Session: fix handling exceptions thrown from SessionHandlerInterface

[fprochazka]

I need to throw exception the SessionHandler.

Currently, when you throw an exception from there, the php thinks the session is started (it doesn't care about the exception) and Nette think it's not started, because the self::$started = TRUE; wasn't executed.

This creates a buggy state, where you cannot call $session->start() again, because it throws Nette\InvalidStateException("session_start(): session is already started")

Failing test is provided.

[fprochazka]

As this is a bugfix of a thing that nobody could have ever used before... Is there any chance this might get into 2.3.0, so I can create a dependency in Kdyby/Redis?

[dg]

Simplification?

        try {
            // session_start returns FALSE on failure only sometimes
            Nette\Utils\Callback::invokeSafe('session_start', array(), function ($message) use (& $e) {
                $e = new Nette\InvalidStateException($message);
            });
        } catch (\Exception $e) {
        }

        Helpers::removeDuplicateCookies();
        if ($e) {
            @session_write_close(); // this is needed
            throw $e;
        }

[fprochazka]

I like that! Updated.

[fprochazka]

Awesome! :)