Formset validation refactoring and valid_forms property of fieldsets

[Petr Marhoun <petr.marhoun@…>]

This series of patch solves two problems:

• Formsets validation is spread in four different methods so it is very difficult to comprehend the code and to solve possible problems.
• There is no method which gives valid forms in all situation - especially, valid formset can contain invalid form if this form should be deleted. So this ticket adds new property valid_forms which returns all valid (and filled) forms, possible ordered.

There is wiki page and discussion in django-developers:

• ​http://code.djangoproject.com/wiki/ImprovementsForDjangoForms#BetterAPIforformsets
• ​http://groups.google.com/group/django-developers/browse_thread/thread/37e1e8b8313c38de

[Petr Marhoun <petr.marhoun@…>]

The first patch (01-formset-refactoring.diff) contains changes of code. The second patch (02-formset-refactoring-cleaned-data-tests.diff) shows that cleaned_data as attribute of formsets or forms in formsets are problematic (this patch could be applied to trunk to expose the situation). The third patch (03-formset-refactoring-valid-forms-tests.diff) contains tests for new property valid_forms.

[Russell Keith-Magee]

Marking accepted on the basis of the discussion on django-dev -- on principle, this sounds like a reasonable idea, but it needs a *very* detailed review. Widespread changes of this nature make me *very* nervous about backwards compatibility issues. The test coverage you have provided is a very good start, but I don't have complete confidence that the existing test suite covers all possible backwards compatibility issues.

Speaking of which -- the tests need to be updated to unittests; the patches don't currently apply cleanly.

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.