Inconsistent field_name when validating schema

[matejsp]

There is inconsistent field_name meaning when validating fields:
raising ValidationError: it expected data_key as field_name
@marshmallow.validates: it expects field name

And the same issue for:

            raise ValidationError(
                {
                    "field_a": ["field_a must be greater than field_b"],
                    "field_b": ["field_a must be greater than field_b"],
                }
            )

Given the following code:

import marshmallow
from marshmallow import fields

class ApiKeySchema(marshmallow.Schema):
    ip_addresses = fields.String(required=True, load_from='ipAddresses', data_key='ipAddresses')

    @marshmallow.validates_schema(skip_on_field_errors=False)
    def validate_restricted_permission2(self, data, **kwargs) -> None:
        raise marshmallow.ValidationError({'ip_addresses': 'Some random error 2.'})

    @marshmallow.validates_schema(skip_on_field_errors=False)
    def validate_restricted_permission(self, data, **kwargs) -> None:
        if marshmallow.__version__.startswith('2.'):
            raise marshmallow.ValidationError('Some random error.', field_names=['ip_addresses'])
        else:
            raise marshmallow.ValidationError('Some random error.', field_name='ip_addresses')

    @marshmallow.validates(field_name='ip_addresses')
    def validate_ip_addresses(self, data) -> None:
        raise marshmallow.ValidationError('Some random field error.')


if __name__ == '__main__':
    print(marshmallow.__version__)
    schema = ApiKeySchema(strict=True) if marshmallow.__version__.startswith('2.') else ApiKeySchema()
    try:
        schema.load({'ipAddresses': 'bla'})
    except marshmallow.ValidationError as e:
        print(e.messages)

2.15.3
{'ip_addresses': ['Some random field error.', 'Some random error.'], '_schema': [{'ip_addresses': 'Some random error 2.'}]}

2.21.0
{'ipAddresses': ['Some random field error.'], 'ip_addresses': ['Some random error.', 'Some random error 2.']}

3.20.1
{'ipAddresses': ['Some random field error.'], 'ip_addresses': ['Some random error.', 'Some random error 2.']}

how it should be:
{'ipAddresses': ['Some random field error.', 'Some random error.', 'Some random error 2.']}

Changing both field_name to data_key values then it complains about non existing field on line: @marshmallow.validates(field_name='ipAddresses')

[lafrech]

Thanks for reporting. Looks like a bug indeed. data_key should be used consistently as error key.

[niviPy]

Can I work on this?

[lafrech]

Sure. Thanks.