newforms: Changed form_for_model() to ignore a field if its formfield() returns None, and changed AutoField.formfield() to return None

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4214 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/__init__.py

@@ -375,6 +375,9 @@ class AutoField(Field):
         super(AutoField, self).contribute_to_class(cls, name)
         cls._meta.has_auto_field = True
 
+    def formfield(self):
+        return None
+
 class BooleanField(Field):
     def __init__(self, *args, **kwargs):
         kwargs['blank'] = True

django/newforms/models.py

@@ -10,7 +10,12 @@ __all__ = ('form_for_model', 'form_for_fields')
 def form_for_model(model):
     "Returns a Form class for the given Django model class."
     opts = model._meta
-    fields = SortedDictFromList([(f.name, f.formfield()) for f in opts.fields + opts.many_to_many])
+    field_list = []
+    for f in opts.fields + opts.many_to_many:
+        formfield = f.formfield()
+        if formfield:
+            field_list.append((f.name, formfield))
+    fields = SortedDictFromList(field_list)
     return type(opts.object_name + 'Form', (BaseForm,), {'fields': fields, '_model_opts': opts})
 
 def form_for_fields(field_list):