[newforms-admin] Initial form data passed from request.GET isn't handled correctly by the admin

[Matthias Pronk <django@…>]

The admin interface used to pass initial data from the URL to the forms, so calling for example:

/admin/auth/user/add/?username=foo

Would result in the "username" field to be prefilled with "foo".

This is broken in recent newforms-admin because the MultiValueDict (QueryDict) is used to extend an ordinary dict in django.newforms.forms.

The way to resolve this problem is to "flatten" the MultiValueDict to an ordinary dictionary, before passing it to the ModelForm.

Thanks to brosner on #django for the help! (basically fixing it ;)

[Matthias Pronk <django@…>]

Instead of solving this in the Admin, it would be better to fix it in the ModelForm code, see #6939

[Brian Rosner]

Reopening due to the note in #6314.

[Brian Rosner]

(In [7434]) newforms-admin: Fixed #6938 -- request.GET is now coerced into a dict before being passed as initial data in ModelAdmin.add_view. Thanks Matthias Pronk.