Symfony Doctrine Uplodable with relation

config.yml

# app/config/config.yml

stof_doctrine_extensions:
    default_locale: "%locale%"
    uploadable:
        # Default file path: This is one of the three ways you can configure the path for the Uploadable extension
        default_file_path:       "%kernel.root_dir%/../web/upload"
        # Mime type guesser class: Optional. By default, we provide an adapter for the one present in the HttpFoundation component of Symfony
        mime_type_guesser_class: Stof\DoctrineExtensionsBundle\Uploadable\MimeTypeGuesserAdapter
        # Default file info class implementing FileInfoInterface: Optional. By default we provide a class which is prepared to receive an UploadedFile instance.
        default_file_info_class: Stof\DoctrineExtensionsBundle\Uploadable\UploadedFileInfo
    orm:
        default:
            uploadable: true # uploadable: ~ seems not work 

Document.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Gedmo\Mapping\Annotation as Gedmo;

/**
 * Document
 *
 * @ORM\Table(name="document")
 * @ORM\Entity()
 *
 * @Gedmo\Uploadable(
 *     filenameGenerator="SHA1",
 *     allowOverwrite=true,
 *     appendNumber=true
 * )
 */
class Document
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * FQFN ( /path/to/file.ext )
     *
     * @var string
     *
     * @ORM\Column(name="path", type="string", length=255)
     * @Gedmo\UploadableFilePath
     */
    private $path;

    /**
     * Name + Extension ( file.ext )
     *
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255)
     * @Gedmo\UploadableFileName
     */
    private $name;

    /**
     * Mime Type
     *
     * @var string
     *
     * @ORM\Column(name="mime", type="string", length=255)
     * @Gedmo\UploadableFileMimeType
     */
    private $mime;

    /**
     * Size in bytes
     *
     * @var string
     *
     * @ORM\Column(name="size", type="decimal", precision=10, scale=2)
     * @Gedmo\UploadableFileSize
     */
    private $size;

    // ...
}

DocumentType.php

<?php

namespace AppBundle\Form;

// ...
use Symfony\Component\Form\CallbackTransformer;
use Symfony\Component\HttpFoundation\File\File;


class DocumentType extends AbstractType
{
    /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            // ...
            ->add('path', FileType::class)
            ->get('path')->addModelTransformer(new CallbackTransformer(
                    function ($string) {
                        if (!$string){
                            return;
                        }

                        return new File($string);
                    },
                    function (File $file = null) {
                        return $file;
                    }
                ))
            ;
        ;
    }

    // ...
}

User.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * User
 *
 * @ORM\Table(name="fos_user")
 * @ORM\Entity()
 */
 
class User
{
    // ...
    
    /**
     * @ORM\OneToOne(targetEntity="Document", cascade={"persist", "remove"})
     * @ORM\JoinColumn(name="document_id", referencedColumnName="id", nullable=true)
     */
    private $avatar;
    
    // ...
    
    /**
     * @param \AppBundle\Entity\Document $avatar
     *
     * @return User
     */
    public function setAvatar(\AppBundle\Entity\Document $avatar = null)
    {
        $this->avatar = $avatar;

        return $this;
    }

    // ...
}

UserController.php

<?php

namespace AppBundle\Controller;

// ...

class UserController extends Controller
{

    public function newAction(Request $request)
    {
        // ...
        
        $em = $this->getDoctrine()->getManager();
        $em->persist($user);
    
        $uploadableManager = $this->get('stof_doctrine_extensions.uploadable.manager');
        // Here, "getAvatar" returns the "UploadedFile" instance that the form bound in your $avatar property
        $uploadableManager->markEntityToUpload(
            $user->getAvatar(),
            $user->getAvatar()->getPath()
        );
    
        $em->flush();
    
        // ...
        
    }
    
    // same for editAction()
}

UserType.php

<?php

namespace AppBundle\Form;

// ...
use AppBundle\Form\DocumentType;

class UserType extends AbstractType
{
    /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            // ...
            ->add('avatar', DocumentType::class)
        ;
    }

Interesting. I have this same setup, but I'm getting a type mismatch error "Expected value of type "AuditBundle\Entity\File" for association field "AuditBundle\Entity\AuditEvidence#$file", got "Symfony\Component\HttpFoundation\File\UploadedFile" instead." Somewhere there doesn't seem to be a transformer being called??