diff --git a/django/forms/forms.py b/django/forms/forms.py index 490d9c2c3b..15c3e2c3f8 100644 --- a/django/forms/forms.py +++ b/django/forms/forms.py @@ -11,7 +11,7 @@ import warnings from django.core.exceptions import ValidationError from django.forms.fields import Field, FileField from django.forms.utils import flatatt, ErrorDict, ErrorList -from django.forms.widgets import Media, media_property, TextInput, Textarea +from django.forms.widgets import Media, MediaDefiningClass, TextInput, Textarea from django.utils.html import conditional_escape, format_html from django.utils.encoding import smart_text, force_text, python_2_unicode_compatible from django.utils.safestring import mark_safe @@ -29,6 +29,7 @@ def pretty_name(name): return '' return name.replace('_', ' ').capitalize() + def get_declared_fields(bases, attrs, with_base_fields=True): """ Create a list of form field instances from the passed in 'attrs', plus any @@ -40,6 +41,13 @@ def get_declared_fields(bases, attrs, with_base_fields=True): used. The distinction is useful in ModelForm subclassing. Also integrates any additional media definitions. """ + + warnings.warn( + "get_declared_fields is deprecated and will be removed in Django 1.9.", + PendingDeprecationWarning, + stacklevel=2, + ) + fields = [(field_name, attrs.pop(field_name)) for field_name, obj in list(six.iteritems(attrs)) if isinstance(obj, Field)] fields.sort(key=lambda x: x[1].creation_counter) @@ -57,19 +65,42 @@ def get_declared_fields(bases, attrs, with_base_fields=True): return OrderedDict(fields) -class DeclarativeFieldsMetaclass(type): + +class DeclarativeFieldsMetaclass(MediaDefiningClass): """ - Metaclass that converts Field attributes to a dictionary called - 'base_fields', taking into account parent class 'base_fields' as well. + Metaclass that collects Fields declared on the base classes. """ - def __new__(cls, name, bases, attrs): - attrs['base_fields'] = get_declared_fields(bases, attrs) - new_class = super(DeclarativeFieldsMetaclass, - cls).__new__(cls, name, bases, attrs) - if 'media' not in attrs: - new_class.media = media_property(new_class) + def __new__(mcs, name, bases, attrs): + # Collect fields from current class. + current_fields = [] + for key, value in list(attrs.items()): + if isinstance(value, Field): + current_fields.append((key, value)) + attrs.pop(key) + current_fields.sort(key=lambda x: x[1].creation_counter) + attrs['declared_fields'] = OrderedDict(current_fields) + + new_class = (super(DeclarativeFieldsMetaclass, mcs) + .__new__(mcs, name, bases, attrs)) + + # Walk through the MRO. + declared_fields = OrderedDict() + for base in reversed(new_class.__mro__): + # Collect fields from base class. + if hasattr(base, 'declared_fields'): + declared_fields.update(base.declared_fields) + + # Field shadowing. + for attr in base.__dict__.keys(): + if attr in declared_fields: + declared_fields.pop(attr) + + new_class.base_fields = declared_fields + new_class.declared_fields = declared_fields + return new_class + @python_2_unicode_compatible class BaseForm(object): # This is the main implementation of all the Form logic. Note that this @@ -398,6 +429,7 @@ class BaseForm(object): """ return [field for field in self if not field.is_hidden] + class Form(six.with_metaclass(DeclarativeFieldsMetaclass, BaseForm)): "A collection of Fields, plus their associated data." # This is a separate class from BaseForm in order to abstract the way @@ -406,6 +438,7 @@ class Form(six.with_metaclass(DeclarativeFieldsMetaclass, BaseForm)): # to define a form using declarative syntax. # BaseForm itself has no way of designating self.fields. + @python_2_unicode_compatible class BoundField(object): "A Field plus data" diff --git a/django/forms/models.py b/django/forms/models.py index