Add custom Q-object (add_to_query) support to QuerySet.filter() and QuerySet.exclude()

[Johannes Dollinger]

It would be nice if custom Q-objects could be transparently used in filter() and exclude() calls (if they provide an __invert__() method).

The following code illustrates the desired behaviour:

class QuerySet(models.query.QuerySet):
    def filter(self, *args, **kwargs):
        if not kwargs and len(args) == 1 and hasattr(args[0], 'add_to_query'):
            return self.complex_filter(args[0])
        return super(QuerySet, self).filter(*args, **kwargs)

    def exclude(self, *args, **kwargs):
        if not kwargs and len(args) == 1:
            return self.complex_filter(~args[0])
        return super(QuerySet, self).exclude(*args, **kwargs)

[Johannes Dollinger]

...

[Russell Keith-Magee]

In order to do this, we would need to formalize the interface that Q objects expose. I'm not sure we're in a position to do that at the moment. Long term, it's certainly a desirable goal, though.

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Anssi Kääriäinen]

We will add expressions support instead. This should allow users to do what is wanted in this ticket.