ArrayField default is an empty string and not None

[ddaan]

Considering this class (from tests.postgres_tests.models):

class NullableIntegerArrayModel(models.Model):
    field = ArrayField(models.IntegerField(), blank=True, null=True)

When I save it directly after initialization it will result in an error

django.db.utils.DataError: array value must start with "{" or dimension information
LINE 1: ...ests_nullableintegerarraymodel" ("field") VALUES () RETURN...

This test will reproduce the error

    def test_default_null(self):
        instance = NullableIntegerArrayModel()
        instance.save()
        loaded = NullableIntegerArrayModel.objects.get(pk=instance.pk)
        self.assertEqual(loaded.field, None)
        self.assertEqual(instance.field, loaded.field)

[Remco Gerlich]

Only the first two lines of the test are needed, it's the call to .save() that crashes.

The exact same thing happens with a normal IntegerArrayModel, it's not specific to the Nullable one.

get_default() in ArrayField defaults to returning '', it seems that should be None or [] depending on the value of self.null.

[Marc Tamlyn <marc.tamlyn@…>]

In 9a5a4361c577d14cad303019f14ebc6d1ec01674:

Merge pull request #3531 from ddaan/ticket_23834

fixed #23834 -- added test and fix to check for default null on ArrayField