c05c452383..1a6e7d2a7a 100644 --- a/django/forms/models.py +++ b/django/forms/models.py @@ -10,11 +10,11 @@ import warnings from django.core.exceptions import ValidationError, NON_FIELD_ERRORS, FieldError from django.forms.fields import Field, ChoiceField -from django.forms.forms import BaseForm, get_declared_fields +from django.forms.forms import DeclarativeFieldsMetaclass, BaseForm from django.forms.formsets import BaseFormSet, formset_factory from django.forms.utils import ErrorList from django.forms.widgets import (SelectMultiple, HiddenInput, - MultipleHiddenInput, media_property, CheckboxSelectMultiple) + MultipleHiddenInput, CheckboxSelectMultiple) from django.utils.encoding import smart_text, force_text from django.utils import six from django.utils.text import get_text_list, capfirst @@ -61,6 +61,7 @@ def construct_instance(form, instance, fields=None, exclude=None): return instance + def save_instance(form, instance, fields=None, fail_message='saved', commit=True, exclude=None, construct=True): """ @@ -138,6 +139,7 @@ def model_to_dict(instance, fields=None, exclude=None): data[f.name] = f.value_from_object(instance) return data + def fields_for_model(model, fields=None, exclude=None, widgets=None, formfield_callback=None, localized_fields=None, labels=None, help_texts=None, error_messages=None): @@ -207,6 +209,7 @@ def fields_for_model(model, fields=None, exclude=None, widgets=None, ) return field_dict + class ModelFormOptions(object): def __init__(self, options=None): self.model = getattr(options, 'model', None) @@ -219,22 +222,16 @@ class ModelFormOptions(object): self.error_messages = getattr(options, 'error_messages', None) -class ModelFormMetaclass(type): - def __new__(cls, name, bases, attrs): +class ModelFormMetaclass(DeclarativeFieldsMetaclass): + def __new__(mcs, name, bases, attrs): formfield_callback = attrs.pop('formfield_callback', None) - try: - parents = [b for b in bases if issubclass(b, ModelForm)] - except NameError: - # We are defining ModelForm itself. - parents = None - declared_fields = get_declared_fields(bases, attrs, False) - new_class = super(ModelFormMetaclass, cls).__new__(cls, name, bases, - attrs) - if not parents: + + new_class = (super(ModelFormMetaclass, mcs) + .__new__(mcs, name, bases, attrs)) + + if bases == (BaseModelForm,): return new_class - if 'media' not in attrs: - new_class.media = media_property(new_class) opts = new_class._meta = ModelFormOptions(getattr(new_class, 'Meta', None)) # We check if a string was passed to `fields` or `exclude`, @@ -253,7 +250,6 @@ class ModelFormMetaclass(type): if opts.model: # If a model is defined, extract form fields from it. - if opts.fields is None and opts.exclude is None: # This should be some kind of assertion error once deprecation # cycle is complete. @@ -263,7 +259,7 @@ class ModelFormMetaclass(type): DeprecationWarning, stacklevel=2) if opts.fields == ALL_FIELDS: - # sentinel for fields_for_model to indicate "get the list of + # Sentinel for fields_for_model to indicate "get the list of # fields from the model" opts.fields = None @@ -274,8 +270,8 @@ class ModelFormMetaclass(type): # make sure opts.fields doesn't specify an invalid field none_model_fields = [k for k, v in six.iteritems(fields) if not v] - missing_fields = set(none_model_fields) - \ - set(declared_fields.keys()) + missing_fields = (set(none_model_fields) - + set(new_class.declared_fields.keys())) if missing_fields: message = 'Unknown field(s) (%s) specified for %s' message = message % (', '.join(missing_fields), @@ -283,13 +279,15 @@ class ModelFormMetaclass(type): raise FieldError(message) # Override default model fields with any custom declared ones # (plus, include all the other declared fields). - fields.update(declared_fields) + fields.update(new_class.declared_fields) else: - fields = declared_fields - new_class.declared_fields = declared_fields + fields = new_class.declared_fields + new_class.base_fields = fields + return new_class + class BaseModelForm(BaseForm): def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None, initial=None, error_class=ErrorList, label_suffix=None, @@ -438,9 +436,11 @@ class BaseModelForm(BaseForm): save.alters_data = True + class ModelForm(six.with_metaclass(ModelFormMetaclass, BaseModelForm)): pass + def modelform_factory(model, form=ModelForm, fields=None, exclude=None, formfield_callback=None, widgets=None, localized_fields=None, labels=None, help_texts=None, error_messages=None): @@ -780,6 +780,7 @@ class BaseModelFormSet(BaseFormSet): form.fields[self._pk_field.name] = ModelChoiceField(qs, initial=pk_value, required=False, widget=widget) super(BaseModelFormSet, self).add_fields(form, index) + def modelformset_factory(model, form=ModelForm, formfield_callback=None, formset=BaseModelFormSet, extra=1, can_delete=False, can_order=False, max_num=None, fields=None, exclude=None, @@ -1021,6 +1022,7 @@ class InlineForeignKeyField(Field): def _has_changed(self, initial, data): return False + class ModelChoiceIterator(object): def __init__(self, field): self.field = field @@ -1047,6 +1049,7 @@ class ModelChoiceIterator(object): def choice(self, obj): return (self.field.prepare_value(obj), self.field.label_from_instance(obj)) + class ModelChoiceField(ChoiceField): """A ChoiceField whose choices are a model QuerySet.""" # This class is a subclass of ChoiceField for purity, but it doesn't @@ -1141,6 +1144,7 @@ class ModelChoiceField(ChoiceField): data_value = data if data is not None else '' return force_text(self.prepare_value(initial_value)) != force_text(data_value) + class ModelMultipleChoiceField(ModelChoiceField): """A MultipleChoiceField whose choices are a model QuerySet.""" widget = SelectMultiple diff --git a/django/forms/widgets.py b/django/forms/widgets.py index 67befcfbe0..e80584a5c7 100644 --- a/django/forms/widgets.py +++ b/django/forms/widgets.py @@ -131,12 +131,16 @@ def media_property(cls): return property(_media) class MediaDefiningClass(type): - "Metaclass for classes that can have media definitions" - def __new__(cls, name, bases, attrs): - new_class = super(MediaDefiningClass, cls).__new__(cls, name, bases, - attrs) + """ + Metaclass for classes that can have media definitions. + """ + def __new__(mcs, name, bases, attrs): + new_class = (super(MediaDefiningClass, mcs) + .__new__(mcs, name, bases, attrs)) + if 'media' not in attrs: new_class.media = media_property(new_class) + return new_class @python_2_unicode_compatible diff --git a/docs/internals/deprecation.txt b/docs/internals/deprecation.txt index a965627a1c..b584a28ba1 100644 --- a/docs/internals/deprecation.txt +++ b/docs/internals/deprecation.txt @@ -467,6 +467,8 @@ these changes. * The ``use_natural_keys`` argument for ``serializers.serialize()`` will be removed. Use ``use_natural_foreign_keys`` instead. +* ``django.forms.get_declared_fields`` will be removed. + 2.0 --- diff --git a/docs/ref/forms/api.txt b/docs/ref/forms/api.txt index 14092512dc..c15f748308 100644 --- a/docs/ref/forms/api.txt +++ b/docs/ref/forms/api.txt @@ -854,6 +854,13 @@ classes::
  • Instrument:
  • Haircut type:
