JMS Serializer add groups by some condition

[shubaivan]

I have entity Notification and when my entity contain some condition I want add additional groups for serializer, I create event serializer.pre_serialize for Notification and after check condition add additional groups in serialized context, but in response it's not works. Example I want add some nested to my Notification it would be some another Entity, example Question and this entity have some groups, and after set it when I create context SerializationContext::create() everything work, but when I try add additional group in serializer.pre_serialize it's not work

this my entity

class Notifications
{
use TraitTimestampable;

const GROUP_POST_NOTIFICATION = 'post_notifications';
const GROUP_GET_NOTIFICATIONS = 'get_notifications';

/**
 * @ORM\Column(type="integer")
 * @ORM\Id
 * @ORM\GeneratedValue(strategy="AUTO")
 * @Annotation\Groups({
 *     "get_notifications"
 * })
 */
private $id;

/**
 * @var object
 *
 * @Annotation\Groups({
 *     "get_notifications"
 * })
 */
private $providerEntity;

and another entity which I adding in event

class Questions implements NotificationInterface
{
use TraitTimestampable;
const GROUP_POST = 'post_question';
const GROUP_GET = 'get_question';

/**
 * @ORM\Column(type="integer")
 * @ORM\Id
 * @ORM\GeneratedValue(strategy="AUTO")
 * @Annotation\Groups({
 *     "get_question"
 * })
 */
private $id;

    /**
 * @return array
 */
public static function getGetGroup()
{
    return [self::GROUP_GET];
}

but in response I have

public function onPreSerializeNotifications(PreSerializeEvent $event) 
{
    /** @var Notifications $notifications*/
    $notifications = $event->getObject();
    $provider = $notifications->getProvider(); //this is Questions::class
    $this->providerEntity = $this->entityManager->getRepository($provider)
        ->findOneBy(['id' => $notifications->getProviderId()]);
    $notifications->setProviderEntity($this->providerEntity);

    $attr = $event->getContext()->attributes;
    $groups = array_merge($attr->all()['groups'], $provider::getGetGroup());
    $attr->set('groups', $groups);
}

but in response I have

"notifications": [
   {
      "id": 2,
      "provider_entity": {}
   }
]

why ?

[goetas]

You can not edit the context once the serialization is started. The context should be immutable. In 2.x $attr->set will be removed (to avoid confusion as you are facing)

[shubaivan]

@goetas ok, if I correct understand I don't have opportunity add additional group by some condition ?

[goetas]

Not really, you can use other type of exclusion strategies, see: https://github.com/schmittjoh/serializer/blob/master/doc/cookbook/exclusion_strategies.rst#dynamic-exclusion-strategy as example