maybe this should be written asIn PHP >=7.2 session_write_close() errors if the session is not started? (single line please)

I was trying to say that this is following the logic of session_write_close in PHP <7.2 - in PHP >=7.2 it returns FALSE.

However I've just read the docs on the interface which say

    /**     * Force the session to be saved and closed.     *     * This method must invoke session_write_close() unless this interface is     * used for a storage object design for unit or functional testing where     * a real PHP session would interfere with testing, in which case     * it should actually persist the session data if required.     *     * @throws \RuntimeException if the session is saved without being started, or if the session     *                           is already closed     */    public function save();

So now I'm not sure what's the right thing to do. What's clear is that is not what \Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage::save() does in 3.4 HEAD.

extra line should be removed

I thought about this approach as well. I hesitated to go this way because of the phpdoc on the interface:

https://github.com/symfony/symfony/blob/master/src/Symfony/Component/HttpFoundation/Session/Storage/SessionStorageInterface.php#L107

Not sure if this would not also be a BC break as someone is relying on this? 😕

Actually it seems thisRuntimeException is only really valid for the mock storages?

see#6362

Edit: but anyway this means if a storage is used that throws an exception on save without being started then this would fail now if the kernel is reset on a non-started (but instantiated) session.

Can we catch that exception in Session::save() and convert it to a warning or deprecation error saying that the storage needs to handle an attempt to save a reset session on its own? The behavior that you describe is what existed prior to this BC break in 3.4.24 for custom storage, prior to that they would have had to handle a reset session on their own anyway.