magic-removal: Added Manager.__get__ method that forbids access by instances. Also added unit tests. Thanks, rjwittams

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@1615 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/meta/__init__.py

@@ -1194,10 +1194,15 @@ class Model:
 
     __set_many_to_many_objects.alters_data = True
 
-class Manager:
+class Manager(object):
     def __init__(self, model_class):
         self.klass = model_class
 
+    def __get__(self, instance, type=None):
+        if instance != None:
+            raise AttributeError, "Manager isn't accessible via %s instances" % self.klass.__name__
+        return self
+
     def _prepare(self):
         # Creates some methods once self.klass._meta has been populated.
         if self.klass._meta.get_latest_by:

tests/modeltests/basic/models.py

@@ -180,6 +180,18 @@ False
 >>> Article.objects.get_pub_date_list('day', order='DESC')
 [datetime.datetime(2005, 7, 31, 0, 0), datetime.datetime(2005, 7, 30, 0, 0), datetime.datetime(2005, 7, 29, 0, 0), datetime.datetime(2005, 7, 28, 0, 0)]
 
+# An Article instance doesn't have access to the "objects" attribute.
+# That is only available as a class method.
+>>> a7.objects.get_list()
+Traceback (most recent call last):
+    ...
+AttributeError: Manager isn't accessible via Article instances
+
+>>> a7.objects
+Traceback (most recent call last):
+    ...
+AttributeError: Manager isn't accessible via Article instances
+
 """
 
 from django.conf import settings