AbstractVisitor::getElementType() must be of the type array or null, string returned

[iaejean]

Q	A
Bug report?	yes
Feature request?	no
BC Break report?	no
RFC?	no

I'm getting the follow message Return value of JMS\Serializer\AbstractVisitor::getElementType() must be of the type array or null, string returned when I'm trying to serialize an object.

Steps required to reproduce the problem

1. I have a estructure similar to:

/**
 * @Serializer\Discriminator(
 *     disabled=true,
 *     field="type",
 *     map={
 *         "Company": "Company",
 *         "Branch":     "Branch"
 *     }
 * )
 */
abstract class AbstractModel {}

class Company extend AbstractModel {}

class Branch extend AbstractModel {}

class Link  {

   /**
     * @Serializer\Type("string")
     */
    private $next;

    /**
     * @Serializer\Type("string")
     */
    private $prev;
}

class Pagination
{
    /**
     * @Serializer\Type("Link")
     */
    private $links;

    /**
     * @Serializer\Type("integer")
     */
    private $limit;

    /**
     * @Serializer\Type("integer")
     */
    private $size;

    /**
     * @Serializer\Type("integer")
     */
    private $start;

    /**
     * @Serializer\Type("integer")
     */
    private $total;

    /**
     * @Serializer\Type("ArrayCollection<AbstractModel>")
     */
    private $results;
}

Expected Result

{
    "links": {},
    "limit": 20,
    "size": 1,
    "start": 1,
    "total": 1,
    "results": [
        {
            "id": 1,
            "name": "My Branch",
            "picture": "url",
            "address": "",
            "phone": "",
            "longitude": "",
            "latitude": "",
            "company": {
                "id": 1,
                "name": "My Compay",
                "picture": "url picture",
                "description": "",
                "website": "url website",
                "logo": "url log",
                "address": "",
                "phone": "",
                "latitude": "",
                "longitude": ""
            },
            "category": [
                {
                    "name": "Games",
                    "description": "Games",
                    "restaurant": []
                },
                {
                    "name": "Familiar",
                    "description": "Familiar",
                    "restaurant": []
                }
            ]
        }
    ]
}

Actual Result

Message: Return value of JMS\Serializer\AbstractVisitor::getElementType() must be of the type array or null, string returned

[goetas]

can you post please the stack trace?

[iaejean]

@goetas
If I print the value of $typeArray when crash I get the follow data:

Then I've added
a print to get the stack trace

AbstractVisitor at line 39:

    if (isset($typeArray['params'][0]) && !\is_array($typeArray['params'][0])) {
        dd(debug_print_backtrace(30));
    }

