Fix qubit filtering in BackendV2Converter with add_delay

qiskit/providers/backend_compat.py

@@ -64,8 +64,11 @@ def convert_to_target(
     target = None
     if custom_name_mapping is not None:
         name_mapping.update(custom_name_mapping)
+    faulty_qubits = set()
     # Parse from properties if it exsits
     if properties is not None:
+        if filter_faulty:
+            faulty_qubits = set(properties.faulty_qubits())
         qubit_properties = qubit_props_list_from_props(properties=properties)
         target = Target(num_qubits=configuration.n_qubits, qubit_properties=qubit_properties)
         # Parse instructions
@@ -137,9 +140,6 @@ def convert_to_target(
         target.acquire_alignment = configuration.timing_constraints.get("acquire_alignment")
     # If a pulse defaults exists use that as the source of truth
     if defaults is not None:
-        faulty_qubits = set()
-        if filter_faulty and properties is not None:
-            faulty_qubits = set(properties.faulty_qubits())
         inst_map = defaults.instruction_schedule_map
         for inst in inst_map.instructions:
             for qarg in inst_map.qubits_with_instruction(inst):
@@ -174,7 +174,8 @@ def convert_to_target(
                 )
     if add_delay and "delay" not in target:
         target.add_instruction(
-            name_mapping["delay"], {(bit,): None for bit in range(target.num_qubits)}
+            name_mapping["delay"],
+            {(bit,): None for bit in range(target.num_qubits) if bit not in faulty_qubits},
         )
     return target
 

test/python/providers/test_fake_backends.py

@@ -494,6 +494,27 @@ def test_filter_faulty_qubits_backend_v2_converter(self):
             for qarg in v2_backend.target.qargs:
                 self.assertNotIn(i, qarg)
 
+    def test_filter_faulty_qubits_backend_v2_converter_with_delay(self):
+        """Test faulty qubits in v2 conversion."""
+        backend = FakeWashington()
+        # Get properties dict to make it easier to work with the properties API
+        # is difficult to edit because of the multiple layers of nesting and
+        # different object types
+        props_dict = backend.properties().to_dict()
+        for i in range(62, 67):
+            non_operational = {
+                "date": datetime.datetime.utcnow(),
+                "name": "operational",
+                "unit": "",
+                "value": 0,
+            }
+            props_dict["qubits"][i].append(non_operational)
+        backend._properties = BackendProperties.from_dict(props_dict)
+        v2_backend = BackendV2Converter(backend, filter_faulty=True, add_delay=True)
+        for i in range(62, 67):
+            for qarg in v2_backend.target.qargs:
+                self.assertNotIn(i, qarg)
+
     def test_filter_faulty_qubits_and_gates_backend_v2_converter(self):
         """Test faulty gates and qubits."""
         backend = FakeWashington()