Property $app with generic class Slim\App does not specify its types: TContainerInterface

[j0k3r]

Following this PR #3322, PHPStan is yelling on one of our project.

The error is:

Property Tests\OurProject\BaseTestCase::$app with generic class Slim\App does not specify its types: TContainerInterface

Here is the code:

<?php

namespace Tests\OurProject;

use PHPUnit\Framework\TestCase;

class BaseTestCase extends TestCase
{
    /** @var \Slim\App */
    protected $app;

    protected function setUpApp(bool $mockedClient = false): void
    {
        $this->app = require __DIR__ . '/../src/App.php';

PHPStan throw that error on the line protected $app;.
What type or change I need to apply to resolve it?

Poke @limarkxx

[akrabat]

As App has a getContainer(): ?ContainerInterface method, the generic doc block enables you to specify what type is actually returned when this method is called. i.e. if you are using PHPDI and write:

$container = $this->app->getContainer();
$entries = $container->getKnownEntryNames();

PHPStan has no way of knowing that $container is an instance of PHPDI which has a getKnownEntryNames() method and so will complain.

To tell PHPStan this we change: /** @var \Slim\App $app */ to /** @var \Slim\App<DI\Container> $app */ and now PHPStan knows this.

If you want to use just PSR ContainerInterface methods, then you hint as /** @var \Slim\App<\Psr\Container\ContainerInterface> $app */

If you are not using a container at all, then hint with: /** @var \Slim\App<null> $app */

[j0k3r]

Awesome, thanks for that great explanation.
I'm not so familiar with template & generics.