Fixed #24921 -- set_autocommit(False) + ORM queries.

This commits lifts the restriction that the outermost atomic block must
be declared with savepoint=False. This restriction was overly cautious.

The logic that makes it safe not to create savepoints for inner blocks
also applies to the outermost block when autocommit is disabled and a
transaction is already active.

This makes it possible to use the ORM after set_autocommit(False).
Previously it didn't work because ORM write operations are protected
with atomic(savepoint=False).
This commit is contained in:
Aymeric Augustin 2015-09-21 20:53:10 +02:00
parent 361254810e
commit 91e9f1c972
4 changed files with 25 additions and 11 deletions

View File

@ -164,13 +164,6 @@ class Atomic(ContextDecorator):
raise TransactionManagementError(
"Your database backend doesn't behave properly when "
"autocommit is off. Turn it on before using 'atomic'.")
# When entering an atomic block with autocommit turned off,
# Django should only use savepoints and shouldn't commit.
# This requires at least a savepoint for the outermost block.
if not self.savepoint:
raise TransactionManagementError(
"The outermost 'atomic' block cannot use "
"savepoint = False when autocommit is off.")
# Pretend we're already in an atomic block to bypass the code
# that disables autocommit to enter a transaction, and make a
# note to deal with this case in __exit__.

View File

@ -46,3 +46,7 @@ Bugfixes
* Readded inline foreign keys to form instances when validating model formsets
(:ticket:`25431`).
* Allowed using ORM write methods after disabling autocommit with
:func:`set_autocommit(False) <django.db.transaction.set_autocommit>`
(:ticket:`24921`).

View File

@ -200,8 +200,12 @@ Django provides a single API to control database transactions.
the error handling described above.
You may use ``atomic`` when autocommit is turned off. It will only use
savepoints, even for the outermost block, and it will raise an exception
if the outermost block is declared with ``savepoint=False``.
savepoints, even for the outermost block.
.. versionchanged:: 1.8.5
Previously the outermost atomic block couldn't be declared with
``savepoint=False`` when autocommit was turned off.
.. admonition:: Performance considerations

View File

@ -398,16 +398,18 @@ class AtomicMiscTests(TransactionTestCase):
available_apps = []
def test_wrap_callable_instance(self):
# Regression test for #20028
"""#20028 -- Atomic must support wrapping callable instances."""
class Callable(object):
def __call__(self):
pass
# Must not raise an exception
transaction.atomic(Callable())
@skipUnlessDBFeature('can_release_savepoints')
def test_atomic_does_not_leak_savepoints_on_failure(self):
# Regression test for #23074
"""#23074 -- Savepoints must be released after rollback."""
# Expect an error when rolling back a savepoint that doesn't exist.
# Done outside of the transaction block to ensure proper recovery.
@ -426,3 +428,14 @@ class AtomicMiscTests(TransactionTestCase):
# This is expected to fail because the savepoint no longer exists.
connection.savepoint_rollback(sid)
@skipIf(connection.features.autocommits_when_autocommit_is_off,
"This test requires a non-autocommit mode that doesn't autocommit.")
def test_orm_query_without_autocommit(self):
"""#24921 -- ORM queries must be possible after set_autocommit(False)."""
transaction.set_autocommit(False)
try:
Reporter.objects.create(first_name="Tintin")
finally:
transaction.rollback()
transaction.set_autocommit(True)