Commit 7549de84 authored by Claude Paroz's avatar Claude Paroz
Browse files

Fixed #18334 -- Fixed detection of supports_stddev backend feature. 

Thanks to Michael Manfre for the report and Anssi Kääriäinen for the
review.
parent 7495730d

django/db/backends/__init__.py

+7 −5
Original line number Diff line number Diff line
@@ -414,6 +414,7 @@ class BaseDatabaseFeatures(object): 


    def confirm(self):

        "Perform manual checks of any database features that might vary between installs"

        if not self._confirmed:

            self._confirmed = True

            self.supports_transactions = self._supports_transactions()

            self.supports_stddev = self._supports_stddev()
@@ -439,8 +440,9 @@ class BaseDatabaseFeatures(object): 


        try:

            self.connection.ops.check_aggregate_support(StdDevPop())

            return True

        except NotImplementedError:

            self.supports_stddev = False

            return False



    def _can_introspect_foreign_keys(self):

        "Confirm support for introspected foreign keys"

tests/regressiontests/backends/tests.py

+6 −0
Original line number Diff line number Diff line
@@ -397,6 +397,12 @@ class BackendTestCase(TestCase): 
        self.assertTrue(hasattr(connection.ops, 'connection'))

        self.assertEqual(connection, connection.ops.connection)



    def test_supports_needed_confirm(self):

        connection.features.confirm()

        self.assertIn(connection.features.supports_transactions, (True, False))

        self.assertIn(connection.features.supports_stddev, (True, False))

        self.assertIn(connection.features.can_introspect_foreign_keys, (True, False))



    def test_duplicate_table_error(self):

        """ Test that creating an existing table returns a DatabaseError """

        cursor = connection.cursor()