Modify Nested field to handle the combination of many=True and allow_… #1498
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That is existing behavior and orthogonal to #1497. |
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| def test_nested_multiple_allow_none_deserialize_none_to_none(self): | ||
| field = fields.Nested(Schema(), allow_none=True, many=True) | ||
| assert field.deserialize([None, {}]) == [None, {}] |
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The allow_none argument on Nested applies to the Nested container, not its children. Depending on many this is either a List, or a pass through container.
https://marshmallow.readthedocs.io/en/stable/api_reference.html#marshmallow.fields.Nested
Use List(Nested(allow_none)) instead. #779 is an RFC that is amassing reasons Nested(many) should be deprecated. I will add this to the list.
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Oh, yes, you're absolutely right about allow_none for nested attributes. So I guess we only need to revert the optimisation on lists of nested attributes. Is this merge request still relevant then ? Sorry for the delay, I could not find the time to follow up on the related issue but I will I'm the coming days. |
Fix for #1497
Hi,
I tried to fix the issue by modifying
Schemaas suggested in the issue discussion but it would fail to detect validation errors when[None]is passed to aNested(many=True, allow_none=False)field as the schema is not aware ofallow_none.Instead, I made the
Nestedfield check when (de-)serializing ifmanyandallow_noneare both set toTrue. in that case, we simply pass the non-Nonevalues to the underlying schema then insertNonevalues back in the resulting list.