diff --git a/django/db/backends/base/base.py b/django/db/backends/base/base.py
index 2a0141fdab..a1b5b1db64 100644
--- a/django/db/backends/base/base.py
+++ b/django/db/backends/base/base.py
@@ -606,16 +606,21 @@ class BaseDatabaseWrapper:
if must_close:
self.close()
- @property
- def _nodb_connection(self):
+ @contextmanager
+ def _nodb_cursor(self):
"""
- Return an alternative connection to be used when there is no need to
- access the main database, specifically for test db creation/deletion.
- This also prevents the production database from being exposed to
- potential child threads while (or after) the test database is destroyed.
- Refs #10868, #17786, #16969.
+ Return a cursor from an alternative connection to be used when there is
+ no need to access the main database, specifically for test db
+ creation/deletion. This also prevents the production database from
+ being exposed to potential child threads while (or after) the test
+ database is destroyed. Refs #10868, #17786, #16969.
"""
- return self.__class__({**self.settings_dict, 'NAME': None}, alias=NO_DB_ALIAS)
+ conn = self.__class__({**self.settings_dict, 'NAME': None}, alias=NO_DB_ALIAS)
+ try:
+ with conn.cursor() as cursor:
+ yield cursor
+ finally:
+ conn.close()
def schema_editor(self, *args, **kwargs):
"""
diff --git a/django/db/backends/base/creation.py b/django/db/backends/base/creation.py
index dd3407bac3..c50fc90171 100644
--- a/django/db/backends/base/creation.py
+++ b/django/db/backends/base/creation.py
@@ -20,12 +20,8 @@ class BaseDatabaseCreation:
def __init__(self, connection):
self.connection = connection
- @property
- def _nodb_connection(self):
- """
- Used to be defined here, now moved to DatabaseWrapper.
- """
- return self.connection._nodb_connection
+ def _nodb_cursor(self):
+ return self.connection._nodb_cursor()
def log(self, msg):
sys.stderr.write(msg + os.linesep)
@@ -166,7 +162,7 @@ class BaseDatabaseCreation:
'suffix': self.sql_table_creation_suffix(),
}
# Create the test database and connect to it.
- with self._nodb_connection.cursor() as cursor:
+ with self._nodb_cursor() as cursor:
try:
self._execute_create_test_db(cursor, test_db_params, keepdb)
except Exception as e:
@@ -272,7 +268,7 @@ class BaseDatabaseCreation:
# ourselves. Connect to the previous database (not the test database)
# to do so, because it's not allowed to delete a database while being
# connected to it.
- with self.connection._nodb_connection.cursor() as cursor:
+ with self._nodb_cursor() as cursor:
cursor.execute("DROP DATABASE %s"
% self.connection.ops.quote_name(test_database_name))
diff --git a/django/db/backends/mysql/creation.py b/django/db/backends/mysql/creation.py
index c9330819e5..79d2959d5f 100644
--- a/django/db/backends/mysql/creation.py
+++ b/django/db/backends/mysql/creation.py
@@ -35,7 +35,7 @@ class DatabaseCreation(BaseDatabaseCreation):
'dbname': self.connection.ops.quote_name(target_database_name),
'suffix': self.sql_table_creation_suffix(),
}
- with self._nodb_connection.cursor() as cursor:
+ with self._nodb_cursor() as cursor:
try:
self._execute_create_test_db(cursor, test_db_params, keepdb)
except Exception:
diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 12b969142e..0f45ca93e1 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -7,6 +7,7 @@ Requires psycopg 2: https://www.psycopg.org/
import asyncio
import threading
import warnings
+from contextlib import contextmanager
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
@@ -288,11 +289,11 @@ class DatabaseWrapper(BaseDatabaseWrapper):
else:
return True
- @property
- def _nodb_connection(self):
- nodb_connection = super()._nodb_connection
+ @contextmanager
+ def _nodb_cursor(self):
try:
- nodb_connection.ensure_connection()
+ with super()._nodb_cursor() as cursor:
+ yield cursor
except (Database.DatabaseError, WrappedDatabaseError):
warnings.warn(
"Normally Django will use a connection to the 'postgres' database "
@@ -304,11 +305,15 @@ class DatabaseWrapper(BaseDatabaseWrapper):
)
for connection in connections.all():
if connection.vendor == 'postgresql' and connection.settings_dict['NAME'] != 'postgres':
- return self.__class__(
+ conn = self.__class__(
{**self.settings_dict, 'NAME': connection.settings_dict['NAME']},
alias=self.alias,
)
- return nodb_connection
+ try:
+ with conn.cursor() as cursor:
+ yield cursor
+ finally:
+ conn.close()
@cached_property
def pg_version(self):
diff --git a/django/db/backends/postgresql/creation.py b/django/db/backends/postgresql/creation.py
index 0cb26a4341..a609f33fd6 100644
--- a/django/db/backends/postgresql/creation.py
+++ b/django/db/backends/postgresql/creation.py
@@ -61,7 +61,7 @@ class DatabaseCreation(BaseDatabaseCreation):
'dbname': self._quote_name(target_database_name),
'suffix': self._get_database_create_suffix(template=source_database_name),
}
- with self._nodb_connection.cursor() as cursor:
+ with self._nodb_cursor() as cursor:
try:
self._execute_create_test_db(cursor, test_db_params, keepdb)
except Exception:
diff --git a/docs/releases/3.1.txt b/docs/releases/3.1.txt
index 903e2510ba..58fed5080a 100644
--- a/docs/releases/3.1.txt
+++ b/docs/releases/3.1.txt
@@ -386,6 +386,11 @@ backends.
