Allow formset form widget override for the ORDER field

[Claude Paroz]

It would be handy to be able to override the widget of the added ORDER field of a formset form with can_order=True. The typical use case is to use a HiddenInput to manage the formset ordering in the UI without a visible form field.
At first sight, I think this could be easily doable in the BaseFormSet.add_fields method.

[Hasan Ramezani]

Here is the summary of conversation between me and @claudep on the ​PR :

I did this feature by adding the order_field_widget to formset_factory functions. (now available in the PR)

@claudep suggested managing this by adding a key in widgets property of ModelForm. something like this:

class AuthorForm(ModelForm):
    class Meta:
        model = Author
        fields = ('name', 'title', 'birth_date')
        widgets = {
            'ORDER': HiddenInput(),
        }

It works for ModelForm because we can access the widgets property of ModelForm by : model_form._meta.widgets.
But it is possible to have this feature for formset which generated by the normal forms, because the normal form that inherits from forms.Form has not the widgets property.

So @claudep suggest to first add this feature just for ModelForm.

what is the final decision?

[Hasan Ramezani]

I change my PR and manage the widget based on ORDER key in widgets dictionary. and this feature just works for ModelForm now.

[Carlton Gibson]

On the PR I've suggested a third-option (rather than adding an argument to formset_factory() or using the ModelForm's Meta.widgets ) to have users subclass BaseFormSet in this case and pass that as the formset argument to formset_factory().

This keeps the logic in with the formsets but does not expand the signature of formset_factory(), which is already long enough.

[Hasan Ramezani]

I changed the PR based on your suggestion. please check it and let me know if something else is required.

[Carlton Gibson]

Small tweaks needed then good to go I think.

[Hasan Ramezani]

Requested changes are Done.

[Carlton Gibson]

As per PR, the docs here just need a small amount of work and then this is looking good to go.

[Hasan Ramezani]

Docs fixed as your request.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 5fc5d935:

Fixed #29956 -- Allowed overriding an order field widget in formsets.