In 5a56b23 you can see app.flashes returns an empty array if the session hasn't started. Reading http://symfony.com/doc/current/session/avoid_session_start.html this seems really weird to me; this means I have to add app.session.start() after checking forapp.request.hasPreviousSession if I want to make sure any flash is displayed.

Is this really wanted? If we must check for app.request.hasPreviousSession then reading flashes could start the session.