#0  JMS\Serializer\AbstractVisitor->getElementType() called at [/my-project/vendor/jms/serializer/src/JsonSerializationVisitor.php:90]
#1  JMS\Serializer\JsonSerializationVisitor->visitArray() called at [/my-project/vendor/jms/serializer/src/Handler/ArrayCollectionHandler.php:81]
#2  JMS\Serializer\Handler\ArrayCollectionHandler->serializeCollection() called at [/my-project/vendor/jms/serializer/src/GraphNavigator/SerializationGraphNavigator.php:192]
#3  JMS\Serializer\GraphNavigator\SerializationGraphNavigator->accept() called at [/my-project/vendor/jms/serializer/src/JsonSerializationVisitor.php:136]
#4  JMS\Serializer\JsonSerializationVisitor->visitProperty() called at [/my-project/vendor/jms/serializer/src/GraphNavigator/SerializationGraphNavigator.php:234]
#5  JMS\Serializer\GraphNavigator\SerializationGraphNavigator->accept() called at [/my-project/vendor/jms/serializer/src/JsonSerializationVisitor.php:93]
#6  JMS\Serializer\JsonSerializationVisitor->visitArray() called at [/my-project/vendor/jms/serializer/src/Handler/ArrayCollectionHandler.php:81]
#7  JMS\Serializer\Handler\ArrayCollectionHandler->serializeCollection() called at [/my-project/vendor/jms/serializer/src/GraphNavigator/SerializationGraphNavigator.php:192]
#8  JMS\Serializer\GraphNavigator\SerializationGraphNavigator->accept() called at [/my-project/vendor/jms/serializer/src/JsonSerializationVisitor.php:136]
#9  JMS\Serializer\JsonSerializationVisitor->visitProperty() called at [/my-project/vendor/jms/serializer/src/GraphNavigator/SerializationGraphNavigator.php:234]
#10 JMS\Serializer\GraphNavigator\SerializationGraphNavigator->accept() called at [/my-project/vendor/jms/serializer/src/JsonSerializationVisitor.php:93]
#11 JMS\Serializer\JsonSerializationVisitor->visitArray() called at [/my-project/vendor/jms/serializer/src/Handler/ArrayCollectionHandler.php:81]
#12 JMS\Serializer\Handler\ArrayCollectionHandler->serializeCollection() called at [/my-project/vendor/jms/serializer/src/GraphNavigator/SerializationGraphNavigator.php:192]
#13 JMS\Serializer\GraphNavigator\SerializationGraphNavigator->accept() called at [/my-project/vendor/jms/serializer/src/JsonSerializationVisitor.php:136]
#14 JMS\Serializer\JsonSerializationVisitor->visitProperty() called at [/my-project/vendor/jms/serializer/src/GraphNavigator/SerializationGraphNavigator.php:234]
#15 JMS\Serializer\GraphNavigator\SerializationGraphNavigator->accept() called at [/my-project/vendor/jms/serializer/src/Serializer.php:249]
#16 JMS\Serializer\Serializer->visit() called at [/my-project/vendor/jms/serializer/src/Serializer.php:162]
#17 JMS\Serializer\Serializer->serialize() called at [/my-project/src/Application/Common/TraitListener.php:86]
#18 App\Application\EventListener\ResponseListener->jsonResponse() called at [/my-project/src/Application/Common/TraitListener.php:69]
#19 App\Application\EventListener\ResponseListener->response() called at [/my-project/src/Application/EventListener/ResponseListener.php:36]
#20 App\Application\EventListener\ResponseListener->onKernelResponse() called at [/my-project/vendor/symfony/event-dispatcher/Debug/WrappedListener.php:111]
#21 Symfony\Component\EventDispatcher\Debug\WrappedListener->__invoke() called at [/my-project/vendor/symfony/event-dispatcher/EventDispatcher.php:212]
#22 Symfony\Component\EventDispatcher\EventDispatcher->doDispatch() called at [/my-project/vendor/symfony/event-dispatcher/EventDispatcher.php:44]
#23 Symfony\Component\EventDispatcher\EventDispatcher->dispatch() called at [/my-project/vendor/symfony/event-dispatcher/Debug/TraceableEventDispatcher.php:142]
#24 Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcher->dispatch() called at [/my-project/vendor/symfony/http-kernel/HttpKernel.php:189]
#25 Symfony\Component\HttpKernel\HttpKernel->filterResponse() called at [/my-project/vendor/symfony/http-kernel/HttpKernel.php:171]
#26 Symfony\Component\HttpKernel\HttpKernel->handleRaw() called at [/my-project/vendor/symfony/http-kernel/HttpKernel.php:67]
#27 Symfony\Component\HttpKernel\HttpKernel->handle() called at [/my-project/vendor/symfony/http-kernel/Kernel.php:198]
#28 Symfony\Component\HttpKernel\Kernel->handle() called at [/my-project/public/index.php:37]

[iaejean]

Basically I just validate if the element isn't array return null, it looks like is working fine

[goetas]

Something is wrong with your type.

You have:

array(
  'name' => 'array',
  'params' => array(
    0 => 'Branch'     
  )
)

but should be

array(
  'name' => 'array',
  'params' => array(
    0 => array(
       'name' => 'Branch',
       'params' => array()
    )
  )
)

Are you using some custom handler where you define the type manually?

[iaejean]

Not, there isn't any custom handler