From 0bce2f102c5734d0c7ff1ebf0b10a316d58ed5ce Mon Sep 17 00:00:00 2001
From: Berker Peksag <berker.peksag@gmail.com>
Date: Fri, 3 Jun 2016 12:55:30 -0700
Subject: [PATCH] Fixed #12810 -- Added a check for clashing
ManyToManyField.db_table names.
---
django/db/models/fields/related.py | 31 +++++++++++
docs/ref/checks.txt | 2 +
tests/invalid_models_tests/test_models.py | 66 +++++++++++++++++++++++
3 files changed, 99 insertions(+)
diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 4b8b1804b5..0639bf3d79 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -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.
diff --git a/docs/ref/checks.txt b/docs/ref/checks.txt
index 074a901de8..aff3bd2bdc 100644
--- a/docs/ref/checks.txt
+++ b/docs/ref/checks.txt
@@ -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
diff --git a/tests/invalid_models_tests/test_models.py b/tests/invalid_models_tests/test_models.py
index b8f15cae60..fa63b9e8a7 100644
--- a/tests/invalid_models_tests/test_models.py
+++ b/tests/invalid_models_tests/test_models.py
@@ -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',
+ )
+ ])