non_polymorphic() queryset member function added

DOCS.rst

@@ -235,15 +235,15 @@ existing polymorphic inheritance tree::
 Non-Polymorphic Queries
 -----------------------
 
->>> ModelA.base_objects.all()
+>>> ModelA.objects.all().non_polymorphic()
 .
 [ <ModelA: id 1, field1 (CharField)>,
   <ModelA: id 2, field1 (CharField)>,
   <ModelA: id 3, field1 (CharField)> ]
 
-Each polymorphic model has 'base_objects' defined as a normal
-Django manager. Of course, arbitrary custom managers may be
-added to the models as well.
+Except for the return of the of the base class objects, there are no
+changes in the behaviour of the queryset (i.e. the enhancements
+for ``filter()`` or ``instance_of()`` etc. still work as expected).
     
 About Queryset Methods
 ----------------------
@@ -270,8 +270,8 @@ About Queryset Methods
 
 +   ``get_real_instances(base_objects_list_or_queryset)`` allows you to turn a
     queryset or list  of base model objects efficiently into the real objects.
-    For example, you could do ``base_objects=ModelA.base_objects.extra(...)`` and
-    then call ``real_objects=ModelA.objects.get_real_instances(base_objects)``.
+    For example, you could do ``base_objects=ModelA.extra(...).non_polymorphic()``
+    and then call ``real_objects=ModelA.objects.get_real_instances(base_objects)``.
 
 *   ``values()`` & ``values_list()`` currently do not return polymorphic
     results. This may change in the future however. If you want to use these

polymorphic/query.py

@@ -42,6 +42,13 @@ class PolymorphicQuerySet(QuerySet):
         new.polymorphic_disabled = self.polymorphic_disabled
         return new
 
+    def non_polymorphic(self, *args, **kwargs):
+        """switch off polymorphic behaviour for this query.
+        When the queryset is evaluated, only objects of the type of the
+        base class used for this query are returned."""
+        self.polymorphic_disabled = True
+        return self
+
     def instance_of(self, *args):
         """Filter the queryset to only include the classes in args (and their subclasses).
         Implementation in _translate_polymorphic_filter_defnition."""

polymorphic/tests.py

@@ -289,6 +289,13 @@ __test__ = {"doctest": """
 >>> o.get_real_instance()
 <Model2C: id 3, field1 (CharField), field2 (CharField), field3 (CharField)>
 
+# non_polymorphic()
+>>> Model2A.objects.all().non_polymorphic()
+[ <Model2A: id 1, field1 (CharField)>,
+  <Model2A: id 2, field1 (CharField)>,
+  <Model2A: id 3, field1 (CharField)>,
+  <Model2A: id 4, field1 (CharField)> ]
+
 
 ### test inheritance pointers & _base_managers