Fixed #12667. Added optgroup validation support to model fields with choices. Thanks ramiro.

import datetime

import decimal

import os

import re

import time

import django.utils.copycompat as copy

from django.db import connection

from django.db.models import signals

from django.db.models.fields.subclassing import LegacyConnection

from django.db.models.query_utils import QueryWrapper

from django.dispatch import dispatcher

from django.conf import settings

from django import forms

from django.core import exceptions, validators

from django.utils.functional import curry

from django.utils.itercompat import tee

from django.utils.text import capfirst

from django.utils.translation import ugettext_lazy as _, ugettext

from django.utils.translation import ugettext_lazy as _

from django.utils.encoding import smart_unicode, force_unicode, smart_str

from django.utils import datetime_safe

            # Skip validation for non-editable fields.

            return

        if self._choices and value:

            if not value in dict(self.choices):

            for option_key, option_value in self.choices:

                if type(option_value) in (tuple, list):

                    # This is an optgroup, so look inside the group for options.

                    for optgroup_key, optgroup_value in option_value:

                        if value == optgroup_key:

                            return

                elif value == option_key:

                    return

            raise exceptions.ValidationError(self.error_messages['invalid_choice'] % value)

        if value is None and not self.null:

        f = models.CharField(choices=[('a','A'), ('b','B')])

        self.assertRaises(ValidationError, f.clean, "not a", None)

    def test_choices_validation_supports_named_groups(self):

        f = models.IntegerField(choices=(('group',((10,'A'),(20,'B'))),(30,'C')))

        self.assertEqual(10, f.clean(10, None))

    def test_nullable_integerfield_raises_error_with_blank_false(self):

        f = models.IntegerField(null=True, blank=False)

        self.assertRaises(ValidationError, f.clean, None, None)