    • +.. versionadded:: 1.7 + +* It's possible to opt-out from a ``Field`` inherited from a parent class by + shadowing it. While any non-``Field`` value works for this purpose, it's + recommended to use ``None`` to make it explicit that a field is being + nullified. + .. _form-prefix: Prefixes for forms diff --git a/docs/releases/1.7.txt b/docs/releases/1.7.txt index 7a49f13327..5c208e22ac 100644 --- a/docs/releases/1.7.txt +++ b/docs/releases/1.7.txt @@ -288,6 +288,14 @@ Forms :func:`~django.forms.formsets.formset_factory` to allow validating a minimum number of submitted forms. +* The metaclasses used by ``Form`` and ``ModelForm`` have been reworked to + support more inheritance scenarios. The previous limitation that prevented + inheriting from both ``Form`` and ``ModelForm`` simultaneously have been + removed as long as ``ModelForm`` appears first in the MRO. + +* It's now possible to opt-out from a ``Form`` field declared in a parent class + by shadowing it with a non-``Field`` value. + Internationalization ^^^^^^^^^^^^^^^^^^^^ @@ -513,6 +521,12 @@ Miscellaneous still worked, even though it was not documented or officially supported. If you're still using it, please update to the current :setting:`CACHES` syntax. +* The default ordering of ``Form`` fields in case of inheritance has changed to + follow normal Python MRO. Fields are now discovered by iterating through the + MRO in reverse with the topmost class coming last. This only affects you if + you relied on the default field ordering while having fields defined on both + the current class *and* on a parent ``Form``. + Features deprecated in 1.7 ========================== diff --git a/docs/topics/forms/modelforms.txt b/docs/topics/forms/modelforms.txt index c65c705a58..2a48aa75dc 100644 --- a/docs/topics/forms/modelforms.txt +++ b/docs/topics/forms/modelforms.txt @@ -644,11 +644,24 @@ There are a couple of things to note, however. used. This means the child's ``Meta``, if it exists, otherwise the ``Meta`` of the first parent, etc. -* For technical reasons, a subclass cannot inherit from both a ``ModelForm`` - and a ``Form`` simultaneously. +.. versionchanged:: 1.7 -Chances are these notes won't affect you unless you're trying to do something -tricky with subclassing. +* It's possible to inherit from both ``Form`` and ``ModelForm`` simultaneuosly, + however, you must ensure that ``ModelForm`` appears first in the MRO. This is + because these classes rely on different metaclasses and a class can only have + one metaclass. + +.. versionadded:: 1.7 + +* It's possible to opt-out from a ``Field`` inherited from a parent class by + shadowing it. While any non-``Field`` value works for this purpose, it's + recommended to use ``None`` to make it explicit that a field is being + nullified. + + You can only use this technique to opt out from a field defined declaratively + by a parent class; it won't prevent the ``ModelForm`` metaclass from generating + a default field. To opt-out from default fields, see + :ref:`controlling-fields-with-fields-and-exclude`. .. _modelforms-factory: @@ -748,6 +761,8 @@ instances of the model, you can specify an empty QuerySet:: >>> AuthorFormSet(queryset=Author.objects.none()) +.. _controlling-fields-with-fields-and-exclude: + Controlling which fields are used with ``fields`` and ``exclude`` ----------------------------------------------------------------- diff --git a/tests/forms_tests/tests/test_forms.py b/tests/forms_tests/tests/test_forms.py index 1182be3929..33cf24f7c6 100644 --- a/tests/forms_tests/tests/test_forms.py +++ b/tests/forms_tests/tests/test_forms.py @@ -1302,10 +1302,10 @@ class FormsTestCase(TestCase): haircut_type = CharField() b = Beatle(auto_id=False) - self.assertHTMLEqual(b.as_ul(), """
  • First name:
    • + self.assertHTMLEqual(b.as_ul(), """
  • Instrument:
    • +
  • First name:
  • Last name:
  • Birthday:
    • -
  • Instrument:
  • Haircut type:
    • """) def test_forms_with_prefixes(self): diff --git a/tests/model_forms/tests.py b/tests/model_forms/tests.py index 8acc88b33f..f6e9a886a2 100644 --- a/tests/model_forms/tests.py +++ b/tests/model_forms/tests.py @@ -1802,3 +1802,39 @@ class M2mHelpTextTest(TestCase): html = form.as_p() self.assertInHTML('