Symfony version(s) affected

6.4

Description

When validating file uploads using the FileType with multiple => true, an UnexpectedValueException is thrown from Symfony\Component\Validator\Constraints\FileValidator at line 120.

Current Behavior:
The exception occurs in FileValidator at this condition:

if (!\is_scalar($value) && !$value instanceof FileObject && !$value instanceof \Stringable) {
    throw new UnexpectedValueException($value, 'string');
}

Expected Behavior:
The validator should properly handle multiple file uploads without throwing an exception. When multiple => true is set, the input should be processed as an array of files rather than a single value.

How to reproduce

Code Example:

$builder->add('files', FileType::class, [
    'constraints' => [
        new File([
            'maxSize' => '1024k',
            'extensions' => ['jpg','jpeg','png']
        ], binaryFormat: true)
    ],
    'required' => false,
    'multiple' => true
]);

Possible Solution

No response

Additional Context

This appears to be incorrect behavior specifically when validating file inputs with the multiple option enabled. The validator should account for array values when dealing with multiple file uploads.