django/tests/transactions/tests.py

import sys
import threading
import time
from unittest import skipIf, skipUnless

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

from .models import Reporter


@skipUnlessDBFeature("uses_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():
            return Reporter.objects.create(first_name="Tintin")

        reporter = make_reporter()
        self.assertSequenceEqual(Reporter.objects.all(), [reporter])

    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 self.assertRaisesMessage(Exception, "Oops"):
            make_reporter()
        self.assertSequenceEqual(Reporter.objects.all(), [])

    def test_alternate_decorator_syntax_commit(self):
        @transaction.atomic()
        def make_reporter():
            return Reporter.objects.create(first_name="Tintin")

        reporter = make_reporter()
        self.assertSequenceEqual(Reporter.objects.all(), [reporter])

    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 self.assertRaisesMessage(Exception, "Oops"):
            make_reporter()
        self.assertSequenceEqual(Reporter.objects.all(), [])

    def test_commit(self):
        with transaction.atomic():
            reporter = Reporter.objects.create(first_name="Tintin")
        self.assertSequenceEqual(Reporter.objects.all(), [reporter])

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

    def test_nested_commit_commit(self):
        with transaction.atomic():
            reporter1 = Reporter.objects.create(first_name="Tintin")
            with transaction.atomic():
                reporter2 = Reporter.objects.create(
                    first_name="Archibald", last_name="Haddock"
                )
        self.assertSequenceEqual(Reporter.objects.all(), [reporter2, reporter1])

    def test_nested_commit_rollback(self):
        with transaction.atomic():
            reporter = Reporter.objects.create(first_name="Tintin")
            with self.assertRaisesMessage(Exception, "Oops"):
                with transaction.atomic():
                    Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
        self.assertSequenceEqual(Reporter.objects.all(), [reporter])

    def test_nested_rollback_commit(self):
        with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_nested_rollback_rollback(self):
        with self.assertRaisesMessage(Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(last_name="Tintin")
                with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_merged_commit_commit(self):
        with transaction.atomic():
            reporter1 = Reporter.objects.create(first_name="Tintin")
            with transaction.atomic(savepoint=False):
                reporter2 = Reporter.objects.create(
                    first_name="Archibald", last_name="Haddock"
                )
        self.assertSequenceEqual(Reporter.objects.all(), [reporter2, reporter1])

    def test_merged_commit_rollback(self):
        with transaction.atomic():
            Reporter.objects.create(first_name="Tintin")
            with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_merged_rollback_commit(self):
        with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_merged_rollback_rollback(self):
        with self.assertRaisesMessage(Exception, "Oops"):
            with transaction.atomic():
                Reporter.objects.create(last_name="Tintin")
                with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_reuse_commit_commit(self):
        atomic = transaction.atomic()
        with atomic:
            reporter1 = Reporter.objects.create(first_name="Tintin")
            with atomic:
                reporter2 = Reporter.objects.create(
                    first_name="Archibald", last_name="Haddock"
                )
        self.assertSequenceEqual(Reporter.objects.all(), [reporter2, reporter1])

    def test_reuse_commit_rollback(self):
        atomic = transaction.atomic()
        with atomic:
            reporter = Reporter.objects.create(first_name="Tintin")
            with self.assertRaisesMessage(Exception, "Oops"):
                with atomic:
                    Reporter.objects.create(first_name="Haddock")
                    raise Exception("Oops, that's his last name")
        self.assertSequenceEqual(Reporter.objects.all(), [reporter])

    def test_reuse_rollback_commit(self):
        atomic = transaction.atomic()
        with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_reuse_rollback_rollback(self):
        atomic = transaction.atomic()
        with self.assertRaisesMessage(Exception, "Oops"):
            with atomic:
                Reporter.objects.create(last_name="Tintin")
                with self.assertRaisesMessage(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.assertSequenceEqual(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_prevent_rollback(self):
        with transaction.atomic():
            reporter = 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.assertSequenceEqual(Reporter.objects.all(), [reporter])

