Fixed #14217 -- Added validation for field name collision when using model inheritance.

    Ryan Niemeyer <https://profiles.google.com/ryan.niemeyer/about>

    Sam Newman <http://www.magpiebrain.com/>

    Sander Dijkhuis <sander.dijkhuis@gmail.com>

    Sarthak Mehrish <sarthakmeh03@gmail.com>

    schwank@gmail.com

    Scot Hacker <shacker@birdhouse.org>

    Scott Barr <scott@divisionbyzero.com.au>

                used_fields[f.attname] = f

        # Check that fields defined in the model don't clash with fields from

        # parents.

        # parents, including auto-generated fields like multi-table inheritance

        # child accessors.

        for parent in cls._meta.get_parent_list():

            for f in parent._meta.get_fields():

                if f not in used_fields:

                    used_fields[f.name] = f

        for f in cls._meta.local_fields:

            clash = used_fields.get(f.name) or used_fields.get(f.attname) or None

            # Note that we may detect clash between user-defined non-unique

class ShadowingFieldsTests(IsolatedModelsTestCase):

    def test_field_name_clash_with_child_accessor(self):

        class Parent(models.Model):

            pass

        class Child(Parent):

            child = models.CharField(max_length=100)

        errors = Child.check()

        expected = [

            Error(

                "The field 'child' clashes with the field "

                "'child' from model 'invalid_models_tests.parent'.",

                hint=None,

                obj=Child._meta.get_field('child'),

                id='models.E006',

            )

        ]

        self.assertEqual(errors, expected)

    def test_multiinheritance_clash(self):

        class Mother(models.Model):

            clash = models.IntegerField()