Fixed #11082 -- Ensured that subqueries used in an exclude(X__in=) clause aren't pre-evaluated. Thanks to Henry Andrews for the report, and clement for the fix.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10929 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -7,6 +7,8 @@ try:
 except NameError:
     from sets import Set as set     # Python 2.3 fallback
 
+from copy import deepcopy
+
 from django.db import connection, transaction, IntegrityError
 from django.db.models.aggregates import Aggregate
 from django.db.models.fields import DateField
@@ -40,6 +42,17 @@ class QuerySet(object):
     # PYTHON MAGIC METHODS #
     ########################
 
+    def __deepcopy__(self, memo):
+        """
+        Deep copy of a QuerySet doesn't populate the cache
+        """
+        obj_dict = deepcopy(self.__dict__, memo)
+        obj_dict['_iter'] = None
+
+        obj = self.__class__()
+        obj.__dict__.update(obj_dict)
+        return obj
+
     def __getstate__(self):
         """
         Allows the QuerySet to be pickled.