Fixed #10356 -- Added pure-Python inheritance for models (a.k.a proxy models).

Large portions of this are needed for #5420, so I implemented it fully.
Thanks to Ryan Kelly for an initial patch to get this started.

Refs #5420.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10083 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/options.py

@@ -21,7 +21,7 @@ get_verbose_name = lambda class_name: re.sub('(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|
 DEFAULT_NAMES = ('verbose_name', 'db_table', 'ordering',
                  'unique_together', 'permissions', 'get_latest_by',
                  'order_with_respect_to', 'app_label', 'db_tablespace',
-                 'abstract', 'managed')
+                 'abstract', 'managed', 'proxy')
 
 class Options(object):
     def __init__(self, meta, app_label=None):
@@ -43,11 +43,15 @@ class Options(object):
         self.has_auto_field, self.auto_field = False, None
         self.abstract = False
         self.managed = True
+        self.proxy = False
+        self.proxy_for_model = None
         self.parents = SortedDict()
         self.duplicate_targets = {}
-        # Managers that have been inherited from abstract base classes. These
-        # are passed onto any children.
+
+        # To handle various inheritance situations, we need to track where
+        # managers came from (concrete or abstract base classes).
         self.abstract_managers = []
+        self.concrete_managers = []
 
     def contribute_to_class(self, cls, name):
         from django.db import connection
@@ -164,6 +168,15 @@ class Options(object):
             self.pk = field
             field.serialize = False
 
+    def setup_proxy(self, target):
+        """
+        Does the internal setup so that the current model is a proxy for
+        "target".
+        """
+        self.pk = target._meta.pk
+        self.proxy_for_model = target
+        self.db_table = target._meta.db_table
+
     def __repr__(self):
         return '<Options for %s>' % self.object_name