forms.JSONField validator doesn't match documentation behavior

[Jake Klingensmith]

If you have a required JSONField on a model and you make a model form, the model form rejects falsey values as empty ([] for sure, possibly others as well). The documentation says that None is the empty value for the forms.JSONField.

I've seen similar documented issues with regards to the admin panel, not sure if they're running off the same code or not, but it doesn't seem to be resolved in this case.

For example:

class FooForm(forms.Form)
    bar = forms.JSONField(required=True)

# in shell
f = FooForm(data={"bar": []})
f.is_valid()  # False
f.errors       # {'bar': ['This field is required.']}

This contradicts the documentation, as well as the behavior of the JSON model field, so that JSON fields create undesirable behavior in ModelForms.

I'm using Django 3.2, not sure if this behavior is fixed in a later version.

[Mariusz Felisiak]

Duplicate of #26391.

[David Sanders]

Also just FYI the documentation is actually referring to what JSONField normalises the empty value to: ​https://github.com/django/django/blob/main/django/forms/fields.py#L1372 The documentation clarifies this normalisation: ​https://docs.djangoproject.com/en/5.0/ref/forms/fields/#django.forms.Field.required