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fix(events): drop orphaned native-async token after synchronous events.once settle #5191

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Merged
proggeramlug merged 2 commits into from
Jun 15, 2026
Merged

fix(events): drop orphaned native-async token after synchronous events.once settle #5191

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88fae3e
fix(events): drop orphaned native-async token after synchronous event…
Jun 15, 2026
d60e36b
chore(events): move events.once listener trampolines to module_iterators
Jun 15, 2026
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83 changes: 20 additions & 63 deletions crates/perry-ext-events/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -48,8 +48,9 @@ use target_helpers::{
};
mod module_iterators;
use module_iterators::{
events_on_abort_listener, events_on_queue_listener, events_once_event_target_listener,
first_rest_arg_or_undefined, rest_array_or_empty,
events_on_abort_listener, events_on_queue_listener, events_once_abort_listener,
events_once_event_target_listener, events_once_stream_reject_listener,
events_once_stream_resolve_listener,
};

const MIN_HEAP_POINTER: u64 = 0x1000;
Expand Down Expand Up @@ -81,6 +82,15 @@ extern "C" {
);
fn js_promise_resolve(promise: *mut Promise, value: f64);
fn js_promise_reject(promise: *mut Promise, reason: f64);
// events.once allocates its Promise via perry-ffi's `JsPromise::new()`
// (→ `perry_ffi_promise_new` → a registered native-async token that pins
// the Promise and reports the event loop as "busy"). Because we settle
// synchronously through `js_promise_resolve`/`js_promise_reject` above —
// bypassing the deferred completion machinery that would normally retire
// the token — the token leaks and `js_native_async_has_active()` keeps the
// loop alive forever (the `events.once(em, name)` + `emit` hang). Drop the
// orphaned token right after each synchronous settle.
fn js_native_async_drop_promise_token(promise: *mut Promise);
fn js_promise_then(
promise: *mut Promise,
on_fulfilled: *mut RawClosureHeader,
Expand Down Expand Up @@ -1092,6 +1102,7 @@ unsafe fn drain_pending_once_promises(
// Synchronous resolve — see the comment on the extern at the
// top of this file for why we bypass `JsPromise::resolve`.
js_promise_resolve(pending.promise, f64::from_bits(bits));
js_native_async_drop_promise_token(pending.promise);
}
}

Expand All @@ -1114,6 +1125,7 @@ unsafe fn reject_pending_once_promises_for_error(
cleanup_pending_abort_listener(&pending);
if !pending.promise.is_null() {
js_promise_reject(pending.promise, error_value);
js_native_async_drop_promise_token(pending.promise);
rejected_any = true;
}
}
Expand Down Expand Up @@ -1562,69 +1574,11 @@ pub unsafe extern "C" fn js_event_emitter_raw_listeners(
// Module-level helpers — `events.once(em, name)` / `events.on(em, name)` /
// `events.getEventListeners(em, name)` / `events.listenerCount(em, name)` /
// `events.setMaxListeners(n, em)` / `events.getMaxListeners(em)`.
// The `events.once` listener trampolines (abort / stream-resolve /
// stream-reject) live in `module_iterators.rs` alongside
// `events_once_event_target_listener`.
// ============================================================================

extern "C" fn events_once_abort_listener(closure: *const RawClosureHeader) -> f64 {
unsafe {
let handle = js_closure_get_capture_ptr(closure, 0) as Handle;
let promise = js_closure_get_capture_ptr(closure, 1) as *mut Promise;
let pending = get_event_emitter_mut(handle)
.and_then(|emitter| remove_pending_once_promise(emitter, promise));
if let Some(pending) = pending {
cleanup_pending_abort_listener(&pending);
if !pending.promise.is_null() {
js_promise_reject(pending.promise, js_abort_error_value());
}
}
}
undefined_value()
}

