DynamoDB: transact_write_items() should raise ValidationException when putting and deleting the same item (#7378)

moto/dynamodb/models/__init__.py

@@ -579,7 +579,11 @@ class DynamoDBBackend(BaseBackend):
                     item = item["Put"]
                     attrs = item["Item"]
                     table_name = item["TableName"]
-                    check_unicity(table_name, item)
+                    table = self.get_table(table_name)
+                    key = {table.hash_key_attr: attrs[table.hash_key_attr]}
+                    if table.range_key_attr is not None:
+                        key[table.range_key_attr] = attrs[table.range_key_attr]
+                    check_unicity(table_name, key)
                     condition_expression = item.get("ConditionExpression", None)
                     expression_attribute_names = item.get(
                         "ExpressionAttributeNames", None

tests/test_dynamodb/exceptions/test_dynamodb_transactions.py

@@ -46,6 +46,55 @@ def test_multiple_transactions_on_same_item():
     )
 
 
+@mock_aws
+def test_transact_write_items__put_and_delete_on_same_item():
+    schema = {
+        "KeySchema": [
+            {"AttributeName": "pk", "KeyType": "HASH"},
+            {"AttributeName": "sk", "KeyType": "RANGE"},
+        ],
+        "AttributeDefinitions": [
+            {"AttributeName": "pk", "AttributeType": "S"},
+            {"AttributeName": "sk", "AttributeType": "S"},
+        ],
+    }
+    dynamodb = boto3.client("dynamodb", region_name="us-east-1")
+    dynamodb.create_table(
+        TableName="test-table", BillingMode="PAY_PER_REQUEST", **schema
+    )
+
+    with pytest.raises(ClientError) as exc:
+        dynamodb.transact_write_items(
+            TransactItems=[
+                {
+                    "Put": {
+                        "TableName": "test-table",
+                        "Item": {
+                            "pk": {"S": "test-pk"},
+                            "sk": {"S": "test-sk"},
+                            "field": {"S": "test-field"},
+                        },
+                    }
+                },
+                {
+                    "Delete": {
+                        "TableName": "test-table",
+                        "Key": {
+                            "pk": {"S": "test-pk"},
+                            "sk": {"S": "test-sk"},
+                        },
+                    }
+                },
+            ]
+        )
+    err = exc.value.response["Error"]
+    assert err["Code"] == "ValidationException"
+    assert (
+        err["Message"]
+        == "Transaction request cannot include multiple operations on one item"
+    )
+
+
 @mock_aws
 def test_transact_write_items__too_many_transactions():
     schema = {

tests/test_dynamodb/test_dynamodb.py

@@ -3856,24 +3856,27 @@ def test_transact_write_items_conditioncheck_passes():
     dynamodb.create_table(
         TableName="test-table", BillingMode="PAY_PER_REQUEST", **table_schema
     )
-    # Insert an item without email address
+    # Insert an item with email address
-    dynamodb.put_item(TableName="test-table", Item={"id": {"S": "foo"}})
+    dynamodb.put_item(
-    # Put an email address, after verifying it doesn't exist yet
+        TableName="test-table",
+        Item={"id": {"S": "foo"}, "email_address": {"S": "foo@moto.com"}},
+    )
+    # Put a new item, after verifying the exising item also has email address
     dynamodb.transact_write_items(
         TransactItems=[
             {
                 "ConditionCheck": {
                     "Key": {"id": {"S": "foo"}},
                     "TableName": "test-table",
-                    "ConditionExpression": "attribute_not_exists(#e)",
+                    "ConditionExpression": "attribute_exists(#e)",
                     "ExpressionAttributeNames": {"#e": "email_address"},
                 }
             },
             {
                 "Put": {
                     "Item": {
-                        "id": {"S": "foo"},
+                        "id": {"S": "bar"},
-                        "email_address": {"S": "test@moto.com"},
+                        "email_address": {"S": "bar@moto.com"},
                     },
                     "TableName": "test-table",
                 }
@@ -3882,8 +3885,9 @@ def test_transact_write_items_conditioncheck_passes():
     )
     # Assert all are present
     items = dynamodb.scan(TableName="test-table")["Items"]
-    assert len(items) == 1
+    assert len(items) == 2
-    assert items[0] == {"email_address": {"S": "test@moto.com"}, "id": {"S": "foo"}}
+    assert items[0] == {"email_address": {"S": "foo@moto.com"}, "id": {"S": "foo"}}
+    assert items[1] == {"email_address": {"S": "bar@moto.com"}, "id": {"S": "bar"}}
 
 
 @mock_aws
@@ -3896,12 +3900,12 @@ def test_transact_write_items_conditioncheck_fails():
     dynamodb.create_table(
         TableName="test-table", BillingMode="PAY_PER_REQUEST", **table_schema
     )
-    # Insert an item with email address
+    # Insert an item without email address
     dynamodb.put_item(
         TableName="test-table",
-        Item={"id": {"S": "foo"}, "email_address": {"S": "test@moto.com"}},
+        Item={"id": {"S": "foo"}},
     )
-    # Try to put an email address, but verify whether it exists
+    # Try putting a new item, after verifying the exising item also has email address
     # ConditionCheck should fail
     with pytest.raises(ClientError) as ex:
         dynamodb.transact_write_items(
@@ -3910,15 +3914,15 @@ def test_transact_write_items_conditioncheck_fails():
                     "ConditionCheck": {
                         "Key": {"id": {"S": "foo"}},
                         "TableName": "test-table",
-                        "ConditionExpression": "attribute_not_exists(#e)",
+                        "ConditionExpression": "attribute_exists(#e)",
                         "ExpressionAttributeNames": {"#e": "email_address"},
                     }
                 },
                 {
                     "Put": {
                         "Item": {
-                            "id": {"S": "foo"},
+                            "id": {"S": "bar"},
-                            "email_address": {"S": "update@moto.com"},
+                            "email_address": {"S": "bar@moto.com"},
                         },
                         "TableName": "test-table",
                     }
@@ -3929,10 +3933,10 @@ def test_transact_write_items_conditioncheck_fails():
     assert ex.value.response["Error"]["Code"] == "TransactionCanceledException"
     assert ex.value.response["ResponseMetadata"]["HTTPStatusCode"] == 400
 
-    # Assert the original email address is still present
+    # Assert the original item is still present
     items = dynamodb.scan(TableName="test-table")["Items"]
     assert len(items) == 1
-    assert items[0] == {"email_address": {"S": "test@moto.com"}, "id": {"S": "foo"}}
+    assert items[0] == {"id": {"S": "foo"}}
 
 
 @mock_aws