I cannot reproduce this problem on Symfony 2.8 😋 Can you fork the symfony standard edition and apply the minimal changes to reproduce this issue?

@dmaicher 2.8: https://github.com/swordbeta/symfony-standard/commit/32e300b108ba476f3daed2efee7852d940546df8
master: https://github.com/swordbeta/symfony-standard/commit/a9da9e3d81c40bb8cf3db8218508d4e3664ed204

Tested on 3 different machines with 7.1.3 and 7.1.4

ok thanks 👍 I think the difference to my tests was that I tested it behind a firewall 😋

Seems weird indeed the behaviour.

This works:

    /**
     * @Route("/", name="homepage")
     */
    public function indexAction()
    {
        $this->get('session')->set('test', 'test');
        return new Response('All good');
    }

And this also:

    /**
     * @Route("/", name="homepage")
     */
    public function indexAction()
    {
        $this->get('session')->set('test', 'test');
        $this->get('session')->save();
        $this->get('session')->start();
        return new Response('All good');
    }

@dmaicher weird that the first one works, isn't save always called at the end? I guess I could just remove the save call for now

Looks like this is some how expected https://github.com/symfony/symfony/blob/master/src/Symfony/Component/HttpFoundation/Session/Storage/MockFileSessionStorage.php#L104, maybe a documentation issue?

You shouldn't be calling save() yourself as the framework already takes care of it. If save() is called twice, the second time it will throw an exception (which is the reason why you're getting different output in your test).

This looks like a bug. The NativeSessionStorage does not throw an exception when saving twice. A session_write_close on an inactive session is just ignored and does nothing. The mocked session must have the same behavior otherwise the two implementations are inconsistent.

Well, the logic was deliberately introduced in #6362

Investigating this again as part of the EUFOSSA hackathon.

I cannot reproduce this anymore on Symfony 3.4+.

Also with recent changes in Session we will not call save on the storage if the session is not started (anymore):

https://github.com/symfony/symfony/blob/4.2/src/Symfony/Component/HttpFoundation/Session/Session.php#L196

So I think we can close this @jakzal @Tobion ?

I still think it should not throw an exception in