extern "C" fn events_once_stream_resolve_listener(
closure: *const RawClosureHeader,
rest: f64,
) -> f64 {
unsafe {
let promise = js_closure_get_capture_ptr(closure, 0) as *mut Promise;
let handle = js_closure_get_capture_ptr(closure, 1) as Handle;
let error_listener = js_closure_get_capture_ptr(closure, 2);
let error_event_ptr = js_closure_get_capture_ptr(closure, 3);
if promise.is_null() {
return undefined_value();
}
if handle != 0 && error_listener != 0 && error_event_ptr != 0 {
let error_event =
f64::from_bits(nanbox_string_bits(error_event_ptr as *mut StringHeader));
let error_listener_value = nanbox_pointer_bits(error_listener);
let _ =
js_node_stream_method_remove_listener(handle, error_event, error_listener_value);
}
js_promise_resolve(promise, rest_array_or_empty(rest));
}
undefined_value()
}

extern "C" fn events_once_stream_reject_listener(
closure: *const RawClosureHeader,
rest: f64,
) -> f64 {
unsafe {
let promise = js_closure_get_capture_ptr(closure, 0) as *mut Promise;
let handle = js_closure_get_capture_ptr(closure, 1) as Handle;
let event_name_ptr = js_closure_get_capture_ptr(closure, 2);
let resolve_listener = js_closure_get_capture_ptr(closure, 3);
if handle != 0 && event_name_ptr != 0 && resolve_listener != 0 {
let event = f64::from_bits(nanbox_string_bits(event_name_ptr as *mut StringHeader));
let resolve_listener_value = nanbox_pointer_bits(resolve_listener);
let _ = js_node_stream_method_remove_listener(handle, event, resolve_listener_value);
}
if !promise.is_null() {
js_promise_reject(promise, first_rest_arg_or_undefined(rest));
}
}
undefined_value()
}

/// `events.once(emitter, eventName[, options])` — returns a Promise that resolves
/// to the args array from the next matching event.
///
Expand All @@ -1651,6 +1605,7 @@ pub unsafe extern "C" fn js_events_once(
target_value,
)),
);
js_native_async_drop_promise_token(raw);
return raw;
}
};
Expand All @@ -1661,11 +1616,13 @@ pub unsafe extern "C" fn js_events_once(
Ok(signal) => signal,
Err(error) => {
js_promise_reject(raw, error);
js_native_async_drop_promise_token(raw);
return raw;
}
};
if signal.is_some_and(signal_is_aborted) {
js_promise_reject(raw, js_abort_error_value());
js_native_async_drop_promise_token(raw);
return raw;
}
if let EventHelperTarget::EventEmitter(handle) = target {
Expand Down
65 changes: 65 additions & 0 deletions crates/perry-ext-events/src/module_iterators.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,71 @@ pub(super) extern "C" fn events_once_event_target_listener(
let mut args = js_array_alloc(0);
args = js_array_push_f64(args, arg0);
js_promise_resolve(promise, nanbox_pointer_bits(args as i64));
js_native_async_drop_promise_token(promise);
}
}
undefined_value()
}

pub(super) extern "C" fn events_once_abort_listener(closure: *const RawClosureHeader) -> f64 {
unsafe {
let handle = js_closure_get_capture_ptr(closure, 0) as Handle;
let promise = js_closure_get_capture_ptr(closure, 1) as *mut Promise;
let pending = get_event_emitter_mut(handle)
.and_then(|emitter| remove_pending_once_promise(emitter, promise));
if let Some(pending) = pending {
cleanup_pending_abort_listener(&pending);
if !pending.promise.is_null() {
js_promise_reject(pending.promise, js_abort_error_value());
js_native_async_drop_promise_token(pending.promise);
}
}
}
undefined_value()
}

pub(super) extern "C" fn events_once_stream_resolve_listener(
closure: *const RawClosureHeader,
rest: f64,
) -> f64 {
unsafe {
let promise = js_closure_get_capture_ptr(closure, 0) as *mut Promise;
let handle = js_closure_get_capture_ptr(closure, 1) as Handle;
let error_listener = js_closure_get_capture_ptr(closure, 2);
let error_event_ptr = js_closure_get_capture_ptr(closure, 3);
if promise.is_null() {
return undefined_value();
}
if handle != 0 && error_listener != 0 && error_event_ptr != 0 {
let error_event =
f64::from_bits(nanbox_string_bits(error_event_ptr as *mut StringHeader));
let error_listener_value = nanbox_pointer_bits(error_listener);
let _ =
js_node_stream_method_remove_listener(handle, error_event, error_listener_value);
}
js_promise_resolve(promise, rest_array_or_empty(rest));
js_native_async_drop_promise_token(promise);
}
undefined_value()
}

