[BUGFIX] V1 Validator shouldn't mutate user's result format dict (#10496

)

great_expectations/validator/v1_validator.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from copy import copy
 from functools import cached_property
 from typing import TYPE_CHECKING, Optional
 
@@ -125,9 +126,9 @@ def _validate_expectation_configs(
 
         runtime_configuration: dict
         if isinstance(self.result_format, ResultFormat):
-            runtime_configuration = {"result_format": self.result_format.value}
+            runtime_configuration = {"result_format": copy(self.result_format.value)}
         else:
-            runtime_configuration = {"result_format": self.result_format}
+            runtime_configuration = {"result_format": copy(self.result_format)}
 
         results = self._wrapped_validator.graph_validate(
             configurations=processed_expectation_configs,

tests/validator/test_v1_validator.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from copy import copy
 from pprint import pformat as pf
 from unittest import mock
 
@@ -140,6 +141,22 @@ def test_result_format_complete(validator: Validator, failing_expectation: Expec
     assert "unexpected_list" in result.result
 
 
+@pytest.mark.unit
+def test_v1_validator_doesnt_mutate_result_format(
+    validator: Validator, expectation_suite: ExpectationSuite
+):
+    """This test verifies a bugfix where the legacy Validator mutates a ResultFormat
+    dict provided by the user.
+    """
+    result_format_dict = {
+        "result_format": "COMPLETE",
+    }
+    backup_result_format_dict = copy(result_format_dict)
+    validator.result_format = result_format_dict
+    validator.validate_expectation_suite(expectation_suite=expectation_suite)
+    assert result_format_dict == backup_result_format_dict
+
+
 @pytest.mark.unit
 def test_validate_expectation_success(validator: Validator, passing_expectation: Expectation):
     result = validator.validate_expectation(passing_expectation)