From 7549de841c6e0d18822af047763f5e3211539be8 Mon Sep 17 00:00:00 2001 From: Claude Paroz Date: Fri, 18 May 2012 12:08:36 +0200 Subject: [PATCH] Fixed #18334 -- Fixed detection of supports_stddev backend feature. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Thanks to Michael Manfre for the report and Anssi Kääriäinen for the review. --- django/db/backends/__init__.py | 12 +++++++----- tests/regressiontests/backends/tests.py | 6 ++++++ 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py index 27623505e5..bf622b9a0f 100644 --- a/django/db/backends/__init__.py +++ b/django/db/backends/__init__.py @@ -414,10 +414,11 @@ class BaseDatabaseFeatures(object): def confirm(self): "Perform manual checks of any database features that might vary between installs" - self._confirmed = True - self.supports_transactions = self._supports_transactions() - self.supports_stddev = self._supports_stddev() - self.can_introspect_foreign_keys = self._can_introspect_foreign_keys() + if not self._confirmed: + self._confirmed = True + self.supports_transactions = self._supports_transactions() + self.supports_stddev = self._supports_stddev() + self.can_introspect_foreign_keys = self._can_introspect_foreign_keys() def _supports_transactions(self): "Confirm support for transactions" @@ -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" diff --git a/tests/regressiontests/backends/tests.py b/tests/regressiontests/backends/tests.py index eec817c5a2..10e69b65c1 100644 --- a/tests/regressiontests/backends/tests.py +++ b/tests/regressiontests/backends/tests.py @@ -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()