Fixed #27504 -- Allowed using the ORM after an error and rollback when autocommit is off.

django/db/backends/base/base.py

@@ -267,7 +267,7 @@ class BaseDatabaseWrapper(object):
         self._rollback()
         # A successful rollback means that the database connection works.
         self.errors_occurred = False
-
+        self.needs_rollback = False
         self.run_on_commit = []
 
     def close(self):

tests/transactions/tests.py

@@ -443,8 +443,28 @@ 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.")
+
+@skipIf(
+    connection.features.autocommits_when_autocommit_is_off,
+    "This test requires a non-autocommit mode that doesn't autocommit."
+)
+class NonAutocommitTests(TransactionTestCase):
+
+    available_apps = []
+
+    def test_orm_query_after_error_and_rollback(self):
+        """
+        ORM queries are allowed after an error and a rollback in non-autocommit
+        mode (#27504).
+        """
+        transaction.set_autocommit(False)
+        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)."""
         transaction.set_autocommit(False)