Inconsistent JSONField filtering for value None

[fre-db]

When a JSONField has a key with Value None , only filtering on __key__in=[None] works, while you'd expect you could also just filter on __key=None or __key__isnull=True.

Example below:

import django
print(django.__version__)
3.1.2
print(Model.objects.get(pk=99657).jsonfield)
{'key': None}
print(Model.objects.filter(jsonfield__key=None).filter(pk=99657).count())
0
print(Model.objects.filter(jsonfield__key__is_null=True).filter(pk=99657).count())
0
print(Model.objects.filter((jsonfield__key__in=[None]).filter(pk=99657).count())
1

[Mariusz Felisiak]

It works as expected for me:

>>> NullableJSONModel.objects.create(value={'key': None})
NullableJSONModel object (14)
>>> NullableJSONModel.objects.filter(value__key=None)
<QuerySet [<NullableJSONModel: NullableJSONModel object (14)>]>
>>> NullableJSONModel.objects.filter(value__key__isnull=True)  # This will return also JSONFields without the `key`.
<QuerySet [<NullableJSONModel: NullableJSONModel object (14)>]>
>>> NullableJSONModel.objects.filter(value__key__in=[None])
<QuerySet []>

See ​Storing and querying for None and ​Key, index, and path transforms docs.