Commit 0bce2f10 authored by Berker Peksag's avatar Berker Peksag Committed by Tim Graham
Browse files

Fixed #12810 -- Added a check for clashing ManyToManyField.db_table names.

parent faeeb84e

django/db/models/fields/related.py

+31 −0
Original line number Diff line number Diff line
@@ -1194,6 +1194,7 @@ class ManyToManyField(RelatedField): 
        errors.extend(self._check_unique(**kwargs))

        errors.extend(self._check_relationship_model(**kwargs))

        errors.extend(self._check_ignored_options(**kwargs))

        errors.extend(self._check_table_uniqueness(**kwargs))

        return errors



    def _check_unique(self, **kwargs):
@@ -1429,6 +1430,36 @@ class ManyToManyField(RelatedField): 


        return errors



    def _check_table_uniqueness(self, **kwargs):

        if isinstance(self.remote_field.through, six.string_types):

            return []

        registered_tables = {

            model._meta.db_table: model

            for model in self.opts.apps.get_models(include_auto_created=True)

            if model != self.remote_field.through

        }

        m2m_db_table = self.m2m_db_table()

        if m2m_db_table in registered_tables:

            model = registered_tables[m2m_db_table]

            if model._meta.auto_created:

                def _get_field_name(model):

                    for field in model._meta.auto_created._meta.many_to_many:

                        if field.remote_field.through is model:

                            return field.name

                opts = model._meta.auto_created._meta

                clashing_obj = '%s.%s' % (opts.label, _get_field_name(model))

            else:

                clashing_obj = '%s' % model._meta.label

            return [

                checks.Error(

                    "The field's intermediary table '%s' clashes with the "

                    "table name of '%s'." % (m2m_db_table, clashing_obj),

                    obj=self,

                    id='fields.E340',

                )

            ]

        return []



    def deconstruct(self):

        name, path, args, kwargs = super(ManyToManyField, self).deconstruct()

        # Handle the simpler arguments.

docs/ref/checks.txt

+2 −0
Original line number Diff line number Diff line
@@ -245,6 +245,8 @@ Related Fields 
* **fields.E338**: The intermediary model ``<through model>`` has no field

  ``<field name>``.

* **fields.E339**: ``<model>.<field name>`` is not a foreign key to ``<model>``.

* **fields.E340**: The field's intermediary table ``<table name>`` clashes with

  the table name of ``<model>``/``<model>.<field name>``.

* **fields.W340**: ``null`` has no effect on ``ManyToManyField``.

* **fields.W341**: ``ManyToManyField`` does not support ``validators``.

* **fields.W342**: Setting ``unique=True`` on a ``ForeignKey`` has the same

tests/invalid_models_tests/test_models.py

+66 −0
Original line number Diff line number Diff line
@@ -761,3 +761,69 @@ class OtherModelTests(SimpleTestCase): 
            'as an implicit link is deprecated.'

        )

        self.assertEqual(ParkingLot._meta.pk.name, 'parent')



    def test_m2m_table_name_clash(self):

        class Foo(models.Model):

            bar = models.ManyToManyField('Bar', db_table='myapp_bar')



            class Meta:

                db_table = 'myapp_foo'



        class Bar(models.Model):

            class Meta:

                db_table = 'myapp_bar'



        self.assertEqual(Foo.check(), [

            Error(

                "The field's intermediary table 'myapp_bar' clashes with the "

                "table name of 'invalid_models_tests.Bar'.",

                obj=Foo._meta.get_field('bar'),

                id='fields.E340',

            )

        ])



    def test_m2m_field_table_name_clash(self):

        class Foo(models.Model):

            pass



        class Bar(models.Model):

            foos = models.ManyToManyField(Foo, db_table='clash')



        class Baz(models.Model):

            foos = models.ManyToManyField(Foo, db_table='clash')



        self.assertEqual(Bar.check() + Baz.check(), [

            Error(

                "The field's intermediary table 'clash' clashes with the "

                "table name of 'invalid_models_tests.Baz.foos'.",

                obj=Bar._meta.get_field('foos'),

                id='fields.E340',

            ),

            Error(

                "The field's intermediary table 'clash' clashes with the "

                "table name of 'invalid_models_tests.Bar.foos'.",

                obj=Baz._meta.get_field('foos'),

                id='fields.E340',

            )

        ])



    def test_m2m_autogenerated_table_name_clash(self):

        class Foo(models.Model):

            class Meta:

                db_table = 'bar_foos'



        class Bar(models.Model):

            # The autogenerated `db_table` will be bar_foos.

            foos = models.ManyToManyField(Foo)



            class Meta:

                db_table = 'bar'



        self.assertEqual(Bar.check(), [

            Error(

                "The field's intermediary table 'bar_foos' clashes with the "

                "table name of 'invalid_models_tests.Foo'.",

                obj=Bar._meta.get_field('foos'),

                id='fields.E340',

            )

        ])