New in Symfony 5.2: PHP 8 attributes

Contributed by Alexander M. Turek in #37474 and #37545

PHP 8 is packed with new interesting features, such as union types, match expressions and constructor property promotion. However, the most sought-after new feature is built-in attributes (also called annotations).

Symfony 5.2 will include support for PHP 8 attributes to define routes and required dependencies. If you already use annotations, the transition will be seamless:

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// BEFORE: annotations defined with Doctrine Annotations library
use Symfony\Component\Routing\Annotation\Route;

class SomeController
{
    /**
     * @Route("/path", name="action")
     */
    public function someAction()
    {
        // ...
    }
}

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// AFTER: annotations defined with PHP 8 attributes
use Symfony\Component\Routing\Annotation\Route;

class SomeController
{
    #[Route('/path', name: 'action')]
    public function someAction()
    {
        // ...
    }
}

The same Route class provides support for Doctrine annotations and PHP attributes, so you don't need to change the class import. The only required change is to update the annotation syntax, which now looks like this: #[ ... ] That's all! Your application is now using native PHP attributes and you can uninstall dependencies like doctrine/annotations if you don't use them elsewhere.

We also added a #[Required] attribute to replace @Required annotation and tell Symfony that a property/method holds a required dependency:

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use Symfony\Contracts\Service\Attribute\Required;

class SomeService
{
    #[Required]
    public Bar $bar;

    #[Required]
    public function setFoo(Foo $foo): void
    {
        // ...
    }
}

PHP is entering a new golden era with the release of PHP 8 and Symfony will be fully-compatible since day one. These attributes are just the beginning and we'll add many more (e.g. for validation) in the coming weeks.