Refs #23656 -- Required FormMixin.get_form() form_class parameter to be optional.

Per deprecation timeline.

django/views/generic/edit.py

-import inspect
-import warnings
-
 from django.core.exceptions import ImproperlyConfigured
 from django.forms import models as model_forms
 from django.http import HttpResponseRedirect
-from django.utils import six
-from django.utils.deprecation import RemovedInDjango110Warning
 from django.utils.encoding import force_text
 from django.views.generic.base import ContextMixin, TemplateResponseMixin, View
 from django.views.generic.detail import (
@@ -13,28 +8,7 @@ from django.views.generic.detail import (
 )
 
 
-class FormMixinBase(type):
-    def __new__(cls, name, bases, attrs):
-        get_form = attrs.get('get_form')
-        if get_form and inspect.isfunction(get_form):
-            try:
-                inspect.getcallargs(get_form, None)
-            except TypeError:
-                warnings.warn(
-                    "`%s.%s.get_form` method must define a default value for "
-                    "its `form_class` argument." % (attrs['__module__'], name),
-                    RemovedInDjango110Warning, stacklevel=2
-                )
-
-                def get_form_with_form_class(self, form_class=None):
-                    if form_class is None:
-                        form_class = self.get_form_class()
-                    return get_form(self, form_class=form_class)
-                attrs['get_form'] = get_form_with_form_class
-        return super(FormMixinBase, cls).__new__(cls, name, bases, attrs)
-
-
-class FormMixin(six.with_metaclass(FormMixinBase, ContextMixin)):
+class FormMixin(ContextMixin):
     """
     A mixin that provides a way to show and handle a form in a request.
     """

docs/ref/class-based-views/mixins-editing.txt

@@ -59,10 +59,6 @@ FormMixin
         :meth:`~django.views.generic.edit.FormMixin.get_form_kwargs`.
         If ``form_class`` isn't provided :meth:`get_form_class` will be used.
 
-        .. versionchanged:: 1.8
-
-            The ``form_class`` argument is not required anymore.
-
     .. method:: get_form_kwargs()
 
         Build the keyword arguments required to instantiate the form.

tests/generic_views/test_edit.py

 from __future__ import unicode_literals
 
-import warnings
-
 from django import forms
 from django.core.exceptions import ImproperlyConfigured
 from django.core.urlresolvers import reverse
 from django.test import SimpleTestCase, TestCase, override_settings
 from django.test.client import RequestFactory
-from django.utils.deprecation import RemovedInDjango110Warning
 from django.views.generic.base import View
 from django.views.generic.edit import CreateView, FormMixin, ModelFormMixin
 
@@ -59,28 +56,6 @@ class FormMixinTests(SimpleTestCase):
             'get_form() should fallback to get_form_class() if none is provided.'
         )
 
-    def test_get_form_missing_form_class_default_value(self):
-        with warnings.catch_warnings(record=True) as w:
-            warnings.filterwarnings('always')
-
-            class MissingDefaultValue(FormMixin):
-                request = RequestFactory().get('/')
-                form_class = forms.Form
-
-                def get_form(self, form_class):
-                    return form_class(**self.get_form_kwargs())
-        self.assertEqual(len(w), 1)
-        self.assertEqual(w[0].category, RemovedInDjango110Warning)
-        self.assertEqual(
-            str(w[0].message),
-            '`generic_views.test_edit.MissingDefaultValue.get_form` method '
-            'must define a default value for its `form_class` argument.'
-        )
-
-        self.assertIsInstance(
-            MissingDefaultValue().get_form(), forms.Form,
-        )
-
     def test_get_context_data(self):
         class FormContext(FormMixin):
             request = RequestFactory().get('/')