    @skipUnlessDBFeature("can_release_savepoints")
    def test_failure_on_exit_transaction(self):
        with transaction.atomic():
            with self.assertRaises(DatabaseError):
                with transaction.atomic():
                    Reporter.objects.create(last_name="Tintin")
                    self.assertEqual(len(Reporter.objects.all()), 1)
                    # Incorrect savepoint id to provoke a database error.
                    connection.savepoint_ids.append("12")
            with self.assertRaises(transaction.TransactionManagementError):
                len(Reporter.objects.all())
            self.assertIs(connection.needs_rollback, True)
            if connection.savepoint_ids:
                connection.savepoint_ids.pop()
        self.assertSequenceEqual(Reporter.objects.all(), [])


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())


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)


@skipUnlessDBFeature("uses_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 self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [])

    def test_merged_inner_savepoint_rollback(self):
        with transaction.atomic():
            reporter = Reporter.objects.create(first_name="Tintin")
            with transaction.atomic():
                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
                with self.assertRaisesMessage(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.assertSequenceEqual(Reporter.objects.all(), [reporter])


@skipUnlessDBFeature("uses_savepoints")
class AtomicErrorsTests(TransactionTestCase):
    available_apps = ["transactions"]
    forbidden_atomic_msg = "This is forbidden when an 'atomic' block is active."

    def test_atomic_prevents_setting_autocommit(self):
        autocommit = transaction.get_autocommit()
        with transaction.atomic():
            with self.assertRaisesMessage(
                transaction.TransactionManagementError, self.forbidden_atomic_msg
            ):
                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.assertRaisesMessage(
                transaction.TransactionManagementError, self.forbidden_atomic_msg
            ):
                transaction.commit()
            with self.assertRaisesMessage(
                transaction.TransactionManagementError, self.forbidden_atomic_msg
            ):
                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.
            msg = (
                "An error occurred in the current transaction. You can't "
                "execute queries until the end of the 'atomic' block."
            )
            with self.assertRaisesMessage(
                transaction.TransactionManagementError, msg
            ) as cm:
                r2.save(force_update=True)
        self.assertIsInstance(cm.exception.__cause__, IntegrityError)
        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)


@skipUnlessDBFeature("uses_savepoints")
@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)."""
        Reporter.objects.create(id=1)
        Reporter.objects.create(id=2)

        main_thread_ready = threading.Event()

        def other_thread():
            try:
                with transaction.atomic():
                    Reporter.objects.select_for_update().get(id=1)
                    main_thread_ready.wait()
                    # 1) This line locks... (see below for 2)
                    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()

        with self.assertRaisesMessage(OperationalError, "Deadlock found"):
            # Double atomic to enter a transaction and create a savepoint.
            with transaction.atomic():
                with transaction.atomic():
                    Reporter.objects.select_for_update().get(id=2)
                    main_thread_ready.set()
                    # The two threads can't be synchronized with an event here
                    # because the other thread locks. Sleep for a little while.
                    time.sleep(1)
                    # 2) ... and this line deadlocks. (see above for 1)
                    Reporter.objects.exclude(id=2).update(id=1)

        other_thread.join()


class AtomicMiscTests(TransactionTestCase):
    available_apps = ["transactions"]

    def test_wrap_callable_instance(self):
        """#20028 -- Atomic must support wrapping callable instances."""

        class Callable:
            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):
        """#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.
        with self.assertRaises(Error):
            # Start a plain transaction.
            with transaction.atomic():
                # Swallow the intentional error raised in the sub-transaction.
                with self.assertRaisesMessage(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)

    def test_mark_for_rollback_on_error_in_transaction(self):
        with transaction.atomic(savepoint=False):
            # Swallow the intentional error raised.
            with self.assertRaisesMessage(Exception, "Oops"):
                # Wrap in `mark_for_rollback_on_error` to check if the
                # transaction is marked broken.
                with transaction.mark_for_rollback_on_error():
                    # Ensure that we are still in a good state.
                    self.assertFalse(transaction.get_rollback())

                    raise Exception("Oops")

