Ticket #12915: formfield_callback_inheritance.diff

django/forms/models.py

@@ -179 +179 @@
 
 class ModelFormMetaclass(type):
     def __new__(cls, name, bases, attrs):
-        formfield_callback = attrs.pop('formfield_callback',
-                lambda f: f.formfield())
+        formfield_callback = attrs.pop('formfield_callback', None)
         try:
             parents = [b for b in bases if issubclass(b, ModelForm)]
         except NameError:
@@ -192 +191 @@
         if not parents:
             return new_class
 
+        # If formfield_callback is not present in the class definition,
+        # copy it from the parent class. 
+        if not formfield_callback:
+            for parent in parents:
+                formfield_callback = getattr(parent, 'formfield_callback', None)
+                if formfield_callback:
+                    break
+        if formfield_callback:
+            new_class.formfield_callback = staticmethod(formfield_callback)
+
         if 'media' not in attrs:
             new_class.media = media_property(new_class)
         opts = new_class._meta = ModelFormOptions(getattr(new_class, 'Meta', None))
         if opts.model:
             # If a model is defined, extract form fields from it.
             fields = fields_for_model(opts.model, opts.fields,
-                                      opts.exclude, formfield_callback)
+                                      opts.exclude, formfield_callback or (lambda f: f.formfield()))
             # Override default model fields with any custom declared ones
             # (plus, include all the other declared fields).
             fields.update(declared_fields)