JSONField.default not applied in admin

[Jannis Vajen]

Consider a model like this:

class Example(models.Model):
    json = JSONField(
        default=list,
        blank=True
    )

Creating an object programmatically works and applies the default value just fine. Saving an object with an empty value for the JSONField triggers an IntegrityError because Django tries to save an object with null instead of the default.

I'm not sure whether this ticket is a duplicate of #27697 but I think this issue with the ignored default may have a different origin.

[Tim Graham]

Yes, I think this is a duplicate of #27697, although the desired behavior you describe isn't how Django uses model field defaults. Those defaults are only used to populate the initial the form. If a user removes that value, the default isn't called again when the form is submitted.