Hook for default QuerySet filtering defined on the QuerySet itself.

[Loic Bistuer]

Django 1.7 brought managers automatically created from QuerySet which replaces defining a custom manager for the purpose of defining reusable methods. Refs #20625.

One use-case remains inelegant: using a custom QuerySet with default QuerySet customization/filtering:

BaseCustomManager = Manager.from_queryset(CustomQueryset)

class CustomManager (BaseCustomManager ):
    def get_queryset(self):
        queryset = super(Manager, self).get_queryset()
        return queryset.filter(...)

This ticket proposes adding a hook on QuerySet to enable this without requiring a custom Manager.

[Loic Bistuer]

It's worth noting that QuerySet.__init__() can't be used for providing such initialization/customization:

• QuerySet are often cloned, and the customization should only ever apply once.
• QuerySet methods return a cloned QuerySet instance and __init__ can't return a different instance.

So far the best option I can think of is a hook called externally by the manager.

POC with a QuerySet.get_initial_queryset() method ​https://github.com/loic/django/compare/ticket23533