Entity listeners: what's the difference between passed object and event arguments object

[ToshY]

I'm looking at the documentation regarding "Entity Listeners", and I see the following example for preUpdate:

<?php
use Doctrine\ORM\Event\PreUpdateEventArgs;

class UserListener
{
    public function preUpdate(User $user, PreUpdateEventArgs $event)
    {
        // Do something on pre update.
    }
}

The explanation above that example denotes the following:

An entity listener method receives two arguments, the entity instance and the lifecycle event.

My question:

• What's the difference between the first argument $user and if would get the object from the event arguments, $event->getObject() ?
  1. If there's a difference, what is it?
  2. If there isn't difference, why is there a first argument?

[javaDeveloperKid]

Yes, they are the same. You can see it in UnitOfWork::executeUpdates where the event is dispatched or just check it yourself with === comparison. I don't know why this is that way but there might be no reason and this is still fine.

[ToshY]

Thank you for the confirmation.