Function attach_thread

crates/vm/src/vm/thread.rs:153–183

(vm: &VirtualMachine)

#[cfg(all(unix, feature = "threading"))]
fn attach_thread(vm: &VirtualMachine) {
    CURRENT_THREAD_SLOT.with(|slot| {
        if let Some(s) = slot.borrow().as_ref() {
            super::stw_trace(format_args!("attach begin"));
            loop {
                match s.state.compare_exchange(
                    THREAD_DETACHED,
                    THREAD_ATTACHED,
                    Ordering::AcqRel,
                    Ordering::Relaxed,
                ) {
                    Ok(_) => {
                        super::stw_trace(format_args!("attach DETACHED->ATTACHED"));
                        break;
                    }
                    Err(THREAD_SUSPENDED) => {
                        // Parked by stop-the-world — wait until released to DETACHED
                        super::stw_trace(format_args!("attach wait-suspended"));
                        let wait_yields = wait_while_suspended(s);
                        vm.state.stop_the_world.add_attach_wait_yields(wait_yields);
                        // Retry CAS
                    }
                    Err(state) => {
                        debug_assert!(false, "unexpected thread state in attach: {state}");
                        break;
                    }
                }
            }
        }
    });
}

/// Transition ATTACHED → DETACHED (like `_PyThreadState_Detach`).
#[cfg(all(unix, feature = "threading"))]