'exclude' does not work with lists containing a 'None' element.

[stillwater.ke@…]

For example:

Entry.objects.exclude(foo__in=[None, 1])

It is supposed to return all items whose foo field is not None or 1, but it actually returns an empty query set.

[Anssi Kääriäinen]

This is a known failure (tested in queries/tests.py, test_col_not_in_list_containing_null()).

This is somewhat hard to fix as SQL's "somecol NOT IN lst_containing_null" is weird - it will always return False (well, technically UNKNOWN but this doesn't matter here), and this is what causes the bug.

It would be possible to check for presence of None in the given list. If present, remove it and add in a proper IS NULL check instead. But then a query like .exclude(somecol__in=qs_containig_null) would work differently from .exclude(somecol__in=list(qs_containig_null)). I guess that could be classified as known abstraction leak.

[Aymeric Augustin]

Let's not be too smart... NULL in SQL is nowhere near as consistent as None in Python because of SQL's tri-valued boolean logic; we cannot hide this.