[Form] Upload file edit example tip is not needed

[nacholibre]

Hi all,
excuse me if I'm not posting this with the right title/tags.

Doc: https://symfony.com/doc/current/controller/upload_file.html
I'm implementing basic file upload, but I find one of the steps unnecessary. I'm talking about this tip:

When creating a form to edit an already persisted item, the file form type still expects a :class:Symfony\\Component\\HttpFoundation\\File\\File instance. As the persisted entity now contains only the relative file path, you first have to concatenate the configured upload path with the stored filename and create a new File class:

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

$product->setBrochureFilename(
    new File($this->getParameter('brochures_directory').'/'.$product->getBrochureFilename())
);

The form type has a field brochure like so:

            ->add('brochure', FileType::class, [
                'label' => 'Brochure (PDF file)',

                // unmapped means that this field is not associated to any entity property
                'mapped' => false,

which is not mapped. So calling:

$product->setBrochureFilename(
    new File($this->getParameter('brochures_directory').'/'.$product->getBrochureFilename())
);

will not do anything related to the FormType, because this field is not in the form type declaration. On the other hand $product->setBrochureFilename() actually expects string. This probably will work because File extends from SplFileInfo which has SplFileInfo::__toString — Returns the path to the file as a string.

This will cause a problem, because SplFileInfo::__toString return the whole path, so after persisting the entity brochureFilename field will be updated with the full path, instead of just the filename.

So basically without the $product->setBrochureFilename() everything works.

[javiereguiluz]

Hi! I'm closing this in favor of #8255, which is a meta-issue which stores all the things related to improving the "File Upload" article. Thanks!