Fixed #35831 -- Documented the model form meta API in model form reference docs.

Co-authored-by: Jonathan <3218047+jernwerber@users.noreply.github.com>
Co-authored-by: Mustafa <117516335+mspirbhai@users.noreply.github.com>

docs/ref/forms/models.txt

@@ -1,15 +1,188 @@
-====================
+===========
-Model Form Functions
+Model forms
-====================
+===========
-
-Model Form API reference. For introductory material about model forms, see the
-:doc:`/topics/forms/modelforms` topic guide.
 
 .. module:: django.forms.models
-   :synopsis: Django's functions for building model forms and formsets.
+    :synopsis: ModelForm API reference for inner ``Meta`` class and factory
+        functions
+
+.. currentmodule:: django.forms
+
+``ModelForm`` API reference. For introductory material about using a
+``ModelForm``, see the :doc:`/topics/forms/modelforms` topic guide.
+
+Model form ``Meta`` API
+=======================
+
+.. class:: ModelFormOptions
+
+The ``_meta`` API is used to build forms that reflect a Django model. It is
+accessible through the ``_meta`` attribute of each model form, and is an
+``django.forms.models.ModelFormOptions`` instance.
+
+The structure of the generated form can be customized by defining metadata
+options as attributes of an inner ``Meta`` class. For example::
+
+    from django.forms import ModelForm
+    from myapp.models import Book
+
+
+    class BookForm(ModelForm):
+        class Meta:
+            model = Book
+            fields = ["title", "author"]
+            help_texts = {
+                "title": "The title of the book",
+                "author": "The author of the book",
+            }
+            # ... other attributes
+
+Required attributes are :attr:`~ModelFormOptions.model`, and either
+:attr:`~ModelFormOptions.fields` or :attr:`~ModelFormOptions.exclude`. All
+other ``Meta`` attributes are optional.
+
+Optional attributes, other than :attr:`~ModelFormOptions.localized_fields` and
+:attr:`~ModelFormOptions.formfield_callback`, expect a dictionary that maps a
+model field name to a value. Any field that is not defined in the dictionary
+falls back to the field's default value.
+
+.. admonition:: Invalid field names
+
+    Invalid or excluded field names in an optional dictionary attribute have no
+    effect, since fields that are not included are not accessed.
+
+.. admonition:: Invalid Meta class attributes
+
+    You may define any attribute on a ``Meta`` class. Typos or incorrect
+    attribute names do not raise an error.
+
+``error_messages``
+------------------
+
+.. attribute:: ModelFormOptions.error_messages
+
+    A dictionary that maps a model field name to a dictionary of error message
+    keys (``null``, ``blank``, ``invalid``, ``unique``, etc.) mapped to custom
+    error messages.
+
+    When a field is not specified, Django will fall back on the error messages
+    defined in that model field's :attr:`django.db.models.Field.error_messages`
+    and then finally on the default error messages for that field type.
+
+``exclude``
+-----------
+
+.. attribute:: ModelFormOptions.exclude
+
+    A tuple or list of :attr:`~ModelFormOptions.model` field names to be
+    excluded from the form.
+
+    Either :attr:`~ModelFormOptions.fields` or
+    :attr:`~ModelFormOptions.exclude` must be set. If neither are set, an
+    :class:`~django.core.exceptions.ImproperlyConfigured` exception will be
+    raised. If :attr:`~ModelFormOptions.exclude` is set and
+    :attr:`~ModelFormOptions.fields` is unset, all model fields, except for
+    those specified in :attr:`~ModelFormOptions.exclude`, are included in the
+    form.
+
+``field_classes``
+-----------------
+
+.. attribute:: ModelFormOptions.field_classes
+
+    A dictionary that maps a model field name to a :class:`~django.forms.Field`
+    class, which overrides the ``form_class`` used in the model field's
+    :meth:`.Field.formfield` method.
+
+    When a field is not specified, Django will fall back on the model field's
+    :ref:`default field class <model-form-field-types>`.
+
+``fields``
+----------
+
+.. attribute:: ModelFormOptions.fields
+
+    A tuple or list of :attr:`~ModelFormOptions.model` field names to be
+    included in the form. The value ``'__all__'`` can be used to specify that
+    all fields should be included.
+
+    If any field is specified in :attr:`~ModelFormOptions.exclude`, this will
+    not be included in the form despite being specified in
+    :attr:`~ModelFormOptions.fields`.
+
+    Either :attr:`~ModelFormOptions.fields` or
+    :attr:`~ModelFormOptions.exclude` must be set. If neither are set, an
+    :class:`~django.core.exceptions.ImproperlyConfigured` exception will be
+    raised.
+
+``formfield_callback``
+----------------------
+
+.. attribute:: ModelFormOptions.formfield_callback
+
+    A function or callable that takes a model field and returns a
+    :class:`django.forms.Field` object.
+
+``help_texts``
+--------------
+
+.. attribute:: ModelFormOptions.help_texts
+
+    A dictionary that maps a model field name to a help text string.
+
+    When a field is not specified, Django will fall back on that model field's
+    :attr:`~django.db.models.Field.help_text`.
+
+``labels``
+----------
+
+.. attribute:: ModelFormOptions.labels
+
+    A dictionary that maps a model field names to a label string.
+
+    When a field is not specified, Django will fall back on that model field's
+    :attr:`~django.db.models.Field.verbose_name` and then the field's attribute
+    name.
+
+``localized_fields``
+--------------------
+
+.. attribute:: ModelFormOptions.localized_fields
+
+    A tuple or list of :attr:`~ModelFormOptions.model` field names to be
+    localized. The value ``'__all__'`` can be used to specify that all fields
+    should be localized.
+
+    By default, form fields are not localized, see
+    :ref:`enabling localization of fields
+    <modelforms-enabling-localization-of-fields>` for more details.
+
+``model``
+---------
+
+.. attribute:: ModelFormOptions.model
+
+    Required. The :class:`django.db.models.Model` to be used for the
+    :class:`~django.forms.ModelForm`.
+
+``widgets``
+-----------
+
+.. attribute:: ModelFormOptions.widgets
+
+    A dictionary that maps a model field name to a
+    :class:`django.forms.Widget`.
+
+    When a field is not specified, Django will fall back on the default widget
+    for that particular type of :class:`django.db.models.Field`.
+
+Model form factory functions
+============================
+
+.. currentmodule:: django.forms.models
 
