gistfile1.py

class QuerySetDoubleIteration(Exception):
    "A QuerySet was iterated over twice, you probably want to list() it."
    pass


# "Skinny" here means we use iterator by default, rather than
# ballooning in memory.
class SkinnyManager(Manager):
    def get_query_set(self):
        return SkinnyQuerySet(self.model, using=self._db)


class SkinnyQuerySet(QuerySet):
    def __len__(self):
        if getattr(self, 'has_run_before', False):
            raise TypeError("SkinnyQuerySet doesn't support __len__ after __iter__, if you *only* need a count you should use .count(), if you need to reuse the results you should coerce to a list and then len() that.")
        return super(SkinnyQuerySet, self).__len__()

    def __iter__(self):
        if self._result_cache is not None:
            # __len__ must have been run
            return iter(self._result_cache)

        has_run_before = getattr(self, 'has_run_before', False)
        if has_run_before:
            raise QuerySetDoubleIteration("This SkinnyQuerySet has already been iterated over once, you should assign it to a list if you want to reuse the data.")
        self.has_run_before = True

        return self.iterator()

gistfile2.txt

diff --git a/django_root/django/db/models/query.py b/django_root/django/db/models/query.py
index b8b2340..e679cfa 100644
--- a/django_root/django/db/models/query.py
+++ b/django_root/django/db/models/query.py
@@ -415,7 +415,7 @@ class QuerySet(object):
         assert self.query.can_filter(), \
                 "Cannot use 'limit' or 'offset' with delete."
 
-        del_query = self._clone()
+        del_query = self._clone(klass=QuerySet)
 
         # The delete is actually 2 queries - one to find related objects,
         # and one to delete. Make sure that the discovery of related