This is wrong, as Session is an implementation of SessionInterface, also because you can use a mocked SessionInterface object.

👎 for reasonons @henrikbjorn mentioned.

What about add getFlashBag() method to the SessionInterface?

   /**
    * Gets the flashbag interface.
    *
    * @return FlashBagInterface
    */
    public function getFlashBag();

why you closed this? what was your need? autocompletion? could you please explain?

@cordoval Yes, I want to use auto complete for getFlashBag() method, calling from $this->get('session') session service in my controllers

@bocharsky-bw the right way is to typehint your controller action with Request and use $request->getSession() instead, Request and Session should not be accessed through the container.

it is not a good reason, i just advise to type hint it with a docblock in situ

/** @var $x \FQCN_HERE */
$x = $this->get('session');
$x->

You can also do the same with the request_stack

considering moving a method to an interface though for the right reason it is I believe considered in the BC promise documentation in Symfony docu.

@cordoval Yes, thanks! I think docblock is the good solution in this case.

@henrikbjorn But there isn't auto complete when I try to get access to the getFlashBag() method from $request->getSession() object

That is because getFlashBag() is not part of the SessionInterface, the reason for this is that the flash handling was redone and to keep BC new methods cannot be added to the interface before 3.0

@henrikbjorn is adding a new method to the interface always a break? I thought renaming methods other name could still keep BC. Please correct me if I am wrong

Its a BC because the previous versions released does not have that method, so if i implemented the interface in an old version and the interface changes, my implementation will be broken.

@cordoval Adding concrete methods is BC. Adding abstract methods is a BC rbeak as it forces child classes to be updated to implement them. Methods of an interface are always abstract

I see, thanks for the explanation @stof @henrikbjorn