Method promiseRejectionTracker

src/JobQueue.cc:130–165

}

void JobQueue::promiseRejectionTracker(JSContext *cx,
  bool mutedErrors,
  JS::HandleObject promise,
  JS::PromiseRejectionHandlingState state,
  [[maybe_unused]] void *privateData) {

  // We only care about unhandled Promises
  if (state != JS::PromiseRejectionHandlingState::Unhandled) {
    return;
  }
  // If the `mutedErrors` option is set to True in `pm.eval`, eval errors or unhandled rejections should be ignored.
  if (mutedErrors) {
    return;
  }

  // Test if there's no user-defined (or pmjs defined) exception handler on the Python event-loop
  PyEventLoop loop = PyEventLoop::getRunningLoop();
  if (!loop.initialized()) return;
  PyObject *customHandler = PyObject_GetAttrString(loop._loop, "_exception_handler"); // see https://github.com/python/cpython/blob/v3.9.16/Lib/asyncio/base_events.py#L1782
  if (customHandler == Py_None) { // we only have the default exception handler
    // Set an exception handler to the event-loop
    PyObject *pmModule = PyImport_ImportModule("pythonmonkey");
    PyObject *exceptionHandler = PyObject_GetAttrString(pmModule, "simpleUncaughtExceptionHandler");
    PyObject_CallMethod(loop._loop, "set_exception_handler", "O", exceptionHandler);
    Py_DECREF(pmModule);
    Py_DECREF(exceptionHandler);
  }
  Py_DECREF(customHandler);

  // Go ahead and send this unhandled Promise rejection to the exception handler on the Python event-loop
  PyObject *pyFuture = PromiseType::getPyObject(cx, promise); // ref count == 2
  // Unhandled Future object calls the event-loop exception handler in its destructor (the `__del__` magic method)
  // See https://github.com/python/cpython/blob/v3.9.16/Lib/asyncio/futures.py#L108
  //  or https://github.com/python/cpython/blob/v3.9.16/Modules/_asynciomodule.c#L1457-L1467 (It will actually use the C module by default, see futures.py#L417-L423)
  Py_DECREF(pyFuture); // decreasing the reference count from 2 to 1, leaving one for the `onResolved` callback in `PromiseType::getPyObject`, which will be called very soon and clean up the reference
}

void JobQueue::queueFinalizationRegistryCallback(JSFunction *callback) {
  mozilla::Unused << finalizationRegistryCallbacks->append(callback);