Fixed #21134 -- Prevented queries in broken transactions.

Squashed commit of the following:

commit 63ddb271a44df389b2c302e421fc17b7f0529755
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Sun Sep 29 22:51:00 2013 +0200

    Clarified interactions between atomic and exceptions.

commit 2899ec299228217c876ba3aa4024e523a41c8504
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Sun Sep 22 22:45:32 2013 +0200

    Fixed TransactionManagementError in tests.

    Previous commit introduced an additional check to prevent running
    queries in transactions that will be rolled back, which triggered a few
    failures in the tests. In practice using transaction.atomic instead of
    the low-level savepoint APIs was enough to fix the problems.

commit 4a639b059ea80aeb78f7f160a7d4b9f609b9c238
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Tue Sep 24 22:24:17 2013 +0200

    Allowed nesting constraint_checks_disabled inside atomic.

    Since MySQL handles transactions loosely, this isn't a problem.

commit 2a4ab1cb6e83391ff7e25d08479e230ca564bfef
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Sat Sep 21 18:43:12 2013 +0200

    Prevented running queries in transactions that will be rolled back.

    This avoids a counter-intuitive behavior in an edge case on databases
    with non-atomic transaction semantics.

    It prevents using savepoint_rollback() inside an atomic block without
    calling set_rollback(False) first, which is backwards-incompatible in
    tests.

    Refs #21134.

commit 8e3db393853c7ac64a445b66e57f3620a3fde7b0
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Sun Sep 22 22:14:17 2013 +0200

    Replaced manual savepoints by atomic blocks.

    This ensures the rollback flag is handled consistently in internal APIs.

5 files changed, 70 insertions, 51 deletions

diff --git a/tests/custom_pk/tests.py b/tests/custom_pk/tests.py
index a452561edb..22369747a9 100644
--- a/tests/custom_pk/tests.py
+++ b/tests/custom_pk/tests.py
@@ -149,11 +149,9 @@ class CustomPKTests(TestCase):
         Employee.objects.create(
             employee_code=123, first_name="Frank", last_name="Jones"
         )
-        sid = transaction.savepoint()
-        self.assertRaises(IntegrityError,
-            Employee.objects.create, employee_code=123, first_name="Fred", last_name="Jones"
-        )
-        transaction.savepoint_rollback(sid)
+        with self.assertRaises(IntegrityError):
+            with transaction.atomic():
+                Employee.objects.create(employee_code=123, first_name="Fred", last_name="Jones")
 
     def test_custom_field_pk(self):
         # Regression for #10785 -- Custom fields can be used for primary keys.
@@ -175,8 +173,6 @@ class CustomPKTests(TestCase):
     def test_required_pk(self):
         # The primary key must be specified, so an error is raised if you
         # try to create an object without it.
-        sid = transaction.savepoint()
-        self.assertRaises(IntegrityError,
-            Employee.objects.create, first_name="Tom", last_name="Smith"
-        )
-        transaction.savepoint_rollback(sid)
+        with self.assertRaises(IntegrityError):
+            with transaction.atomic():
+                Employee.objects.create(first_name="Tom", last_name="Smith")
diff --git a/tests/expressions/tests.py b/tests/expressions/tests.py
index 9801d0acbb..a24c2fbc10 100644
--- a/tests/expressions/tests.py
+++ b/tests/expressions/tests.py
@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 from django.core.exceptions import FieldError
 from django.db.models import F
+from django.db import transaction
 from django.test import TestCase
 from django.utils import six
 
@@ -185,11 +186,11 @@ class ExpressionsTests(TestCase):
             "foo",
         )
 
-        self.assertRaises(FieldError,
-            lambda: Company.objects.exclude(
-                ceo__firstname=F('point_of_contact__firstname')
-            ).update(name=F('point_of_contact__lastname'))
-        )
+        with transaction.atomic():
+            with self.assertRaises(FieldError):
+                Company.objects.exclude(
+                    ceo__firstname=F('point_of_contact__firstname')
+                ).update(name=F('point_of_contact__lastname'))
 
         # F expressions can be used to update attributes on single objects
         test_gmbh = Company.objects.get(name="Test GmbH")
diff --git a/tests/force_insert_update/tests.py b/tests/force_insert_update/tests.py
index 706a099872..6d87151d83 100644
--- a/tests/force_insert_update/tests.py
+++ b/tests/force_insert_update/tests.py
@@ -21,24 +21,29 @@ class ForceTests(TestCase):
         # Won't work because force_update and force_insert are mutually
         # exclusive
         c.value = 4
-        self.assertRaises(ValueError, c.save, force_insert=True, force_update=True)
+        with self.assertRaises(ValueError):
+            c.save(force_insert=True, force_update=True)
 
