return item

pynamodb/connection/base.py

@@ -357,6 +357,7 @@ def _make_api_call(self, operation_name: str, operation_kwargs: Dict) -> Dict:
                         CancellationReason(
                             code=d['Code'],
                             message=d.get('Message'),
+                            item=d.get('Item'),
                         ) if d['Code'] != 'None' else None
                     )
                     for d in cancellation_reasons

pynamodb/exceptions.py

@@ -134,6 +134,7 @@ class CancellationReason:
     """
     code: str
     message: Optional[str] = None
+    item: Optional[Dict[str, Any]] = None
 
 
 class TransactWriteError(PynamoDBException):

tests/integration/test_transaction_integration.py

@@ -5,6 +5,7 @@
 import pytest
 
 from pynamodb.connection import Connection
+from pynamodb.constants import ALL_OLD
 from pynamodb.exceptions import CancellationReason
 from pynamodb.exceptions import DoesNotExist, TransactWriteError, InvalidStateError
 
@@ -168,6 +169,24 @@ def test_transact_write__error__transaction_cancelled__condition_check_failure(c
     assert BankStatement.Meta.table_name in exc_info.value.cause.MSG_TEMPLATE
 
 
+@pytest.mark.ddblocal
+def test_transact_write__error__transaction_cancelled__condition_check_failure__return_all_old(connection):
+    # create a users and a bank statements for them
+    User(1).save()
+
+    # attempt to do this as a transaction with the condition that they don't already exist
+    with pytest.raises(TransactWriteError) as exc_info:
+        with TransactWrite(connection=connection) as transaction:
+            transaction.save(User(1), condition=(User.user_id.does_not_exist()), return_values=ALL_OLD)
+    assert exc_info.value.cause_response_code == TRANSACTION_CANCELLED
+    assert 'ConditionalCheckFailed' in exc_info.value.cause_response_message
+    assert exc_info.value.cancellation_reasons == [
+        CancellationReason(code='ConditionalCheckFailed', message='The conditional request failed', item=User(1).to_dynamodb_dict()),
+    ]
+    assert isinstance(exc_info.value.cause, botocore.exceptions.ClientError)
+    assert User.Meta.table_name in exc_info.value.cause.MSG_TEMPLATE
+
+
 @pytest.mark.ddblocal
 def test_transact_write__error__transaction_cancelled__partial_failure(connection):
     User(2).delete()