[Repo Assist] fix: preserve mediation confounders and no_directed_path in IdentifiedEstimand.__deepcopy__

dowhy/causal_identifier/identified_estimand.py

@@ -114,9 +114,12 @@ def __deepcopy__(self, memo):
             instrumental_variables=copy.deepcopy(self.instrumental_variables),
             frontdoor_variables=copy.deepcopy(self.frontdoor_variables),
             mediator_variables=copy.deepcopy(self.mediator_variables),
+            mediation_first_stage_confounders=copy.deepcopy(self.mediation_first_stage_confounders),
+            mediation_second_stage_confounders=copy.deepcopy(self.mediation_second_stage_confounders),
             default_backdoor_id=copy.deepcopy(self.default_backdoor_id),
             default_adjustment_set_id=copy.deepcopy(self.default_adjustment_set_id),
             identifier_method=copy.deepcopy(self.identifier_method),
+            no_directed_path=self.no_directed_path,
         )
 
     def __str__(self, only_target_estimand: bool = False, show_all_backdoor_sets: bool = False):

tests/causal_identifiers/test_auto_identifier.py

@@ -1,3 +1,5 @@
+import copy
+
 from dowhy.causal_identifier import AutoIdentifier
 from dowhy.causal_identifier.identify_effect import EstimandType
 from dowhy.graph import build_graph_from_str
@@ -15,3 +17,33 @@ def test_auto_identify_identifies_no_directed_path(self):
         assert identifier.identify_effect(
             graph, action_nodes=["B", "T"], outcome_nodes=["Y"], observed_nodes=["T", "Y", "A", "B"]
         ).no_directed_path
+
+    def test_deepcopy_preserves_all_fields(self):
+        """Regression test: __deepcopy__ must copy mediation confounders and no_directed_path."""
+        # Build NDE estimand with mediation confounders
+        graph = build_graph_from_str("digraph{T->M;T->Y;M->Y;W->T;W->Y;}")
+        identifier = AutoIdentifier(estimand_type=EstimandType.NONPARAMETRIC_NDE)
+        estimand = identifier.identify_effect(
+            graph,
+            action_nodes=["T"],
+            outcome_nodes=["Y"],
+            observed_nodes=["T", "M", "Y", "W"],
+        )
+        estimand_copy = copy.deepcopy(estimand)
+
+        assert estimand_copy.mediator_variables == estimand.mediator_variables
+        assert estimand_copy.mediation_first_stage_confounders == estimand.mediation_first_stage_confounders
+        assert estimand_copy.mediation_second_stage_confounders == estimand.mediation_second_stage_confounders
+        assert estimand_copy.no_directed_path == estimand.no_directed_path
+
+    def test_deepcopy_preserves_no_directed_path_flag(self):
+        """Regression test: deepcopy of an estimand with no directed path preserves the flag."""
+        graph = build_graph_from_str("digraph{T->Y;A->Y;A->B;}")
+        identifier = AutoIdentifier(estimand_type=EstimandType.NONPARAMETRIC_ATE)
+        estimand = identifier.identify_effect(
+            graph, action_nodes=["T", "B"], outcome_nodes=["Y"], observed_nodes=["T", "Y", "A", "B"]
+        )
+        assert estimand.no_directed_path
+
+        estimand_copy = copy.deepcopy(estimand)
+        assert estimand_copy.no_directed_path