django/tests/transactions/tests.py

from __future__ import unicode_literals

import sys
try:
    import threading
except ImportError:
    threading = None
import time
from unittest import skipIf, skipUnless

from django.db import (connection, transaction,
    DatabaseError, Error, IntegrityError, OperationalError)
from django.test import TransactionTestCase, skipIfDBFeature, skipUnlessDBFeature
from django.utils import six

from .models import Reporter


@skipUnless(connection.features.uses_savepoints,
        "'atomic' requires transactions and savepoints.")
class AtomicTests(TransactionTestCase):
    """
    Tests for the atomic decorator and context manager.

    The tests make assertions on internal attributes because there isn't a
    robust way to ask the database for its current transaction state.

    Since the decorator syntax is converted into a context manager (see the
    implementation), there are only a few basic tests with the decorator
    syntax and the bulk of the tests use the context manager syntax.
    """

    available_apps = ['transactions']

    def test_decorator_syntax_commit(self):
        @transaction.atomic
        def make_reporter():
            Reporter.objects.create(first_name="Tintin")
        make_reporter()
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])

    def test_decorator_syntax_rollback(self):
        @transaction.atomic
        def make_reporter():
            Reporter.objects.create(first_name="Haddock")
            raise Exception("Oops, that's his last name")
        with six.assertRaisesRegex(self, Exception, "Oops"):
            make_reporter()
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_alternate_decorator_syntax_commit(self):
        @transaction.atomic()
        def make_reporter():
            Reporter.objects.create(first_name="Tintin")
        make_reporter()
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])

    def test_alternate_decorator_syntax_rollback(self):
        @transaction.atomic()
        def make_reporter():
            Reporter.objects.create(first_name="Haddock")
            raise Exception("Oops, that's his last name")
        with six.assertRaisesRegex(self, Exception, "Oops"):
            make_reporter()
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_commit(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])

    def test_rollback(self):
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(first_name="Haddock")
                raise Exception("Oops, that's his last name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_nested_commit_commit(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with transaction.atomic():
                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
        self.assertQuerysetEqual(Reporter.objects.all(),
                ['<Reporter: Archibald Haddock>', '<Reporter: Tintin>'])

    def test_nested_commit_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with six.assertRaisesRegex(self, Exception, "Oops"):
                with transaction.atomic():
                    Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])

    def test_nested_rollback_commit(self):
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(last_name="Tintin")
                with transaction.atomic():
                    Reporter.objects.create(last_name="Haddock")
                raise Exception("Oops, that's his first name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_nested_rollback_rollback(self):
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(last_name="Tintin")
                with six.assertRaisesRegex(self, Exception, "Oops"):
                    with transaction.atomic():
                        Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
                raise Exception("Oops, that's his first name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_merged_commit_commit(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with transaction.atomic(savepoint=False):
                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
        self.assertQuerysetEqual(Reporter.objects.all(),
                ['<Reporter: Archibald Haddock>', '<Reporter: Tintin>'])

    def test_merged_commit_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with six.assertRaisesRegex(self, Exception, "Oops"):
                with transaction.atomic(savepoint=False):
                    Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
        # Writes in the outer block are rolled back too.
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_merged_rollback_commit(self):
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(last_name="Tintin")
                with transaction.atomic(savepoint=False):
                    Reporter.objects.create(last_name="Haddock")
                raise Exception("Oops, that's his first name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_merged_rollback_rollback(self):
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(last_name="Tintin")
                with six.assertRaisesRegex(self, Exception, "Oops"):
                    with transaction.atomic(savepoint=False):
                        Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
                raise Exception("Oops, that's his first name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_reuse_commit_commit(self):
        atomic = transaction.atomic()
        with atomic:
            Reporter.objects.create(first_name="Tintin")
            with atomic:
                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
        self.assertQuerysetEqual(Reporter.objects.all(),
                ['<Reporter: Archibald Haddock>', '<Reporter: Tintin>'])

    def test_reuse_commit_rollback(self):
        atomic = transaction.atomic()
        with atomic:
            Reporter.objects.create(first_name="Tintin")
            with six.assertRaisesRegex(self, Exception, "Oops"):
                with atomic:
                    Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])

