Django Rest Framework Nested Serializer required=False error

Question

Ok, so Kevin Browns comment is correct. I needed to add allow_null=True.

class SerializerA(serializers.Serializer):
    details = DetailsSerializer(required=False, allow_null=True)

The reason for this is that having required=False allows the field details to be absent from the data when constructing the serializer.

e.g.
s = SerializerA(data={})

whereas allow_null permits the the param to be specified but be null.

e.g.
s = SerializerA(data={'details': None})

This opens up another issue with DRF Browsable API, but i’ll ask that in a different question.