Fixed #11956 -- Modified the handling of m2m relationships between subclasses....

            model=rel_model,

            core_filters={'%s__pk' % self.field.related_query_name(): instance._get_pk_val()},

            instance=instance,

            symmetrical=(self.field.rel.symmetrical and isinstance(instance, rel_model)),

            symmetrical=self.field.rel.symmetrical,

            source_field_name=self.field.m2m_field_name(),

            target_field_name=self.field.m2m_reverse_field_name(),

            reverse=False

        kwargs['rel'] = ManyToManyRel(to,

            related_name=kwargs.pop('related_name', None),

            limit_choices_to=kwargs.pop('limit_choices_to', None),

            symmetrical=kwargs.pop('symmetrical', True),

            symmetrical=kwargs.pop('symmetrical', to==RECURSIVE_RELATIONSHIP_CONSTANT),

            through=kwargs.pop('through', None))

        self.db_table = kwargs.pop('db_table', None)

    def __unicode__(self):

        return self.name

# Regression for #11956 -- a many to many to the base class

class TagCollection(Tag):

    tags = models.ManyToManyField(Tag, related_name='tag_collections')

    def __unicode__(self):

        return self.name

# A related_name is required on one of the ManyToManyField entries here because

# they are both addressable as reverse relations from Tag.

class Entry(models.Model):

>>> w.save()

>>> w.delete()

# Regression for #11956 -- You can add an object to a m2m with the

# base class without causing integrity errors

>>> c1 = TagCollection.objects.create(name='c1')

>>> c1.tags = [t1,t2]

>>> c1 = TagCollection.objects.get(name='c1')

>>> c1.tags.all()

[<Tag: t1>, <Tag: t2>]

>>> t1.tag_collections.all()

[<TagCollection: c1>]

"""

}