    def test_reuse_rollback_commit(self):
        atomic = transaction.atomic()
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with atomic:
                Reporter.objects.create(last_name="Tintin")
                with atomic:
                    Reporter.objects.create(last_name="Haddock")
                raise Exception("Oops, that's his first name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_reuse_rollback_rollback(self):
        atomic = transaction.atomic()
        with six.assertRaisesRegex(self, Exception, "Oops"):
            with atomic:
                Reporter.objects.create(last_name="Tintin")
                with six.assertRaisesRegex(self, Exception, "Oops"):
                    with atomic:
                        Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
                raise Exception("Oops, that's his first name")
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_force_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            # atomic block shouldn't rollback, but force it.
            self.assertFalse(transaction.get_rollback())
            transaction.set_rollback(True)
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_prevent_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            sid = transaction.savepoint()
            # trigger a database error inside an inner atomic without savepoint
            with self.assertRaises(DatabaseError):
                with transaction.atomic(savepoint=False):
                    with connection.cursor() as cursor:
                        cursor.execute(
                            "SELECT no_such_col FROM transactions_reporter")
            # prevent atomic from rolling back since we're recovering manually
            self.assertTrue(transaction.get_rollback())
            transaction.set_rollback(False)
            transaction.savepoint_rollback(sid)
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])


class AtomicInsideTransactionTests(AtomicTests):
    """All basic tests for atomic should also pass within an existing transaction."""

    def setUp(self):
        self.atomic = transaction.atomic()
        self.atomic.__enter__()

    def tearDown(self):
        self.atomic.__exit__(*sys.exc_info())


@skipIf(connection.features.autocommits_when_autocommit_is_off,
        "This test requires a non-autocommit mode that doesn't autocommit.")
class AtomicWithoutAutocommitTests(AtomicTests):
    """All basic tests for atomic should also pass when autocommit is turned off."""

    def setUp(self):
        transaction.set_autocommit(False)

    def tearDown(self):
        # The tests access the database after exercising 'atomic', initiating
        # a transaction ; a rollback is required before restoring autocommit.
        transaction.rollback()
        transaction.set_autocommit(True)


@skipUnless(connection.features.uses_savepoints,
        "'atomic' requires transactions and savepoints.")
class AtomicMergeTests(TransactionTestCase):
    """Test merging transactions with savepoint=False."""

    available_apps = ['transactions']

    def test_merged_outer_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with transaction.atomic(savepoint=False):
                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
                with six.assertRaisesRegex(self, Exception, "Oops"):
                    with transaction.atomic(savepoint=False):
                        Reporter.objects.create(first_name="Calculus")
                        raise Exception("Oops, that's his last name")
                # The third insert couldn't be roll back. Temporarily mark the
                # connection as not needing rollback to check it.
                self.assertTrue(transaction.get_rollback())
                transaction.set_rollback(False)
                self.assertEqual(Reporter.objects.count(), 3)
                transaction.set_rollback(True)
            # The second insert couldn't be roll back. Temporarily mark the
            # connection as not needing rollback to check it.
            self.assertTrue(transaction.get_rollback())
            transaction.set_rollback(False)
            self.assertEqual(Reporter.objects.count(), 3)
            transaction.set_rollback(True)
        # The first block has a savepoint and must roll back.
        self.assertQuerysetEqual(Reporter.objects.all(), [])

    def test_merged_inner_savepoint_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with transaction.atomic():
                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
                with six.assertRaisesRegex(self, Exception, "Oops"):
                    with transaction.atomic(savepoint=False):
                        Reporter.objects.create(first_name="Calculus")
                        raise Exception("Oops, that's his last name")
                # The third insert couldn't be roll back. Temporarily mark the
                # connection as not needing rollback to check it.
                self.assertTrue(transaction.get_rollback())
                transaction.set_rollback(False)
                self.assertEqual(Reporter.objects.count(), 3)
                transaction.set_rollback(True)
            # The second block has a savepoint and must roll back.
            self.assertEqual(Reporter.objects.count(), 1)
        self.assertQuerysetEqual(Reporter.objects.all(), ['<Reporter: Tintin>'])


