Question about usage of allow_create and allow_nested_updates

[orientalperil]

I'm a little confused about the intended way to use allow_create and allow_nested_updates. From what I can understand allow_create means that if there isn't a related record a blank model will be instantiated: https://github.com/shosca/django-rest-witchcraft/blob/f7de54688881510be92d8c5714dd9aaea727e680/rest_witchcraft/serializers.py#L693-L694

There seems to be an inconsistency in how allow_create is used when the nested serializer is a ListSerializer (many=True) versus when it is a BaseSerializer.

As a ListSerializer setting allow_create=True implies allow_nested_updates=True because the related object will be treated the same way: https://github.com/shosca/django-rest-witchcraft/blob/f7de54688881510be92d8c5714dd9aaea727e680/rest_witchcraft/serializers.py#L784-L792

But as a BaseSerializer setting allow_create=True alone will instantiate a blank model but will not update it unless you also set allow_nested_updates=True: https://github.com/shosca/django-rest-witchcraft/blob/f7de54688881510be92d8c5714dd9aaea727e680/rest_witchcraft/serializers.py#L763-L776

Setting allow_create=True alone will save the nested serializer with null for all values.

I can't tell if this difference in behavior is intentional or a bug. Can you clarify about how allow_create is supposed to be used?

[shosca]

Yes, that is correct. allow_create controls what to do when a nested instance is not found and allow_nested_updates controls updating the nested instance. There's an edge case where allow_create can be True with allow_nested_update being False where you can end up being able to create blank nested instances

[orientalperil]

Ok thanks for the confirmation. Is there a reason why the ListSerializer applies allow_create as implying allow_nested_updates? If not I think it could be better to treat ListSerializer and BaseSerializer by the same rules one way or the other. Or at least for a BaseSerializer if you set allow_create but not allow_nested_updates then there could be a warning logged.

[shosca]

I think i see what you're talking about, here: https://github.com/shosca/django-rest-witchcraft/blob/f7de54688881510be92d8c5714dd9aaea727e680/rest_witchcraft/serializers.py#L784-L792

the check on field.child.allow_create on 786 is unnecessary since the above field.child.get_object(item) will already check for allow_create