Ticket #17271: none_custom_qs.patch

django/db/models/manager.py

@@ -46 +46 @@
     # Tracks each time a Manager instance is created. Used to retain order.
     creation_counter = 0
 
-    def __init__(self):
+    def __init__(self, queryset_cls=None):
         super(Manager, self).__init__()
         self._set_creation_counter()
         self.model = None
         self._inherited = False
         self._db = None
+        self._queryset_cls = queryset_cls or QuerySet
 
     def contribute_to_class(self, model, name):
         # TODO: Use weakref because of possible memory leak / circular reference.
@@ -101 +102 @@
     #######################
 
     def get_empty_query_set(self):
-        return EmptyQuerySet(self.model, using=self._db)
+        return self._queryset_cls(self.model, using=self._db).none()
 
     def get_query_set(self):
         """Returns a new QuerySet object.  Subclasses can override this method
         to easily customize the behavior of the Manager.
         """
-        return QuerySet(self.model, using=self._db)
+        return self._queryset_cls(self.model, using=self._db)
 
     def none(self):
         return self.get_empty_query_set()

django/db/models/query.py

@@ -582 +582 @@
         """
         Returns an empty QuerySet.
         """
-        return self._clone(klass=EmptyQuerySet)
+        klass = type(
+            "_InstrumentedEmptyQuerySet_%s" % self.__class__.__name__,
+            (EmptyQuerySet, self.__class__), {})
+        return self._clone(klass=klass)
 
     ##################################################################
     # PUBLIC METHODS THAT ALTER ATTRIBUTES AND RETURN A NEW QUERYSET #

tests/modeltests/lookup/models.py

@@ -5 +5 @@
 """
 
 from django.db import models
+from django.db.models.query import QuerySet
 
+class CustomArticleQuerySet(QuerySet):
+
+    def have_author1(self):
+        return self.filter(author__name='Author 1')
 
 class Author(models.Model):
     name = models.CharField(max_length=100)
@@ -13 +18 @@
         ordering = ('name', )
 
 class Article(models.Model):
+    objects = models.Manager()
+    custom_manager = models.Manager(CustomArticleQuerySet)
+
     headline = models.CharField(max_length=100)
     pub_date = models.DateTimeField()
     author = models.ForeignKey(Author, blank=True, null=True)

tests/modeltests/lookup/tests.py

@@ -450 +450 @@
             [article for article in Article.objects.none().iterator()],
             [])
 
+    def test_none_custom_qs(self):
+        self.assertQuerysetEqual(Article.custom_manager.none(), [])
+        self.assertQuerysetEqual(
+            Article.custom_manager.none().have_author1(),
+            [])
+
     def test_in(self):
         # using __in with an empty list should return an empty query set
         self.assertQuerysetEqual(Article.objects.filter(id__in=[]), [])