Fixed #36318 -- Fixed incorrect rollback exception attribution in nested atomic blocks.

Signed-off-by: saJaeHyukc <wogur981208@gmail.com>

django/db/transaction.py

@@ -195,6 +195,7 @@ class Atomic(ContextDecorator):
             # Reset state when entering an outermost atomic block.
             connection.commit_on_exit = True
             connection.needs_rollback = False
+            connection.rollback_exc = None
             if not connection.get_autocommit():
                 # Pretend we're already in an atomic block to bypass the code
                 # that disables autocommit to enter a transaction, and make a
@@ -278,6 +279,9 @@ class Atomic(ContextDecorator):
                     # otherwise.
                     if sid is None:
                         connection.needs_rollback = True
+                        # Avoid shadowing an already assigned rollback exc.
+                        if connection.rollback_exc is None:
+                            connection.rollback_exc = exc_value
                     else:
                         try:
                             connection.savepoint_rollback(sid)

tests/transactions/tests.py

@@ -359,6 +359,28 @@ class AtomicErrorsTests(TransactionTestCase):
         self.assertIsInstance(cm.exception.__cause__, IntegrityError)
         self.assertEqual(Reporter.objects.get(pk=r1.pk).last_name, "Haddock")
 
+    def test_atomic_prevents_queries_in_broken_transaction_cause_attribution(self):
+        # Trigger a previous atomic rollback to populate cause.
+        with self.assertRaises(Exception), transaction.atomic():
+            raise Exception("First failure")
+
+        with (
+            self.assertRaises(transaction.TransactionManagementError) as ctx,
+            transaction.atomic(),
+        ):
+            try:
+                with transaction.atomic(savepoint=False):
+                    raise Exception("Second failure")
+            except Exception:
+                pass
+            try:
+                with transaction.atomic(savepoint=False):
+                    raise Exception("Third failure")
+            except Exception:
+                pass
+            Reporter.objects.count()
+        self.assertEqual(str(ctx.exception.__cause__), "Second failure")
+
     @skipIfDBFeature("atomic_transactions")
     def test_atomic_allows_queries_after_fixing_transaction(self):
         r1 = Reporter.objects.create(first_name="Archibald", last_name="Haddock")