on databases that support time zones. Previously, it was ``None`` on
databases that support time zones.
+* ``connection._nodb_connection`` property is changed to the
+ ``connection._nodb_cursor()`` method and now returns a context manager that
+ yields a cursor and automatically closes the cursor and connection upon
+ exiting the ``with`` statement.
+
Dropped support for MariaDB 10.1
--------------------------------
diff --git a/tests/backends/postgresql/tests.py b/tests/backends/postgresql/tests.py
index 4e51c1c7b5..ab8ad4bb93 100644
--- a/tests/backends/postgresql/tests.py
+++ b/tests/backends/postgresql/tests.py
@@ -4,24 +4,32 @@ from unittest import mock
from django.core.exceptions import ImproperlyConfigured
from django.db import DatabaseError, connection, connections
+from django.db.backends.base.base import BaseDatabaseWrapper
from django.test import TestCase, override_settings
@unittest.skipUnless(connection.vendor == 'postgresql', 'PostgreSQL tests')
class Tests(TestCase):
+ databases = {'default', 'other'}
- def test_nodb_connection(self):
+ def test_nodb_cursor(self):
"""
- The _nodb_connection property fallbacks to the default connection
- database when access to the 'postgres' database is not granted.
+ The _nodb_cursor() fallbacks to the default connection database when
+ access to the 'postgres' database is not granted.
"""
+ orig_connect = BaseDatabaseWrapper.connect
+
def mocked_connect(self):
if self.settings_dict['NAME'] is None:
raise DatabaseError()
- return ''
+ return orig_connect(self)
- nodb_conn = connection._nodb_connection
- self.assertIsNone(nodb_conn.settings_dict['NAME'])
+ with connection._nodb_cursor() as cursor:
+ self.assertIs(cursor.closed, False)
+ self.assertIsNotNone(cursor.db.connection)
+ self.assertIsNone(cursor.db.settings_dict['NAME'])
+ self.assertIs(cursor.closed, True)
+ self.assertIsNone(cursor.db.connection)
# Now assume the 'postgres' db isn't available
msg = (
@@ -39,9 +47,13 @@ class Tests(TestCase):
'settings_dict',
{**connection.settings_dict, 'NAME': 'postgres'},
):
- nodb_conn = connection._nodb_connection
- self.assertIsNotNone(nodb_conn.settings_dict['NAME'])
- self.assertEqual(nodb_conn.settings_dict['NAME'], connections['other'].settings_dict['NAME'])
+ with connection._nodb_cursor() as cursor:
+ self.assertIs(cursor.closed, False)
+ self.assertIsNotNone(cursor.db.connection)
+ self.assertIs(cursor.closed, True)
+ self.assertIsNone(cursor.db.connection)
+ self.assertIsNotNone(cursor.db.settings_dict['NAME'])
+ self.assertEqual(cursor.db.settings_dict['NAME'], connections['other'].settings_dict['NAME'])
def test_database_name_too_long(self):
from django.db.backends.postgresql.base import DatabaseWrapper
diff --git a/tests/postgres_tests/test_signals.py b/tests/postgres_tests/test_signals.py
index 3c6502b5e7..f1569c361c 100644
--- a/tests/postgres_tests/test_signals.py
+++ b/tests/postgres_tests/test_signals.py
@@ -38,4 +38,5 @@ class OIDTests(PostgreSQLTestCase):
def test_register_type_handlers_no_db(self):
"""Registering type handlers for the nodb connection does nothing."""
- register_type_handlers(connection._nodb_connection)
+ with connection._nodb_cursor() as cursor:
+ register_type_handlers(cursor.db)