Commits-------5ae76f1 [HttpFoundation] Update documentation.910b5c7 [HttpFoudation] CS, more tests and some optimization.b0466e8 [HttpFoundation] Refactored BC Session class methods.84c2e3c [HttpFoundation] Allow flash messages to have multiple messages per type.Discussion----------[2.1][HttpFoundation] Multiple session flash messagesBug fix: noFeature addition: yesBackwards compatibility break: yes, but this already happened in#2583.  BC `Session` methods remain unbroken.Symfony2 tests pass: yesFixes the following tickets:#1863References the following tickets:#2714,#2753,#2510,#2543,#2853Todo: -This PR alters flash messages so that it is possible to store more than one message per flash type using the `add()` method or by passing an array of messages to `set()`.__NOTES ABOUT BC__This PR maintains BC behaviour with the `Session` class in that the old Symfony 2.0 methods will continue to work as before.---------------------------------------------------------------------------by drak at 2012-02-13T06:28:33ZI think this is ready for review@fabpot@lsmith77---------------------------------------------------------------------------by lsmith77 at 2012-02-14T19:30:39Zthe FlashBag vs. AutoExpireFlashBag behavior and setup difference should probably also be explained in the upgrading log---------------------------------------------------------------------------by drak at 2012-02-15T04:43:14Z@lsmith77 Those differences are explained already in the changelog * Added `FlashBag`. Flashes expire when retrieved by `get()` or `all()`.   This makes the implementation ESI compatible. * Added `AutoExpireFlashBag` (default) to replicate Symfony 2.0.x auto expire behaviour of messages auto expiring   after one page page load.  Messages must be retrived by `get()` or `all()`.---------------------------------------------------------------------------by Crell at 2012-02-19T17:35:34ZDrak asked me to weigh in here with use cases.  Drupal currently has a similar session-stored-messaging system in place that I'd like to be able to replace with Flash messages.  We frequently have multiple messages within a single request, however, so this change is critical to our being able to do so.For instance, when saving an article in Drupal there is, by default, a "yay, you saved an article!" type message that gets displayed.  If you also have the site configured to send email when a post is updated, you may see a "email notifications sent" message (depending on your access level).  If you have a Solr server setup for search, and you're in debug mode, there will also be a "record ID X added to Solr, it should update in 2 minutes" message.  And if there's a bug somewhere, you'll also get, as an error message rather than notice message, a "Oops, E_NOTICE on line 54" message.Form validation is another case.  If you have multiple errors in a single form, we prefer to list all of them.  So if you screw up 4 times on a form, you may get 4 different error messages showing what you screwed up so you can fix it in one go instead of several.Now sure, one could emulate that by building a multi-message layer on top of single-layer messages, but, really, why?  "One is a special case of many", and there are many many cases where you'll want to post multiple messages.  Like, most of Drupal. :-)---------------------------------------------------------------------------by lsmith77 at 2012-03-06T20:55:51Z@fabpot is there any information you still need before merging this? do you want more discussion in which case you might want to take this to the mailing list ..---------------------------------------------------------------------------by drak at 2012-03-08T18:54:13ZAnother plus for this PR is that it requires no extra lines of code in templates etc to display the flashes, seehttps://github.com/symfony/symfony/pull/3267/files#diff-1---------------------------------------------------------------------------by drak at 2012-03-15T06:38:21ZRebased against current `master`, should be mergeable again..---------------------------------------------------------------------------by evillemez at 2012-03-17T03:08:41Z+1 to this, I have an extended version of HttpFoundation just for this... would love to get rid of it.