Readd getter for MetadataFactory in Serialzier

[tgaertner]

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

Re-add getter for MetadataFactory in Serialzier to make it possible again to override metadata types like this:
/** @var \JMS\Serializer\Metadata\PropertyMetadata $itemsMetadata */
$itemsMetadata = $this->serializer->getMetadataFactory()->getMetadataForClass(Content::class)->propertyMetadata['items'];
$itemsMetadata->setType($type);

Expected Result

• This code worked in version 1.x and breaks ins version (2.x) 3.x

Actual Result

• Found no other way to achieve the desired type override.

[scyzoryck]

Hi @tgaertner!
This usage seems to be a bit hacky to override the property types on the Factory level and might impact performance & Could you provide more context what is a use case for you? May I will be better to help you with some better solution :)

[tgaertner]

Well this is some legacy code, I haven't written. The full function looks like this:

/**
     * @param string $embeddedType
     * @return string
     */
    protected function getPagerType(string $embeddedType)
    {
        $type = [
            'name' => 'array',
            'params' => [
                [
                    'name' => $embeddedType,
                    'params' => [],
                ],
            ],

        ];

        // Overrides Configuration: Vendor.Package.Persistence.HATEOAS.Content.yml
        /** @var PropertyMetadata $itemsMetadata */
        $itemsMetadata = $this->serializer->getMetadataFactory()->getMetadataForClass(Content::class)->propertyMetadata['items'];
        $itemsMetadata->setType($type);

        return Pager::class;
    }

This function is only called to override the type for embedded Objects to serialize.