 ``modelform_factory``
-=====================
+---------------------
 
 .. function:: 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, field_classes=None)
 
@@ -51,7 +224,7 @@ Model Form API reference. For introductory material about model forms, see the
     in an :exc:`~django.core.exceptions.ImproperlyConfigured` exception.
 
 ``modelformset_factory``
-========================
+------------------------
 
 .. function:: 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, widgets=None, validate_max=False, localized_fields=None, labels=None, help_texts=None, error_messages=None, min_num=None, validate_min=False, field_classes=None, absolute_max=None, can_delete_extra=True, renderer=None, edit_only=False)
 
@@ -74,7 +247,7 @@ Model Form API reference. For introductory material about model forms, see the
     See :ref:`model-formsets` for example usage.
 
 ``inlineformset_factory``
-=========================
+-------------------------
 
 .. function:: inlineformset_factory(parent_model, model, form=ModelForm, formset=BaseInlineFormSet, fk_name=None, fields=None, exclude=None, extra=3, can_order=False, can_delete=True, max_num=None, formfield_callback=None, widgets=None, validate_max=False, localized_fields=None, labels=None, help_texts=None, error_messages=None, min_num=None, validate_min=False, field_classes=None, absolute_max=None, can_delete_extra=True, renderer=None, edit_only=False)
 

docs/topics/forms/modelforms.txt

@@ -38,6 +38,8 @@ For example:
     >>> article = Article.objects.get(pk=1)
     >>> form = ArticleForm(instance=article)
 
+.. _model-form-field-types:
+
 Field types
 -----------
 
@@ -683,6 +685,8 @@ the field declaratively and setting its ``validators`` parameter::
     See the :doc:`form field documentation </ref/forms/fields>` for more
     information on fields and their arguments.
 
+.. _modelforms-enabling-localization-of-fields:
+
 Enabling localization of fields
 -------------------------------