CODEWITHSUNDEEP
djangopython-2.7django-orm
user3761405
user3761405

Reputation: 58

django custom field to_python not called when using .values()

I have a simple, custom PctField that just multiplies the value by 100 or else sets it to 0.0 if it's null. This works fine in my code like:

class PctField(models.FloatField):
    __metaclass__ = models.SubfieldBase

    def __init__(self, *args, **kwargs):
        kwargs['blank'] = True
        kwargs['null'] = True
        super(PctField, self).__init__(*args, **kwargs)

    def to_python(self, value):
        if value is None:
            return 0.

        return value * 100


class TestModel(models.Model):
    id = models.IntegerField(primary_key=True)
    non_pct = models.FloatField(blank=True, null=True)
    pct = PctField()


test = TestModel.objects.get(id=18328)
print test.non_pct, test.pct  # prints 0.900227, 90.0227

test1 = TestModel.objects.filter(id=18328)
print test1[0].non_pct, test1[0].pct  # prints 0.900227, 90.0227

Later on in my code I was trying to limit the data I returned so I decided to start using .values() on the result and passing in the dynamic list of fields I needed. When I did this, my to_python function in my custom field no longer gets called.

test2 = TestModel.objects.filter(id=18328)
print test2.values(*['non_pct', 'pct'])[0]  # prints {'non_pct': 0.900227, 'pct': 0.900227}

Has anyone else seen this before? I'm using django 1.6.8....

Upvotes: 0

Views: 280

Answers (1)

A. Coady
A. Coady

Reputation: 57378

It's a known issue, though apparently still under debate after 6 years whether it's a real bug or a documentation bug.

Upvotes: 1

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