         # Try to update something that doesn't have a primary key in the first
         # place.
         c1 = Counter(name="two", value=2)
-        self.assertRaises(ValueError, c1.save, force_update=True)
+        with self.assertRaises(ValueError):
+            with transaction.atomic():
+                c1.save(force_update=True)
         c1.save(force_insert=True)
 
         # Won't work because we can't insert a pk of the same value.
-        sid = transaction.savepoint()
         c.value = 5
-        self.assertRaises(IntegrityError, c.save, force_insert=True)
-        transaction.savepoint_rollback(sid)
+        with self.assertRaises(IntegrityError):
+            with transaction.atomic():
+                c.save(force_insert=True)
 
         # Trying to update should still fail, even with manual primary keys, if
         # the data isn't in the database already.
         obj = WithCustomPK(name=1, value=1)
-        self.assertRaises(DatabaseError, obj.save, force_update=True)
+        with self.assertRaises(DatabaseError):
+            with transaction.atomic():
+                obj.save(force_update=True)
 
 
 class InheritanceTests(TestCase):
diff --git a/tests/one_to_one/tests.py b/tests/one_to_one/tests.py
index 6e16d81cea..45a72f0df8 100644
--- a/tests/one_to_one/tests.py
+++ b/tests/one_to_one/tests.py
@@ -118,7 +118,7 @@ class OneToOneTests(TestCase):
         self.assertEqual(repr(o1.multimodel), '<MultiModel: Multimodel x1>')
         # This will fail because each one-to-one field must be unique (and
         # link2=o1 was used for x1, above).
-        sid = transaction.savepoint()
         mm = MultiModel(link1=self.p2, link2=o1, name="x1")
-        self.assertRaises(IntegrityError, mm.save)
-        transaction.savepoint_rollback(sid)
+        with self.assertRaises(IntegrityError):
+            with transaction.atomic():
+                mm.save()
diff --git a/tests/transactions/tests.py b/tests/transactions/tests.py
index 70a77b719e..0cef7a545b 100644
--- a/tests/transactions/tests.py
+++ b/tests/transactions/tests.py
@@ -4,7 +4,7 @@ import sys
 from unittest import skipIf, skipUnless
 
 from django.db import connection, transaction, DatabaseError, IntegrityError
-from django.test import TransactionTestCase, skipUnlessDBFeature
+from django.test import TransactionTestCase, skipIfDBFeature, skipUnlessDBFeature
 from django.test.utils import IgnoreDeprecationWarningsMixin
 from django.utils import six
 
@@ -204,10 +204,10 @@ class AtomicTests(TransactionTestCase):
                 with transaction.atomic(savepoint=False):
                     connection.cursor().execute(
                             "SELECT no_such_col FROM transactions_reporter")
-            transaction.savepoint_rollback(sid)
-            # atomic block should rollback, but prevent it, as we just did it.
+            # 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>'])
 
 
@@ -267,11 +267,19 @@ class AtomicMergeTests(TransactionTestCase):
                     with transaction.atomic(savepoint=False):
                         Reporter.objects.create(first_name="Calculus")
                         raise Exception("Oops, that's his last name")
-                # It wasn't possible to roll back
+                # 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)
-            # It wasn't possible to roll back
+                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)
-        # The outer block must roll back
+            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):
@@ -283,36 +291,22 @@ class AtomicMergeTests(TransactionTestCase):
                     with transaction.atomic(savepoint=False):
                         Reporter.objects.create(first_name="Calculus")
                         raise Exception("Oops, that's his last name")
-                # It wasn't possible to roll back
+                # 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)
-            # The first block with a savepoint must roll back
+                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>'])
 
-    def test_merged_outer_rollback_after_inner_failure_and_inner_success(self):
-        with transaction.atomic():
-            Reporter.objects.create(first_name="Tintin")
-            # Inner block without a savepoint fails
-            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")
-            # It wasn't possible to roll back
-            self.assertEqual(Reporter.objects.count(), 2)
-            # Inner block with a savepoint succeeds
-            with transaction.atomic(savepoint=False):
-                Reporter.objects.create(first_name="Archibald", last_name="Haddock")
-            # It still wasn't possible to roll back
-            self.assertEqual(Reporter.objects.count(), 3)
-        # The outer block must rollback
-        self.assertQuerysetEqual(Reporter.objects.all(), [])
-
 
 @skipUnless(connection.features.uses_savepoints,
         "'atomic' requires transactions and savepoints.")
 class AtomicErrorsTests(TransactionTestCase):
 
-    available_apps = []
+    available_apps = ['transactions']
 
     def test_atomic_prevents_setting_autocommit(self):
         autocommit = transaction.get_autocommit()
@@ -336,6 +330,29 @@ class AtomicErrorsTests(TransactionTestCase):
             with self.assertRaises(transaction.TransactionManagementError):
                 transaction.leave_transaction_management()
 
+    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")
+
 
 class AtomicMiscTests(TransactionTestCase):