@skipUnless(connection.features.uses_savepoints,
        "'atomic' requires transactions and savepoints.")
class AtomicErrorsTests(TransactionTestCase):

    available_apps = ['transactions']

    def test_atomic_prevents_setting_autocommit(self):
        autocommit = transaction.get_autocommit()
        with transaction.atomic():
            with self.assertRaises(transaction.TransactionManagementError):
                transaction.set_autocommit(not autocommit)
        # Make sure autocommit wasn't changed.
        self.assertEqual(connection.autocommit, autocommit)

    def test_atomic_prevents_calling_transaction_methods(self):
        with transaction.atomic():
            with self.assertRaises(transaction.TransactionManagementError):
                transaction.commit()
            with self.assertRaises(transaction.TransactionManagementError):
                transaction.rollback()

    def test_atomic_prevents_queries_in_broken_transaction(self):
        r1 = Reporter.objects.create(first_name="Archibald", last_name="Haddock")
        with transaction.atomic():
            r2 = Reporter(first_name="Cuthbert", last_name="Calculus", id=r1.id)
            with self.assertRaises(IntegrityError):
                r2.save(force_insert=True)
            # The transaction is marked as needing rollback.
            with self.assertRaises(transaction.TransactionManagementError):
                r2.save(force_update=True)
        self.assertEqual(Reporter.objects.get(pk=r1.pk).last_name, "Haddock")

    @skipIfDBFeature('atomic_transactions')
    def test_atomic_allows_queries_after_fixing_transaction(self):
        r1 = Reporter.objects.create(first_name="Archibald", last_name="Haddock")
        with transaction.atomic():
            r2 = Reporter(first_name="Cuthbert", last_name="Calculus", id=r1.id)
            with self.assertRaises(IntegrityError):
                r2.save(force_insert=True)
            # Mark the transaction as no longer needing rollback.
            transaction.set_rollback(False)
            r2.save(force_update=True)
        self.assertEqual(Reporter.objects.get(pk=r1.pk).last_name, "Calculus")

    @skipUnlessDBFeature('test_db_allows_multiple_connections')
    def test_atomic_prevents_queries_in_broken_transaction_after_client_close(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Archibald", last_name="Haddock")
            connection.close()
            # The connection is closed and the transaction is marked as
            # needing rollback. This will raise an InterfaceError on databases
            # that refuse to create cursors on closed connections (PostgreSQL)
            # and a TransactionManagementError on other databases.
            with self.assertRaises(Error):
                Reporter.objects.create(first_name="Cuthbert", last_name="Calculus")
        # The connection is usable again .
        self.assertEqual(Reporter.objects.count(), 0)


@skipUnless(connection.vendor == 'mysql', "MySQL-specific behaviors")
class AtomicMySQLTests(TransactionTestCase):

    available_apps = ['transactions']

    @skipIf(threading is None, "Test requires threading")
    def test_implicit_savepoint_rollback(self):
        """MySQL implicitly rolls back savepoints when it deadlocks (#22291)."""

        other_thread_ready = threading.Event()

        def other_thread():
            try:
                with transaction.atomic():
                    Reporter.objects.create(id=1, first_name="Tintin")
                    other_thread_ready.set()
                    # We cannot synchronize the two threads with an event here
                    # because the main thread locks. Sleep for a little while.
                    time.sleep(1)
                    # 2) ... and this line deadlocks. (see below for 1)
                    Reporter.objects.exclude(id=1).update(id=2)
            finally:
                # This is the thread-local connection, not the main connection.
                connection.close()

        other_thread = threading.Thread(target=other_thread)
        other_thread.start()
        other_thread_ready.wait()

        with six.assertRaisesRegex(self, OperationalError, 'Deadlock found'):
            # Double atomic to enter a transaction and create a savepoint.
            with transaction.atomic():
                with transaction.atomic():
                    # 1) This line locks... (see above for 2)
                    Reporter.objects.create(id=1, first_name="Tintin")

        other_thread.join()


class AtomicMiscTests(TransactionTestCase):

    available_apps = []

    def test_wrap_callable_instance(self):
        # Regression test for #20028
        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

        # Expect an error when rolling back a savepoint that doesn't exist.
        # Done outside of the transaction block to ensure proper recovery.
        with self.assertRaises(Error):

            # Start a plain transaction.
            with transaction.atomic():

                # Swallow the intentional error raised in the sub-transaction.
                with six.assertRaisesRegex(self, Exception, "Oops"):

                    # Start a sub-transaction with a savepoint.
                    with transaction.atomic():
                        sid = connection.savepoint_ids[-1]
                        raise Exception("Oops")

                # This is expected to fail because the savepoint no longer exists.
                connection.savepoint_rollback(sid)