minor #24740 [Form] Nullable FormInterface::getPropertyPath() (vudaltsov)
minor #24740 [Form] Nullable FormInterface::getPropertyPath() (vudaltsov)

This PR was merged into the 2.7 branch.

Discussion
----------

[Form] Nullable FormInterface::getPropertyPath()

| Q             | A
| ------------- | ---
| Branch?       | 4.0
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #24560
| License       | MIT
| Doc PR        |

`Symfony\Component\Form\Form::getPropertyPath()` returns `null` when the form has an empty name. It allows for unprefixed children.

```php
<?php

namespace App\Controller;

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Template;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\Form\Extension\Core\Type\TextType;

class IndexController extends AbstractController
{
    /**
     * @Route(name="index")
     * @Template()
     */
    public function indexAction()
    {
        $form = $this->get('form.factory')
            ->createNamedBuilder('')
            ->add('text', TextType::class)
            ->getForm();

        return [
            'form' => $form->createView(),
        ];
    }
}
```

```html
<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Welcome!</title>
    </head>
    <body>
        <form name="" method="post">
            <label for="text">Text</label>
            <input type="text" id="text" name="text">
        </form>
    </body>
</html>
```

But the return type of the `Symfony\Component\Form\FormInterface::getPropertyPath()` is not nullable.

We cannot change the behaviour, obviously. At least it's useful in API controllers.

So I decided to change the doc block of the interface.

