CatchUnwind<F> as core::future::future::Future>::poll::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/futures-lite-2.6.1/src/future.rs:653:53
    32: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/panic/
  unwind_safe.rs:274:9
    33: std::panicking::catch_unwind::do_call
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:581:40
    34: ___rust_try
    35: std::panicking::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:544:19
    36: std::panic::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:359:14
    37: <futures_lite::future::CatchUnwind<F> as core::future::future::Future>::poll
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/futures-lite-2.6.1/src/future.rs:653:9
    38: <async_executor::AsyncCallOnDrop<Fut,Cleanup> as core::future::future::Future>::poll
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-executor-1.13.3/src/lib.rs:1197:31
    39: async_task::raw::RawTask<F,T,S,M>::run::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-task-4.7.1/src/raw.rs:550:21
    40: core::ops::function::FnOnce::call_once
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/
  function.rs:250:5
    41: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/panic/
  unwind_safe.rs:274:9
    42: std::panicking::catch_unwind::do_call
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:581:40
    43: ___rust_try
    44: std::panicking::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:544:19
    45: std::panic::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:359:14
    46: async_task::raw::RawTask<F,T,S,M>::run
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-task-4.7.1/src/raw.rs:549:23
    47: async_task::runnable::Runnable<M>::run
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-task-4.7.1/src/runnable.rs:781:18
    48: async_executor::State::run::{{closure}}::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-executor-1.13.3/src/lib.rs:751:30
    49: <futures_lite::future::Or<F1,F2> as core::future::future::Future>::poll
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/futures-lite-2.6.1/src/future.rs:454:46
    50: async_executor::State::run::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-executor-1.13.3/src/lib.rs:758:32
    51: async_executor::Executor::run::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/async-executor-1.13.3/src/lib.rs:344:34
    52: futures_lite::future::block_on::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/futures-lite-2.6.1/src/future.rs:96:35
    53: std::thread::local::LocalKey<T>::try_with
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/thread/
  local.rs:513:12
    54: std::thread::local::LocalKey<T>::with
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/thread/
  local.rs:477:20
    55: futures_lite::future::block_on
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/futures-lite-2.6.1/src/future.rs:75:11
    56: bevy_tasks::task_pool::TaskPool::new_internal::{{closure}}::{{closure}}::{{closure}}::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_tasks-0.18.0/src/task_pool.rs:203:37
    57: std::panicking::catch_unwind::do_call
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:581:40
    58: ___rust_try
    59: std::panicking::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:544:19
    60: std::panic::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:359:14
    61: bevy_tasks::task_pool::TaskPool::new_internal::{{closure}}::{{closure}}::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_tasks-0.18.0/src/task_pool.rs:197:43
    62: std::thread::local::LocalKey<T>::try_with
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/thread/
  local.rs:513:12
    63: std::thread::local::LocalKey<T>::with
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/thread/
  local.rs:477:20
    64: bevy_tasks::task_pool::TaskPool::new_internal::{{closure}}::{{closure}}
               at /Users/yang/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_tasks-0.18.0/src/task_pool.rs:190:50
    65: std::sys::backtrace::__rust_begin_short_backtrace
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/
  backtrace.rs:160:18
    66: std::thread::lifecycle::spawn_unchecked::{{closure}}::{{closure}}
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/thread/
  lifecycle.rs:92:13
    67: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/panic/
  unwind_safe.rs:274:9
    68: std::panicking::catch_unwind::do_call
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:581:40
    69: ___rust_try
    70: std::panicking::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/
  panicking.rs:544:19
    71: std::panic::catch_unwind
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:359:14
    72: std::thread::lifecycle::spawn_unchecked::{{closure}}
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/thread/
  lifecycle.rs:90:26
    73: core::ops::function::FnOnce::call_once{{vtable.shim}}
               at /Users/yang/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/
  function.rs:250:5
    74: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/alloc/src/boxed.rs:2206:9
    75: std::sys::thread::unix::Thread::new::thread_start
               at /rustc/254b59607d4417e9dffbc307138ae5c86280fe4c/library/std/src/sys/thread/unix.rs:118:17
    76: __pthread_cond_wait

[FIX] finalize the copper list before propagating monitor error

1cea560

makeecat requested a review from gbin January 24, 2026 15:19

makeecat self-assigned this Jan 24, 2026

makeecat added the bug Something isn't working label Jan 24, 2026

gbin merged commit 65e7c23 into master Jan 24, 2026
23 checks passed

gbin deleted the yang/fix/panic_monitoring_exit branch January 24, 2026 23:07

makeecat added the include in changelog label Jan 27, 2026

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[FIX] finalize the copper list before propagating monitor error#724

[FIX] finalize the copper list before propagating monitor error#724
gbin merged 1 commit into
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yang/fix/panic_monitoring_exit

makeecat commented Jan 24, 2026

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makeecat commented Jan 24, 2026

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