Reviewing PHP code in Laravel framework

Have a look here https://github.com/laravel/framework/blob/7.x/src/Illuminate/Auth/GenericUser.php#L32

and

here https://laravel.com/api/7.x/search.html?search=getAuthIdentifier

The api points to where the code is.

It uses a function to return the name of the column to be used, and then returns its value.

so if the function getAuthIdentifierName() returns the string 'username' then the function you have highlighted is the same as writing

    public function getAuthIdentifier()
    {
        return $this->username;
    }

Its done this way because it is using a trait to include code in your app\Http\Controllers\Auth\LoginController.

If you wanted to use a different database column for the user identifier then you can create a function in your login controller like;

    public function getAuthIdentifierName()
    {
        return 'email';
    }

This method will override the one in the trait and then getAuthIdentifier will return the contents of the email column not the username column

You would not normally use this level of abstraction in your code, its used here to make the framework extensible.

Thank you guys for the replies. :)