The form is always empty, why?

Question

symfony

$builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
            $data = $event->getData();
            dump($data);
        });
// or
        $data = $builder->getData();

Always empty after the form is submitted. Although it was filled before etogo, before rendering + data after the output is changed.
Why is that?

Answer 1

Obviously the answer lies in the very name of the event, it is called before the data enters the form. The documentation for this event explicitly states this.