Reverse relations for unsaved objects include objects with NULL foreign key

[treyh]

Model with parent relation and children reverse relation:

class TestModel(models.Model):
    parent = models.ForeignKey('self', blank=True, null=True, related_name='children')

Bug found while using model:

t = TestModel()
t.save()
u = TestModel()
u.children.all() # Incorrectly returns: [<TestModel: TestModel object>]
u.save()
u.children.all() # Correctly returns: []

[Russell Keith-Magee]

This is an edge case that exists when an object has been created, but not saved; at that point, the primary key of the object is NULL, so the reverse query does a lookup with that value.

The fix here will be to prevent related object lookups when pk=None.

[elbarto]

Tests added.

[elbarto]

New tests added.

[Julien Phalip]

Could you combine the fix and tests into one single diff patch?

[Luke Plant]

Ticket #17541 is a duplicate. I don't know which one to close at this point.

[Stavros Korokithakis]

As I said on the other ticket, please upgrade the severity of this. It has just caused entirely sane-looking code to delete over half our database rows. This needs to be fixed ASAP, the patch has been submitted over two years ago.

[Russell Keith-Magee]

Closing this one as a duplicate of #17541. It doesn't really matter which one we leave open, as long as there's only one ticket per problem.