Implemented subclassing Forms in newforms

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4506 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 12 insertions, 1 deletions

diff --git a/django/newforms/forms.py b/django/newforms/forms.py
index 0b90b09e2c..1032d02e35 100644
--- a/django/newforms/forms.py
+++ b/django/newforms/forms.py
@@ -31,10 +31,21 @@ class SortedDictFromList(SortedDict):
         return SortedDictFromList([(k, copy.copy(v)) for k, v in self.items()])
 
 class DeclarativeFieldsMetaclass(type):
-    "Metaclass that converts Field attributes to a dictionary called 'base_fields'."
+    """
+    Metaclass that converts Field attributes to a dictionary called
+    'base_fields', taking into account parent class 'base_fields' as well.
+    """
     def __new__(cls, name, bases, attrs):
         fields = [(field_name, attrs.pop(field_name)) for field_name, obj in attrs.items() if isinstance(obj, Field)]
         fields.sort(lambda x, y: cmp(x[1].creation_counter, y[1].creation_counter))
+
+        # If this class is subclassing another Form, add that Form's fields.
+        # Note that we loop over the bases in *reverse*. This is necessary in
+        # order to preserve the correct order of fields.
+        for base in bases[::-1]:
+            if hasattr(base, 'base_fields'):
+                fields = base.base_fields.items() + fields
+
         attrs['base_fields'] = SortedDictFromList(fields)
         return type.__new__(cls, name, bases, attrs)