Commits
-------

d56632a45f FormInterface::getPropertyPath(): PropertyPathInterface|null

fabpot/symfony,michaelperrin/symfony,jakzal/symfony,joelwurtz/symfony,symfony/symfony,teohhanhui/symfony,mihai-stancu/symfony,SaschaDens/symfony,paradajozsef/symfony,localheinz/symfony,sroze/symfony,jzawadzki/symfony,maidmaid/symfony,jderusse/symfony,MatTheCat/symfony,pyrech/symfony,mnapoli/symfony,ajgarlag/symfony,Soullivaneuh/symfony,zorn-v/symfony,paradajozsef/symfony,jderusse/symfony,pyrech/symfony,smatyas/symfony,bendavies/symfony,garak/symfony,hhamon/symfony,andrerom/symfony,e-moe/symfony,zorn-v/symfony,jderusse/symfony,deguif/symfony,michaelperrin/symfony,zorn-v/symfony,1ed/symfony,andreia/symfony,sroze/symfony,gencer/symfony,e-moe/symfony,smatyas/symfony,damienalexandre/symfony,SpacePossum/symfony,c960657/symfony,Tobion/symfony,nasimnabavi/symfony,Simperfit/symfony,nasimnabavi/symfony,ogizanagi/symfony,OndraM/symfony,SpacePossum/symfony,c960657/symfony,HeahDude/symfony,ro0NL/symfony,ragboyjr/symfony,zerkms/symfony,andreia/symfony,phramz/symfony,SpacePossum/symfony,pamil/symfony,ajgarlag/symfony,Deamon/symfony,OndraM/symfony,mpdude/symfony,symfony/symfony,Koc/symfony,OndraM/symfony,jakzal/symfony,kbond/symfony,shieldo/symfony,Simperfit/symfony,nicolas-grekas/symfony,apetitpa/symfony,alekitto/symfony,MatTheCat/symfony,yceruto/symfony,yceruto/symfony,paradajozsef/symfony,nasimnabavi/symfony,docteurklein/symfony,andrerom/symfony,ro0NL/symfony,symfony/symfony,apetitpa/symfony,Nyholm/symfony,Deamon/symfony,lyrixx/symfony,nicolas-grekas/symfony,1ed/symfony,andrerom/symfony,WhiteEagle88/symfony,alekitto/symfony,mihai-stancu/symfony,nicolas-grekas/symfony,andrerom/symfony,Deamon/symfony,bendavies/symfony,fabpot/symfony,mvhirsch/symfony,tgalopin/symfony,voronkovich/symfony,hacfi/symfony,weaverryan/symfony,hacfi/symfony,mweimerskirch/symfony,dunglas/symfony,zorn-v/symfony,dmaicher/symfony,Pierstoval/symfony,Soullivaneuh/symfony,inso/symfony,mihai-stancu/symfony,alekitto/symfony,d-ph/symfony,OskarStark/symfony,xabbuh/symfony,pierredup/symfony,curry684/symfony,localheinz/symfony,Slamdunk/symfony,iltar/symfony,dunglas/symfony,oleg-andreyev/symfony,c960657/symfony,oleg-andreyev/symfony,shieldo/symfony,HeahDude/symfony,OskarStark/symfony,localheinz/symfony,joelwurtz/symfony,ro0NL/symfony,1ed/symfony,SpacePossum/symfony,Koc/symfony,Einenlum/symfony,Soullivaneuh/symfony,Einenlum/symfony,bendavies/symfony,pierredup/symfony,jvasseur/symfony,gencer/symfony,romaricdrigon/symfony,kbond/symfony,andreia/symfony,yceruto/symfony,damienalexandre/symfony,nicolas-grekas/symfony,ogizanagi/symfony,xabbuh/symfony,mweimerskirch/symfony,mpdude/symfony,OskarStark/symfony,zerkms/symfony,d-ph/symfony,oleg-andreyev/symfony,vincentaubert/symfony,iltar/symfony,lyrixx/symfony,hhamon/symfony,curry684/symfony,inso/symfony,sgehrig/symfony,apetitpa/symfony,romaricdrigon/symfony,phramz/symfony,jzawadzki/symfony,sgehrig/symfony,fabpot/symfony,SaschaDens/symfony,Koc/symfony,tgalopin/symfony,arjenm/symfony,Soullivaneuh/symfony,ragboyjr/symfony,e-moe/symfony,dmaicher/symfony,docteurklein/symfony,derrabus/symfony,tgalopin/symfony,curry684/symfony,phramz/symfony,weaverryan/symfony,mpdude/symfony,localheinz/symfony,maidmaid/symfony,zcodes/symfony,Tobion/symfony,docteurklein/symfony,lstrojny/symfony,stof/symfony,hhamon/symfony,chalasr/symfony,OndraM/symfony,mpdude/symfony,WhiteEagle88/symfony,derrabus/symfony,hacfi/symfony,dmaicher/symfony,Einenlum/symfony,MatTheCat/symfony,teohhanhui/symfony,shieldo/symfony,Pierstoval/symfony,shieldo/symfony,xabbuh/symfony,joelwurtz/symfony,pierredup/symfony,gonzalovilaseca/symfony,kbond/symfony,Pierstoval/symfony,vincentaubert/symfony,Einenlum/symfony,Nyholm/symfony,gonzalovilaseca/symfony,stof/symfony,arjenm/symfony,garak/symfony,maidmaid/symfony,smatyas/symfony,jderusse/symfony,ragboyjr/symfony,mnapoli/symfony,Tobion/symfony,zcodes/symfony,garak/symfony,zerkms/symfony,docteurklein/symfony,OndraM/symfony,arjenm/symfony,fabpot/symfony,damienalexandre/symfony,pyrech/symfony,smatyas/symfony,frankdejonge/symfony,d-ph/symfony,jvasseur/symfony,gnat42/symfony,inso/symfony,Slamdunk/symfony,Tobion/symfony,pierredup/symfony,gonzalovilaseca/symfony,phramz/symfony,stof/symfony,HeahDude/symfony,mnapoli/symfony,OskarStark/symfony,gimler/symfony,mnapoli/symfony,sgehrig/symfony,jean-gui/symfony,vincentaubert/symfony,oleg-andreyev/symfony,nasimnabavi/symfony,garak/symfony,maidmaid/symfony,michaelperrin/symfony,mvhirsch/symfony,deguif/symfony,romaricdrigon/symfony,dmaicher/symfony,jean-gui/symfony,gimler/symfony,weaverryan/symfony,docteurklein/symfony,Taluu/symfony,zcodes/symfony,pamil/symfony,gimler/symfony,derrabus/symfony,Nyholm/symfony,pamil/symfony,mnapoli/symfony,mweimerskirch/symfony,WhiteEagle88/symfony,c960657/symfony,frankdejonge/symfony,Pierstoval/symfony,jean-gui/symfony,frankdejonge/symfony,Simperfit/symfony,sroze/symfony,Taluu/symfony,1ed/symfony,gonzalovilaseca/symfony,michaelperrin/symfony,ajgarlag/symfony,jzawadzki/symfony,xabbuh/symfony,ogizanagi/symfony,Koc/symfony,pamil/symfony,mihai-stancu/symfony,Slamdunk/symfony,gencer/symfony,Soullivaneuh/symfony,mvhirsch/symfony,teohhanhui/symfony,deguif/symfony,tucksaun/symfony,HeahDude/symfony,tucksaun/symfony,sgehrig/symfony,gnat42/symfony,apetitpa/symfony,voronkovich/symfony,hhamon/symfony,lstrojny/symfony,e-moe/symfony,chalasr/symfony,voronkovich/symfony,jvasseur/symfony,weaverryan/symfony,lyrixx/symfony,Taluu/symfony,Slamdunk/symfony,tgalopin/symfony,chalasr/symfony,inso/symfony,jean-gui/symfony,sroze/symfony,mihai-stancu/symfony,inso/symfony,ro0NL/symfony,kbond/symfony,Taluu/symfony,bendavies/symfony,damienalexandre/symfony,paradajozsef/symfony,mvhirsch/symfony,romaricdrigon/symfony,SaschaDens/symfony,tucksaun/symfony,lyrixx/symfony,gimler/symfony,zerkms/symfony,jakzal/symfony,d-ph/symfony,jvasseur/symfony,ragboyjr/symfony,lstrojny/symfony,ogizanagi/symfony,mvhirsch/symfony,curry684/symfony,stof/symfony,zcodes/symfony,chalasr/symfony,SpacePossum/symfony,Deamon/symfony,yceruto/symfony,andreia/symfony,tucksaun/symfony,symfony/symfony,Simperfit/symfony,Nyholm/symfony,SaschaDens/symfony,jakzal/symfony,pyrech/symfony,MatTheCat/symfony,mweimerskirch/symfony,vincentaubert/symfony,SaschaDens/symfony,voronkovich/symfony,dunglas/symfony,iltar/symfony,Simperfit/symfony,Deamon/symfony,alekitto/symfony,smatyas/symfony,gnat42/symfony,gnat42/symfony,iltar/symfony,arjenm/symfony,joelwurtz/symfony,derrabus/symfony,teohhanhui/symfony,ajgarlag/symfony,mweimerskirch/symfony,deguif/symfony,frankdejonge/symfony