pub(super) extern "C" fn events_once_stream_reject_listener(
closure: *const RawClosureHeader,
rest: f64,
) -> f64 {
unsafe {
let promise = js_closure_get_capture_ptr(closure, 0) as *mut Promise;
let handle = js_closure_get_capture_ptr(closure, 1) as Handle;
let event_name_ptr = js_closure_get_capture_ptr(closure, 2);
let resolve_listener = js_closure_get_capture_ptr(closure, 3);
if handle != 0 && event_name_ptr != 0 && resolve_listener != 0 {
let event = f64::from_bits(nanbox_string_bits(event_name_ptr as *mut StringHeader));
let resolve_listener_value = nanbox_pointer_bits(resolve_listener);
let _ = js_node_stream_method_remove_listener(handle, event, resolve_listener_value);
}
if !promise.is_null() {
js_promise_reject(promise, first_rest_arg_or_undefined(rest));
js_native_async_drop_promise_token(promise);
}
}
undefined_value()
Expand Down
5 changes: 3 additions & 2 deletions crates/perry-runtime/src/promise/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,9 @@ pub use native_async::{
js_native_async_completion_new, js_native_async_completion_promise,
js_native_async_completion_reject_bits, js_native_async_completion_reject_promise_bits,
js_native_async_completion_reject_string, js_native_async_completion_resolve_bits,
js_native_async_completion_resolve_promise_bits, js_native_async_has_active,
js_native_async_process_pending, scan_native_async_completion_roots_mut, NativeAsyncCompletion,
js_native_async_completion_resolve_promise_bits, js_native_async_drop_promise_token,
js_native_async_has_active, js_native_async_process_pending,
scan_native_async_completion_roots_mut, NativeAsyncCompletion,
PERRY_NATIVE_ASYNC_ALREADY_COMPLETED, PERRY_NATIVE_ASYNC_CLEANUP_ON_CANCEL,
PERRY_NATIVE_ASYNC_CLEANUP_ON_REJECT, PERRY_NATIVE_ASYNC_CLEANUP_ON_SUCCESS,
PERRY_NATIVE_ASYNC_INVALID, PERRY_NATIVE_ASYNC_OK, PERRY_NATIVE_ASYNC_THREAD_MAIN,
Expand Down
32 changes: 32 additions & 0 deletions crates/perry-runtime/src/promise/native_async.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -482,6 +482,38 @@ pub extern "C" fn js_native_async_process_pending() -> i32 {
processed
}

/// Drop the native-async completion token associated with a Promise that was
/// settled *synchronously* (via `js_promise_resolve`/`js_promise_reject`)
/// outside the deferred completion machinery.
///
/// Ext crates such as `perry-ext-events` allocate their `events.once` Promise
/// through perry-ffi's `JsPromise::new()` → `perry_ffi_promise_new()`, which
/// registers a native-async token (and pins the Promise) so a worker can
/// resolve it later. `events.once`, however, settles synchronously from
/// `emit(...)` and deliberately bypasses the deferred resolve path (see the
/// extern comment in perry-ext-events). That bypass never runs
/// `js_native_async_process_pending`, so the token stays in the registry
/// forever and `js_native_async_has_active()` keeps reporting work — the
/// process hangs after the awaited event already fired (the
/// `events.once(emitter, name)` + `emit` hang). Calling this right after the
/// synchronous settle removes the orphaned token (mirroring the cleanup
/// `js_native_async_process_pending` performs) so the event loop can drain.
#[no_mangle]
pub extern "C" fn js_native_async_drop_promise_token(promise: *mut Promise) {
if promise.is_null() {
return;
}
let token_ptr = {
let registry = crate::gc::lock_gc_root_registry(registry());
registry.by_promise.get(&(promise as usize)).copied()
};
if let Some(token_ptr) = token_ptr {
let token = unsafe { &*(token_ptr as *const NativeAsyncCompletion) };
token.state.store(STATE_COMPLETED, Ordering::Release);
remove_token_from_registry(token_ptr, promise as usize);
}
}

/// Return 1 while there are live or queued native async completions.
#[no_mangle]
pub extern "C" fn js_native_async_has_active() -> i32 {
Expand Down
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