Unexpected non-iterable value for to-many relation

[pesseyjulien]

Hi,

Updated to the latest version (2.5.2), and now I'm getting the following error :

Symfony\Component\Serializer\Exception\UnexpectedValueException: Unexpected non-iterable value for to-many relation.
#9 /vendor/api-platform/core/src/Serializer/AbstractItemNormalizer.php(526): ApiPlatform\Core\Serializer\AbstractItemNormalizer::getAttributeValue
#8 /vendor/symfony/symfony/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php(181): Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer::normalize
#7 /vendor/api-platform/core/src/Serializer/AbstractItemNormalizer.php(151): ApiPlatform\Core\Serializer\AbstractItemNormalizer::normalize
#6 /vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php(152): Symfony\Component\Serializer\Serializer::normalize
#5 /vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php(125): Symfony\Component\Serializer\Serializer::serialize
#4 /src/AppBundle/Controller/JobController.php(90): AppBundle\Controller\JobController::createJobAction
#3 /vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php(151): Symfony\Component\HttpKernel\HttpKernel::handleRaw
#2 /vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel::handle
#1 /vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Kernel.php(198): Symfony\Component\HttpKernel\Kernel::handle
#0 /public/index.php(24): null

Any idea why ?

[teohhanhui]

Could you share what this value is? Might be a regression introduced in #3248

[pesseyjulien]

No idea, here is the issue : https://sentry.io/share/issue/0062c90e3b27452ab8fb207489ee6d04/

test Data sent :

--data "{"category":"v2_pastryCook","end_date":"2019-11-28T18:00:00.000Z","skills":[{"code":"cocktail-bar","level":0},{"code":"bar","level":0},{"code":"store","level":0},{"code":"brasserie","level":0},{"code":"candy","level":0},{"code":"barista","level":0},{"code":"vegan","level":0},{"code":"english","level":0},{"code":"mixologie","level":0},{"code":"bread-viennoiserie","level":0},{"code":"chocolat","level":0},{"code":"sugar","level":0},{"code":"traditional","level":0},{"code":"caterer","level":0},{"code":"shaved","level":0},{"code":"trimmed","level":0},{"code":"security-shoe","level":0},{"code":"knife","level":0},{"code":"light-clothes","level":0},{"code":"dark-clothes","level":0},{"code":"hat","level":0}],"company":"f68eb899-7619-4f34-827c-fb9b86c1a38a","total_worked_minutes":420,"rate_unit":"eurPerHour","requested_applicant_number":1,"start_date":"2019-11-28T11:00:00.000Z"}" \

[teohhanhui]

Maybe some dump calls would help in debugging this.

[pesseyjulien]

For now I have downgraded to the previous version, I will try some calls later and I will let you know. thanks !

Just confirming that I've seen the same issue. Downgrading to 2.5.1 fixed it. Also #followResponses

[soyuka]

Can you give us the related entity and if there's some additional data to reproduce (POST with data X), thanks!

I've attached the swagger docs and the v2.5.1 json output for the document thats failing.

Archive.zip

FYI We're using MongoDB (Doctrine ODM).

Output message below:

{
  "message": "Unexpected non-iterable value for to-many relation.",
  "status": 400,
  "title": "Bad Request",
  "trace": [
    "Line 176: \\ApiPlatform\\Core\\Serializer\\AbstractItemNormalizer::getAttributeValue",
    "Line 151: \\Symfony\\Component\\Serializer\\Normalizer\\AbstractObjectNormalizer::normalize",
    "Line 146: \\ApiPlatform\\Core\\Serializer\\AbstractItemNormalizer::normalize",
    "Line 119: \\Symfony\\Component\\Serializer\\Serializer::normalize",
    "Line 95: \\Symfony\\Component\\Serializer\\Serializer::serialize",
    "Line 126: \\ApiPlatform\\Core\\EventListener\\SerializeListener::onKernelView",
    "Line 264: \\Symfony\\Component\\EventDispatcher\\Debug\\WrappedListener::__invoke",
    "Line 239: \\Symfony\\Component\\EventDispatcher\\EventDispatcher::doDispatch",
    "Line 73: \\Symfony\\Component\\EventDispatcher\\EventDispatcher::callListeners",
    "Line 168: \\Symfony\\Component\\EventDispatcher\\EventDispatcher::dispatch",
    "Line 151: \\Symfony\\Component\\EventDispatcher\\Debug\\TraceableEventDispatcher::dispatch",
    "Line 68: \\Symfony\\Component\\HttpKernel\\HttpKernel::handleRaw",
    "Line 201: \\Symfony\\Component\\HttpKernel\\HttpKernel::handle",
    "Line 28: \\Symfony\\Component\\HttpKernel\\Kernel::handle"
  ]
}

[bastnic]

Hmm, just checking in on this error.

class MyEntity
{
    /**
     * @var Collection|Workspace[]
     *
     * @ORM\ManyToMany(targetEntity="Workspace", inversedBy="XXXX")
     */
    private $workspaces;

    public function getWorkspace()
    {
        return $this->workspaces->first();
    }

    public function getWorkspaces()
    {
        return $this->workspaces;
    }

} 

App\Entity\MyEntity:
  attributes:
    workspace:
      groups: ['myEntity:read']
    workspaces:
      groups: ['myEntity:read']

If I rename my method to firstWorkspace and change it in the serialization, it works. I find it to suspect that I tried with another collection, just creating a method that is the singular of the collection name and bam.

Here $type is seen as an array for workspace but $attributeValue is a Workspace as it should be. So not iterable, and it crashes with Unexpected non-iterable value for to-many relation..

[teohhanhui]

@bastnic In your case it doesn't seem like a bug in our code. Symfony PropertyAccess / PropertyInfo (I haven't investigated which one) is confused because you don't follow the naming conventions.

[bastnic]

@teohhanhui you can consider it's a regression so.

It worked before as expected (returning a Workspace) and now throw an error. Maybe, if not a collection, just bypass that piece of code ?

[teohhanhui]

It's a bug fix, not a regression. It was never supposed to work. Getting a resource object when we're expecting a collection just makes no sense, and trying to bypass things just makes our code more complicated for no reason.

[bastnic]

Still, it's not a collection, and before it was returning something correct and now not. I understand that this is an underlying bug (or feature, I will check) in Symfony not an APIP one.

I'm in a position where I can investigate and fix thing. So it's already old news and it's fixed since a long time on my side. But 2.5.2 is a minor release, at least 3 persons experience it and the only information we got is Unexpected non-iterable value for to-many relation. Maybe we should specify in the error where it happens property X of entity Y is supposed to be a collection but it's not