Index: django/newforms/models.py =================================================================== --- django/newforms/models.py (revision 7003) +++ django/newforms/models.py (working copy) @@ -11,7 +11,7 @@ from django.core.exceptions import ImproperlyConfigured from util import ValidationError, ErrorList -from forms import BaseForm +from forms import BaseForm, get_declared_fields from fields import Field, ChoiceField, EMPTY_VALUES from widgets import Select, SelectMultiple, MultipleHiddenInput @@ -214,49 +214,38 @@ class ModelFormMetaclass(type): def __new__(cls, name, bases, attrs, formfield_callback=lambda f: f.formfield()): - 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 - declared_fields = SortedDict(fields) + fields = SortedDict() - opts = ModelFormOptions(attrs.get('Meta', None)) - attrs['_meta'] = opts - - # Don't allow more than one Meta model defenition in bases. The fields - # would be generated correctly, but the save method won't deal with - # more than one object. - base_models = [] - for base in bases: - base_opts = getattr(base, '_meta', None) - base_model = getattr(base_opts, 'model', None) - if base_model is not None: - base_models.append(base_model) - if len(base_models) > 1: - raise ImproperlyConfigured("%s's base classes define more than one model." % name) - - # If a model is defined, extract form fields from it and add them to base_fields - if attrs['_meta'].model is not None: - # Don't allow a subclass to define a different Meta model than a - # parent class has. Technically the right fields would be generated, - # but the save method will not deal with more than one model. + meta = attrs.get('Meta', None) + if meta is not None: + opts = ModelFormOptions(meta) + # If a model is defined, extract form fields from it + if opts.model is not None: + fields = fields_for_model(opts.model, opts.fields, + opts.exclude, formfield_callback) + else: + # No Meta options defined in the class. Search base classes, but + # don't allow more than one Meta definition. The fields would be + # generated correctly, but the save method won't deal with more + # than one object. Also, it wouldn't be clear what to do with + # multiple fields and exclude lists. + opts = None for base in bases: base_opts = getattr(base, '_meta', None) - base_model = getattr(base_opts, 'model', None) - if base_model and base_model is not opts.model: - raise ImproperlyConfigured('%s defines a different model than its parent.' % name) - model_fields = fields_for_model(opts.model, opts.fields, - opts.exclude, formfield_callback) - # fields declared in base classes override fields from the model - model_fields.update(declared_fields) - attrs['base_fields'] = model_fields - else: - attrs['base_fields'] = declared_fields + if base_opts is not None: + if opts is not None: + raise ImproperlyConfigured("%s's base classes define more than one Meta options." % name) + opts = base_opts + if opts is None: + # No Meta options defined neither in the class nor its base classes + opts = ModelFormOptions() + + attrs['_meta'] = opts + + # Fields declared explicitely override fields from the model + fields.update(get_declared_fields(bases, attrs)) + attrs['base_fields'] = fields return type.__new__(cls, name, bases, attrs) class BaseModelForm(BaseForm): Index: django/newforms/forms.py =================================================================== --- django/newforms/forms.py (revision 7003) +++ django/newforms/forms.py (working copy) @@ -22,23 +22,26 @@ name = name[0].upper() + name[1:] return name.replace('_', ' ') +def get_declared_fields(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 + + return SortedDict(fields) + class DeclarativeFieldsMetaclass(type): """ 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'] = SortedDict(fields) + attrs['base_fields'] = get_declared_fields(bases, attrs) return type.__new__(cls, name, bases, attrs) class BaseForm(StrAndUnicode): Index: docs/modelforms.txt =================================================================== --- docs/modelforms.txt (revision 7003) +++ docs/modelforms.txt (working copy) @@ -311,3 +311,11 @@ ... ... class Meta: ... model = Article + +Form inheritance +---------------- +As with the basic forms, you can extend and reuse forms by inheriting them. +The fields will be combined, but only the most recently declared Meta +definition will be used. If you do not include a Meta definition in a child +class, a Meta definition will be looked in its parent classes. Note that it is +not allowed to have more than one base class with the Meta defition.