Add possibility to pass MultiValueDict-like objects as a form's data

[Marcin Nowak]

value_from_datadict() of django.forms.widgets.MultipleHiddenInput and django.forms.widgets.SelectMultiple are not based on duck typing but on a strict checking for MultiValueDict class.

Changing implementation to duck typing will make code more flexible and open doors for passing any dict-like and MultiValueDict-like objects as a form's data.

Forms data passed as MultiValueDict class should be slightly faster due to less type checkings, but this is not a goal itself.

The discussion I've started about this improvement is here: ​https://groups.google.com/d/msg/django-developers/v-pk2l0hxHk/Vn-hEjMjAwAJ

I'm attaching a patch proposal.

[Marcin Nowak]

Duck typing proposal for value_from_datadict()

[Tim Graham]

Can you send a pull request with that patch?

[Marcin Nowak]

Yes, here you are - ​https://github.com/django/django/pull/6932
(sorry for late reply)

[Tim Graham <timograham@…>]

In 74bb013:

Fixed #26905 -- Allowed using MultiValueDict-like objects as form data.