Fixed #7621 -- Enable superclassing of the various metaclasses we use.

Also tidy up some initialisation code in django.db.models.base.ModelBase.
Thanks, Christian Tanzer.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7846 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -350,6 +350,7 @@ answer newbie questions, and generally made Django that much better:
     Swaroop C H <http://www.swaroopch.info>
     Aaron Swartz <http://www.aaronsw.com/>
     Ville Säävuori <http://www.unessa.net/>
+    Christian Tanzer <tanzer@swing.co.at>
     Tyler Tarabula <tyler.tarabula@gmail.com>
     Tyson Tate <tyson@fallingbullets.com>
     Frank Tegtmeyer <fte@fte.to>

django/db/models/base.py

@@ -31,19 +31,15 @@ except NameError:
 class ModelBase(type):
     "Metaclass for all models"
     def __new__(cls, name, bases, attrs):
-        # If this isn't a subclass of Model, don't do anything special.
-        try:
-            parents = [b for b in bases if issubclass(b, Model)]
-        except NameError:
-            # 'Model' isn't defined yet, meaning we're looking at Django's own
-            # Model class, defined below.
-            parents = []
+        super_new = super(ModelBase, cls).__new__
+        parents = [b for b in bases if isinstance(b, ModelBase)]
         if not parents:
-            return super(ModelBase, cls).__new__(cls, name, bases, attrs)
+            # If this isn't a subclass of Model, don't do anything special.
+            return super_new(cls, name, bases, attrs)
 
         # Create the class.
         module = attrs.pop('__module__')
-        new_class = type.__new__(cls, name, bases, {'__module__': module})
+        new_class = super_new(cls, name, bases, {'__module__': module})
         attr_meta = attrs.pop('Meta', None)
         abstract = getattr(attr_meta, 'abstract', False)
         if not attr_meta:

django/newforms/forms.py

@@ -56,7 +56,8 @@ class DeclarativeFieldsMetaclass(type):
     """
     def __new__(cls, name, bases, attrs):
         attrs['base_fields'] = get_declared_fields(bases, attrs)
-        return type.__new__(cls, name, bases, attrs)
+        return super(DeclarativeFieldsMetaclass,
+                     cls).__new__(cls, name, bases, attrs)
 
 class BaseForm(StrAndUnicode):
     # This is the main implementation of all the Form logic. Note that this