                # mark_for_rollback_on_error marked the transaction as broken …
                self.assertTrue(transaction.get_rollback())

            # … and further queries fail.
            msg = "You can't execute queries until the end of the 'atomic' block."
            with self.assertRaisesMessage(transaction.TransactionManagementError, msg):
                Reporter.objects.create()

        # Transaction errors are reset at the end of an transaction, so this
        # should just work.
        Reporter.objects.create()

    def test_mark_for_rollback_on_error_in_autocommit(self):
        self.assertTrue(transaction.get_autocommit())

        # Swallow the intentional error raised.
        with self.assertRaisesMessage(Exception, "Oops"):
            # Wrap in `mark_for_rollback_on_error` to check if the transaction
            # is marked broken.
            with transaction.mark_for_rollback_on_error():
                # Ensure that we are still in a good state.
                self.assertFalse(transaction.get_connection().needs_rollback)

                raise Exception("Oops")

            # Ensure that `mark_for_rollback_on_error` did not mark the transaction
            # as broken, since we are in autocommit mode …
            self.assertFalse(transaction.get_connection().needs_rollback)

        # … and further queries work nicely.
        Reporter.objects.create()


class NonAutocommitTests(TransactionTestCase):
    available_apps = []

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

    def tearDown(self):
        transaction.rollback()
        transaction.set_autocommit(True)

    def test_orm_query_after_error_and_rollback(self):
        """
        ORM queries are allowed after an error and a rollback in non-autocommit
        mode (#27504).
        """
        r1 = Reporter.objects.create(first_name="Archibald", last_name="Haddock")
        r2 = Reporter(first_name="Cuthbert", last_name="Calculus", id=r1.id)
        with self.assertRaises(IntegrityError):
            r2.save(force_insert=True)
        transaction.rollback()
        Reporter.objects.last()

    def test_orm_query_without_autocommit(self):
        """#24921 -- ORM queries must be possible after set_autocommit(False)."""
        Reporter.objects.create(first_name="Tintin")


class DurableTestsBase:
    available_apps = ["transactions"]

    def test_commit(self):
        with transaction.atomic(durable=True):
            reporter = Reporter.objects.create(first_name="Tintin")
        self.assertEqual(Reporter.objects.get(), reporter)

    def test_nested_outer_durable(self):
        with transaction.atomic(durable=True):
            reporter1 = Reporter.objects.create(first_name="Tintin")
            with transaction.atomic():
                reporter2 = Reporter.objects.create(
                    first_name="Archibald",
                    last_name="Haddock",
                )
        self.assertSequenceEqual(Reporter.objects.all(), [reporter2, reporter1])

    def test_nested_both_durable(self):
        msg = "A durable atomic block cannot be nested within another atomic block."
        with transaction.atomic(durable=True):
            with self.assertRaisesMessage(RuntimeError, msg):
                with transaction.atomic(durable=True):
                    pass

    def test_nested_inner_durable(self):
        msg = "A durable atomic block cannot be nested within another atomic block."
        with transaction.atomic():
            with self.assertRaisesMessage(RuntimeError, msg):
                with transaction.atomic(durable=True):
                    pass

    def test_sequence_of_durables(self):
        with transaction.atomic(durable=True):
            reporter = Reporter.objects.create(first_name="Tintin 1")
        self.assertEqual(Reporter.objects.get(first_name="Tintin 1"), reporter)
        with transaction.atomic(durable=True):
            reporter = Reporter.objects.create(first_name="Tintin 2")
        self.assertEqual(Reporter.objects.get(first_name="Tintin 2"), reporter)


class DurableTransactionTests(DurableTestsBase, TransactionTestCase):
    pass


class DurableTests(DurableTestsBase, TestCase):
    pass