AttributeError Exception raised when trying to bulk delete items in Django

Question

I'm trying to bulk delete all of the comments on a dev instance of my Django website and Django is raising an AttributeException.

I've got the following code on a python prompt:

>>> from django.contrib.comments.models import Comment
>>> Comment.objects.all().delete()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/jeff/.virtualenvs/osl_main-website/lib/python2.6/site-packages/django/db/models/query.py", line 441, in delete
    obj._collect_sub_objects(seen_objs)
  File "/home/jeff/.virtualenvs/osl_main-website/lib/python2.6/site-packages/django/db/models/base.py", line 569, in _collect_sub_objects
    sub_obj._collect_sub_objects(seen_objs, self, related.field.null)
  File "/home/jeff/.virtualenvs/osl_main-website/lib/python2.6/site-packages/django/db/models/base.py", line 585, in _collect_sub_objects
    delete_qs = rel_descriptor.delete_manager(self).all()
AttributeError: 'ReverseSingleRelatedObjectDescriptor' object has no attribute 'delete_manager'

I'm not sure as to why the delete statement is not working. Can anyone help me with why this isn't working and what I can do to fix it?

Additional details about my models:

I have another model called OslComment that inherits from Comment. I also have a Vote model that points to entries in OslComment.

BaseCommentAbstractModel

class BaseCommentAbstractModel(models.Model):
    """
    An abstract base class that any custom comment models probably should
    subclass.
    """

    # Content-object field
    content_type   = models.ForeignKey(ContentType,
            verbose_name=_('content type'),
            related_name="content_type_set_for_%(class)s")
    object_pk      = models.TextField(_('object ID'))
    content_object = generic.GenericForeignKey(ct_field="content_type", fk_field="object_pk")

    # Metadata about the comment
    site        = models.ForeignKey(Site)

Comment

class Comment(BaseCommentAbstractModel):
    """
    A user comment about some object.
    """

    # Who posted this comment? If ``user`` is set then it was an authenticated
    # user; otherwise at least user_name should have been set and the comment
    # was posted by a non-authenticated user.
    user        = models.ForeignKey(User, verbose_name=_('user'),
                    blank=True, null=True, related_name="%(class)s_comments")
    user_name   = models.CharField(_("user's name"), max_length=50, blank=True)
    user_email  = models.EmailField(_("user's email address"), blank=True)
    user_url    = models.URLField(_("user's URL"), blank=True)

    comment = models.TextField(_('comment'), max_length=COMMENT_MAX_LENGTH)

    # Metadata about the comment
    submit_date = models.DateTimeField(_('date/time submitted'), default=None)
    ip_address  = models.IPAddressField(_('IP address'), blank=True, null=True)
    is_public   = models.BooleanField(_('is public'), default=True,
                    help_text=_('Uncheck this box to make the comment effectively ' \
                                'disappear from the site.'))
    is_removed  = models.BooleanField(_('is removed'), default=False,
                    help_text=_('Check this box if the comment is inappropriate. ' \
                                'A "This comment has been removed" message will ' \
                                'be displayed instead.'))

OslComment

class OslComment(Comment):
    parent_comment = models.ForeignKey(Comment, blank=True, null=True, related_name='parent_comment')
    inline_to_object = models.BooleanField(default=False)
    edit_timestamp = models.DateTimeField()
    transformed_comment = models.TextField(editable=False)
    is_deleted_by_user = models.BooleanField(default=False)

Vote

class Vote(models.Model):
    """
    A vote on an object by a User.
    """
    user         = models.ForeignKey(User)
    content_type = models.ForeignKey(ContentType)
    object_id    = models.PositiveIntegerField()
    object       = generic.GenericForeignKey('content_type', 'object_id')
    vote         = models.SmallIntegerField(choices=SCORES)

Misc information:

Python Version: 2.6.5
Operating System: Linux Mint 9 (Linux 2.6.32-21-generic)
Django: 1.2
Database driver: postgresql_psycopg2 (2.2.1)

Answer 1

Edited: Originally I thought you couldn't do delete() on a QuerySet and was going to recommend you iterate over the items, but apparently you can do bulk deletes like that. Trying to iterate over the QuerySet might give you a better clue as to what's wrong, though.