Models with a CharField as primary key

[ostcar]

If the primary key of a model with a JSONField is a CharField, a ValidateError occurs when setting the jsonfield.

Here are some tests that fail:

class JsonModelWithPK(models.Model):
    json = JSONField()
    key = models.CharField(max_length=255, primary_key=True)

class JSONPKTest(JSONFieldTest):
    json_model = JsonModelWithPK

[ostcar]

I played arround some more. The error has nothing to do with the CharField. It occurs when setting the primary key of the model. Here is a test that fails (in his first line):

    def test_set_pk(self):
        self.json_model.objects.create(id=42, json='test string')
        new_obj = self.json_model.objects.get(id=42)
        self.assertEqual(new_obj.json, 'test string')

The problem is related to #33. The fix from that issue does not help in this case, because In this line, the obj has a pk: https://github.com/bradjasper/django-jsonfield/blob/master/jsonfield/fields.py#L72

A workaround is to use ...create(pk=42, json='test_string').

[bradjasper]

@ostcar unfortunately I'm not sure how to solve this one.

The problem is being able to determine when a form is new vs when it's already been saved. This is needed to know when a string has already been JSON encoded.

In this case, you're passing an ID in which is tripping up the mechanism we use to perform this check.

Since there is a workaround, I'm going to suggest using that and close this. Sorry I don't have a better answer here.