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

1 files changed, 66 insertions, 0 deletions

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',
+            )
+        ])