Regression in 3.5 - AttributeError: type object 'Meta' has no attribute 'model'

[phillipuniverse]

Looks to be caused by #722.

Django - 4.2.11
DRF - 3.14.0

  File "/Users/phillip/Library/Caches/pypoetry/virtualenvs/shipwell-backend-core-cpwchxt0-py3.11/lib/python3.11/site-packages/rest_framework/serializers.py", line 426, in run_validation
    value = self.to_internal_value(data)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/phillip/Library/Caches/pypoetry/virtualenvs/shipwell-backend-core-cpwchxt0-py3.11/lib/python3.11/site-packages/rest_framework/serializers.py", line 481, in to_internal_value
    primitive_value = field.get_value(data)
                      ^^^^^^^^^^^^^^^^^^^^^
  File "/Users/phillip/Library/Caches/pypoetry/virtualenvs/shipwell-backend-core-cpwchxt0-py3.11/lib/python3.11/site-packages/djmoney/contrib/django_rest_framework/fields.py", line 70, in get_value
    model_meta = self.parent.Meta.model._meta
                 ^^^^^^^^^^^^^^^^^^^^^^
AttributeError: type object 'Meta' has no attribute 'model'

I think this is an edge case when using a MoneyField with a Meta and outside of a ModelSerializer. ModelSerializer is the only case where a model is used in DRF.

This should be the reproduction case:

class NonModelSerializer(serializers.Serializer):
    invoice_amount = MoneyField(
        max_digits=constants.DIGIT_SIZE_10,
        decimal_places=constants.DIGIT_SIZE_2,
        required=False,
        allow_null=True,
    )

    class Meta:
        fields = (
            "invoice_amount"
        )

[phillipuniverse]

The fix should be pretty easy by gating both self.parent.Meta and self.parent.Meta.model.

[benjaoming]

Makes sense, and sorry about the regression. Seems that despite the test coverage, it's actually hard to change this code much.

I don't use DRF, so I hope that someone else will fix this. Would be happy to do a patch release.

[benjaoming]

And thanks for reporting so quickly 👍

[phillipuniverse]

@benjaoming loved how easy it was to contribute!! Candidate fix at #758.

[stianjensen]

Nice to avoid this crashing with a simple change, but is a Meta class outside of using a model serializer even valid/meaningful code in drf? Is it not only used to define how to auto-generate a serailizer class from a model?

[phillipuniverse]

but is a Meta class outside of using a model serializer even valid/meaningful code in drf

@stianjensen yes, there are multiple examples from the DRF docs like multi-field validators.

Also consider inheritance, where maybe a parent serializer class declares some fields as read only and a subclass declares them as not (or vice-versa).