AppFileValidator.php

// AppFileValidator.php
<?php
declare(strict_types=1);

namespace App\Constraints;

use Symfony\Component\HttpFoundation\File\File;
use Symfony\Component\HttpFoundation\File\UploadedFile;
use Symfony\Component\Mime\MimeTypesInterface;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\Constraints\FileValidator as OriginalFileValidator;
use Symfony\Component\Validator\Exception\UnexpectedTypeException;

class AppFileValidator extends OriginalFileValidator
{
    private MimeTypesInterface $mimeTypes;

    public function __construct(MimeTypesInterface $mimeTypes)
    {
        $this->mimeTypes = $mimeTypes;
    }

    public function validate($value, Constraint $constraint)
    {
        if (!$constraint instanceof AppFile) {
            throw new UnexpectedTypeException($constraint, AppFile::class);
        }

        if (null === $value || '' === $value) {
            return;
        }

        $path = $value instanceof File ? $value->getPathname() : (string)$value;
        $basename = $value instanceof UploadedFile ? $value->getClientOriginalName() : basename($path);
        
        // Here we guess the MIME type with our guesser instead of the default in FileValidator
        $mime = $this->mimeTypes->guessMimeType($path);
        $mimeTypes = (array) $constraint->mimeTypes;

        foreach ($mimeTypes as $mimeType) {
            // ⚠️ If the MIME type is allowed, we set the mimeTypes options to null 
            // in order to avoid a new check with in the FileValidator.
            if ($mimeType === $mime) {
                // reset the mimeTypes constraint
                $constraint->mimeTypes = null;
                // call the FileValidator::validate to validate other constraint
                parent::validate($value, $constraint);

                return;
            }
        }
        
        // Build violations
        $this->context->buildViolation($constraint->mimeTypesMessage)
            ->setParameter('{{ file }}', $this->formatValue($path))
            ->setParameter('{{ type }}', $this->formatValue($mime))
            ->setParameter('{{ types }}', $this->formatValues($mimeTypes))
            ->setParameter('{{ name }}', $this->formatValue($basename))
            ->setCode(AppFile::INVALID_MIME_TYPE_ERROR)
            ->addViolation();
    }
}