Fixed #12163 -- Corrected the unpickling of non-deferred models. Thanks to...

        defers = []

        pk_val = None

        if self._deferred:

            from django.db.models.query_utils import deferred_class_factory

            factory = deferred_class_factory

            for field in self._meta.fields:

                if isinstance(self.__class__.__dict__.get(field.attname),

                        DeferredAttribute):

                        # once.

                        obj = self.__class__.__dict__[field.attname]

                        model = obj.model_ref()

        return (model_unpickle, (model, defers), data)

        else:

            factory = simple_class_factory

        return (model_unpickle, (model, defers, factory), data)

    def _get_pk_val(self, meta=None):

        if not meta:

class Empty(object):

    pass

def model_unpickle(model, attrs):

def simple_class_factory(model, attrs):

    """Used to unpickle Models without deferred fields.

    We need to do this the hard way, rather than just using

    the default __reduce__ implementation, because of a

    __deepcopy__ problem in Python 2.4

    """

    return model

def model_unpickle(model, attrs, factory):

    """

    Used to unpickle Model subclasses with deferred fields.

    """

    from django.db.models.query_utils import deferred_class_factory

    cls = deferred_class_factory(model, attrs)

    cls = factory(model, attrs)

    return cls.__new__(cls)

model_unpickle.__safe_for_unpickle__ = True

>>> results[0].second_child.name

u'c2'

# Test for #12163 - Pickling error saving session with unsaved model instances.

>>> from django.contrib.sessions.backends.db import SessionStore

>>> SESSION_KEY = '2b1189a188b44ad18c35e1baac6ceead'

>>> item = Item()

>>> item._deferred

False

>>> s = SessionStore(SESSION_KEY)

>>> s.clear()

>>> s['item'] = item

>>> s.save()

>>> s = SessionStore(SESSION_KEY)

>>> s.modified = True

>>> s.save()

>>> i2 = s['item']

>>> i2._deferred # Item must still be non-deferred

False

# Finally, we need to flush the app cache for the defer module.

# Using only/defer creates some artifical entries in the app cache

# that messes up later tests. Purge all entries, just to be sure.