Annotation to indicate the type of a variable
Static analysis tools are invaluable for catching errors and improving code quality. However, they sometimes struggle to infer the type of a variable, especially in complex scenarios. This can lead to false positives or missed errors. In this post, we'll explore how to use annotations to explicitly tell Intelephense (and other similar tools) the type of a variable in PHP, ensuring accurate static analysis.
The Problem: Intelephense's Limitations
Let's say we have a PHP controller method where we retrieve a user object:
class TestAuthController extends AbstractController
{
#[Route('/api/test/auth', name: 'api_test_auth')]
public function testAuth(): Response
{
$user = $this->getUser();
if ($user) {
return $this->json(
[
'id' => $user->getId(),
'username' => $user->getUserIdentifier(),
'name' => $user->getFirstName() . ' ' . $user->getLastName(),
'roles' => $user->getRoles()
]);
}
return $this->json(['message' => 'Not authenticated'], 401);
}
}
Without knowing the type of "$user", Intelephense might flag "getId()", "getFirstName()", and "getLastName()" as unidentified methods, even if they exist on the actual "User" object. This is because the static analyzer can't definitively determine the type of "$user" based solely on the code.
The Solution: The "@var" Annotation
PHP's "@var" annotation provides a way to explicitly specify the type of a variable. This helps static analysis tools understand the code's intent and perform more accurate analysis. Since our "getUser()" method might return "null", we'll use a union type:
namespace App\Controller;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
class TestAuthController extends AbstractController
{
#[Route('/api/test/auth', name: 'api_test_auth')]
public function testAuth(): Response
{
/** @var App\Entity\User|null $user */
$user = $this->getUser();
if ($user) {
return $this->json(
[
'id' => $user->getId(),
'username' => $user->getUserIdentifier(),
'name' => $user->getFirstName() . ' ' . $user->getLastName(),
'roles' => $user->getRoles()
]);
}
return $this->json(['message' => 'Not authenticated'], 401);
}
}
The code:/** @var App\Entity\User|null $user */
annotation tells Intelephense that "$use" is either an instance of "App\Entity\User" or "null".
Now, Intelephense will correctly recognize the methods called on "$user" within the "if" block, eliminating the false positives.
By using "@var" annotations strategically, you can significantly improve the accuracy of your static analysis and catch potential errors before runtime.
