magic-removal: model inheirtance can now be more than 1 level deep.

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2506 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/base.py

@@ -1,6 +1,6 @@
 import django.db.models.manipulators
 import django.db.models.manager
-from django.db.models.fields import AutoField, ImageField
+from django.db.models.fields import AutoField, ImageField, FieldDoesNotExist
 from django.db.models.fields.related import OneToOne, ManyToOne
 from django.db.models.related import RelatedObject
 from django.db.models.query import orderlist2sql, delete_objects
@@ -56,6 +56,10 @@ class ModelBase(type):
         # Add Fields inherited from parents
         for parent in new_class._meta.parents:
             for field in parent._meta.fields:
+                # Only add parent fields if they aren't defined for this class.
+                try:
+                    new_class._meta.get_field(field.name)
+                except FieldDoesNotExist:
                     field.contribute_to_class(new_class, field.name)
 
         new_class._prepare()

tests/modeltests/model_inheritance/models.py

@@ -19,9 +19,19 @@ class Restaurant(Place):
     def __repr__(self):
         return "%s the restaurant" % self.name
 
+class ItalianRestaurant(Restaurant):
+    serves_gnocchi = models.BooleanField()
+
+    def __repr__(self):
+        return "%s the italian restaurant" % self.name
+
 API_TESTS = """
 # Make sure Restaurant has the right fields in the right order.
 >>> [f.name for f in Restaurant._meta.fields]
 ['id', 'name', 'address', 'serves_hot_dogs', 'serves_pizza']
 
+# Make sure ItalianRestaurant has the right fields in the right order.
+>>> [f.name for f in ItalianRestaurant._meta.fields]
+['id', 'name', 'address', 'serves_hot_dogs', 'serves_pizza', 'serves_gnocchi']
+
 """