How to properly inject Yii2 class dependencies?

Question

Yii

Help me understand where I'm wrong. It seems like I'm doing everything right!
We need to extend the functionality of the class:

use custom\class\Finder;
class BaseLoginForm extends Model
{
    /** @var Finder */
    protected $finder;

    /**
     * @param Finder $finder
     * @param array  $config
     */
    public function __construct(Finder $finder, $config = [])
    {
        $this->finder = $finder;
        parent::__construct($config);
    }
}

I do like this:

use own\class\Finder;
class LoginForm extends BaseLoginForm
{
    /** @var Finder */
    protected $finder;

    /**
     * @param Finder $finder
     * @param array  $config
     */
    public function __construct(Finder $finder, $config = [])
    {
        $this->finder = $finder;
        parent::__construct($finder, $config);
        
    }
}

The problem is that after I do this - $finder = null !
Perhaps Finderthe class needs to be registered somewhere so that it Yiiknows where to inject the dependency ????? Help me to understand !

Answer 1

In the child class, it is not necessary to describe finderthe constructor either, because they are inherited.
Concerning implementation: whence Yii2 should take a class Finder?
And in fact, the following code is also an injection:

$finder = new Finder();
$loginForm = new LoginForm($finder);

Or do you not like this option?

Answer 2

Use the built-in dependency container