The denormalize method in the ItemNormalizer does not set the resource_class correctly.

[nielsvandermolen]

Stack trace:
In ItemNormalizer.php line 54:

[ErrorException]
Notice: Undefined index: resource_class

Exception trace:
ApiPlatform\Core\Serializer\ItemNormalizer->updateObjectToPopulate() at /var/www/environments/vendor/api-platform/core/src/Serializer/ItemNormalizer.php:42
ApiPlatform\Core\Serializer\ItemNormalizer->denormalize() at /var/www/environments/vendor/symfony/serializer/Serializer.php:179
Symfony\Component\Serializer\Serializer->denormalize() at /var/www/environments/vendor/symfony/serializer/Normalizer/AbstractNormalizer.php:370
Symfony\Component\Serializer\Normalizer\AbstractNormalizer->instantiateObject() at /var/www/environments/vendor/symfony/serializer/Normalizer/AbstractObjectNormalizer.php:143
Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer->instantiateObject() at /var/www/environments/vendor/symfony/serializer/Normalizer/AbstractObjectNormalizer.php:244
Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer->denormalize() at /var/www/environments/vendor/symfony/serializer/Serializer.php:179
Symfony\Component\Serializer\Serializer->denormalize() at /var/www/environments/vendor/symfony/serializer/Serializer.php:128
Symfony\Component\Serializer\Serializer->deserialize() at /var/www/environments/vendor/symfony/messenger/Transport/Serialization/Serializer.php:54`

What triggered this issue:
Using API Platform in combination with the Symfony Message component and encoding an entity that is an APIPlatform resource.

Root cause
In the denormalize method in api-platform/core/src/Serializer/ItemNormalizer.php the resource_class is not set in the context. It seems this is common because it is handled in the AbstractItemNormalizer class line 123:

$context['api_denormalize'] = true;
if (!isset($context['resource_class'])) {
$context['resource_class'] = $class;
}

Unfortunatly, this is called after we need it

        $this->updateObjectToPopulate($data, $context);  // The error is thrown in this method.
    }
    return parent::denormalize($data, $class, $format, $context); // Calls the method in the AbstractClass

Potential solution
Adding the code in the ItemNormalizer instead of the AbstractNormalizer seems to solve the issue.

[Cethy]

I tried setting the resource_class option before calling denormalizer::deserialize but it caused an uncaught circular reference.

Is there a way to use the Serializer and tell api-platform to not do its thing ?

context

• Getting Symfony\Component\Serializer\SerializerInterface via service injection ;
• Deserializing from csv file to php object (marked as @ApiResource) like this :

$this->denormalizer->deserialize(file_get_contents($this->originAbsPath),
    sprintf('%s[]', FluidType::class),
    'csv',
    [
        CsvEncoder::DELIMITER_KEY => ',',
        //'resource_class' => FluidType::class
    ]
);

other potential solution (what worked for me)
in ApiPlatform\Core\Serializer\ItemNormalizer

    private function updateObjectToPopulate(array $data, array &$context)
    {
        try {
            $context[self::OBJECT_TO_POPULATE] = $this->iriConverter->getItemFromIri((string) $data['id'], $context + ['fetch_data' => true]);
        } catch (InvalidArgumentException $e) {
            if(!isset($context['resource_class'])){
                return;
            }
            //...
        }
    }

[dunglas]

Fixed by #2326