Add “instances” argument to BaseModelFomSet.__init__()

[aki33524]

There are two reasons.

First, as you know, ModelForm can accept instance as keyword arguments.
I think that BaseModelFormSet should follow this. Current BaseModelFormSet support save(commit=False), which returns “instances”. But now, we cannot use it without INSERT in DataBase..

Second, Current BaseModelFormSet accepts “queryset” as keyword argument.
“queryset” can convert to “instances”, but “instances” cannot convert to “queryset”. I think that BaseModelFormSet should accept not “queryset” but “instances”.

For downward compatible, it would be difficult that “instances” replace with “queryset”. So I suggest adding “instances” argument to BaseModelFormSet init.

[Collin Anderson]

Are you just proposing a name change, or would it function different than how queryset currently functions?

[aki33524]

Replying to collinanderson:

Are you just proposing a name change, or would it function different than how queryset currently functions?

A 'QuerySet' represents a collection of objects from your database.

AuthorFormSet = modelformset_factory(Author, max_num=1)
formset = AuthorFormSet(queryset=Author.objects.filter(name__startswith='O'))

On the other hand, 'instances' which I propose, DON'T NEED to be INSERTed in database.

AuthorFormSet = modelformset_factory(Author, max_num=1)
instances = [Author() for i in range(10)]
formset = AuthorFormSet(instances=instances)

It follows ModelForm.

a = Author()
f = AuthorForm(request.POST, instance=a)

For example, I tryed to store 'instances', which is returned by formset.save(commit=False), in session. In other words, instances don't be INSERTed. Then I want to INSERT these instances in database at last.This application can modify these instances, current BaseModelFormSet cannot do it.

[Tim Graham]

I think your use case could be solved by using ​initial data and ​an empty QuerySet. I don't think adding more complexity to formsets is the answer, but if I've missing something please reopen with more details. Thanks.