"Session has not been set" when loading a form in ajax wrapper in D10.3 or higher

Not sure if correct way to fix, but this patch works for me

@victonator I've not encountered the issue with the wrapper so far on 10.3, but I don't think I have forms that load through AJAX wrapper.

If I understand the issue correctly the form is what requires a session and not ajax wrapper? If so, the session should probably be initiated somewhere in the form and not in AJAX wrapper. Correct me if I'm wrong though :)

Hi @mauro_
In AjaxWrapperController.php:183 a new request is created and later on gets pushed in the requestStack.
FormBuilder.php requires a session from the currentRequest which is now the new request without a session from ajax_wrapper.
Adding the session from the mainRequest to the currentRequest (or something like that) is not something I should have to do when building my form in my opinion :) .
This should be handled in the module in some way, like in the attached patch.

We encountered the same problem on one of our projects.