Symfony version(s) affected

6.1.0

Description

#44695 added @return TestContainer to KernelTestCase::getContainer(). However, TestContainer is marked @internal, which makes any calls static::getContainer()->get(MyService::class) invalid, for example to Psalm (and possibly also to IDEs):

ERROR: InternalMethod - MyTest.php:16:49 - The method Symfony\Bundle\FrameworkBundle\Test\TestContainer::get is internal to Symfony but called from MyTest (see https://psalm.dev/175)
        $this->client = static::getContainer()->get(MyService::class);

How to reproduce

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

final class MyTest extends KernelTestCase
{
    public function test_container_get(): void
    {
        static::getContainer()->get(MyService::class);
    }
}

Possible Solution

Remove @internal from TestContainer.

Additional Context

No response