PHP late static binding doesn't work correctly

Question

While coding and using late static binding in PHP I found some strange behaviour. A child object created with static() in its parent class can access the private methods of its parent.

Here's an example:

class Attachment
{
  public static function createFromFile($file)
  {
    $attachment = new static();
    echo get_class($attachment) . PHP_EOL;
    $attachment->loadFromFile($file);
  }

  private function loadFromFile($file)
  {
    echo 'attachment';
  }
}

class PictureAttachment extends Attachment
{
  //...
}

PictureAttachment::createFromFile('example.txt');

Output:

PictureAttachment
attachment

Is this a correct behaviour?

Answer 1

Yes, this is correct. The class that is calling the private method is the same that is declaring it. It doesn't matter that it may or may not instantiate a child class. You just can't have any code in the child class calling the private method of the parent.

In other words:

class Foo {

    protected function bar() {
        $this->baz();
    }

    private function baz() { }

}

class Bar extends Foo {

    protected function bar() {
        parent::bar();   // <-- works
        parent::baz();   // <-- doesn't work
    }

}