Use decomposition instead of Operator.expand

pennylane_lightning/core/_serialize.py

@@ -404,7 +404,7 @@
                 uses_stateprep = True
                 continue
             if isinstance(operation, Rot):
-                op_list = operation.expand().operations
+                op_list = operation.decomposition()
             else:
                 op_list = [operation]
 

pennylane_lightning/core/_version.py

@@ -16,4 +16,4 @@
    Version number (major.minor.patch[-label])
 """
 
-__version__ = "0.38.0-dev28"
+__version__ = "0.38.0-dev29"

tests/test_serialize.py

@@ -740,6 +740,29 @@ def test_basic_circuit(self, wires_map):
         )
         assert s == s_expected
 
+    @pytest.mark.parametrize("wires_map", [wires_dict, None])
+    def test_Rot_in_circuit(self, wires_map):
+        """Test expected serialization for a circuit with Rot which should be decomposed"""
+
+        with qml.queuing.AnnotatedQueue() as q:
+            qml.Rot(0.1, 0.2, 0.3, wires=0)
+
+        tape = qml.tape.QuantumScript.from_queue(q)
+        s = QuantumScriptSerializer(device_name).serialize_ops(tape, wires_map)
+        s_expected = (
+            (
+                ["RZ", "RY", "RZ"],
+                [np.array([0.1]), np.array([0.2]), np.array([0.3])],
+                [[0], [0], [0]],
+                [False, False, False],
+                [[], [], []],
+                [[], [], []],
+                [[], [], []],
+            ),
+            False,
+        )
+        assert s == s_expected
+
     @pytest.mark.parametrize("wires_map", [wires_dict, None])
     def test_basic_circuit_not_implemented_ctrl_ops(self, wires_map):
         """Test expected serialization for a simple circuit"""