deprecation: change Circuit.to_ir default to OpenQASM, warn on JAQCD

src/braket/circuits/circuit.py

@@ -13,6 +13,7 @@
 
 from __future__ import annotations
 
+import warnings
 from collections import Counter
 from collections.abc import Callable, Iterable, Sequence
 from numbers import Number
@@ -1311,7 +1312,7 @@ def diagram(self, circuit_diagram_class: type = UnicodeCircuitDiagram) -> str:
 
     def to_ir(
         self,
-        ir_type: IRType = IRType.JAQCD,
+        ir_type: IRType = IRType.OPENQASM,
         serialization_properties: SerializationProperties | None = None,
         gate_definitions: dict[tuple[Gate, QubitSet], PulseSequence] | None = None,
     ) -> OpenQasmProgram | JaqcdProgram:
@@ -1337,6 +1338,10 @@ def to_ir(
         """
         gate_definitions = gate_definitions or {}
         if ir_type == IRType.JAQCD:
+            warnings.warn(
+                "The JAQCD action type is deprecated. Please use OpenQASM 3 programs instead.",
+                stacklevel=2,
+            )
             return self._to_jaqcd()
         if ir_type == IRType.OPENQASM:
             if serialization_properties and not isinstance(

src/braket/devices/local_simulator.py

@@ -262,9 +262,6 @@ def _(self, circuit: Circuit, inputs: dict[str, float] | None, shots: int):
             program = circuit.to_ir(ir_type=IRType.OPENQASM)
             program.inputs.update(inputs or {})
             return program
-        if DeviceActionType.JAQCD in simulator.properties.action:
-            validate_circuit_and_shots(circuit, shots)
-            return circuit.to_ir(ir_type=IRType.JAQCD)
         raise NotImplementedError(f"{type(simulator)} does not support qubit gate-based programs")
 
     @_construct_payload.register

test/unit_tests/braket/circuits/test_circuit.py

@@ -1184,9 +1184,9 @@ def h_nested(target):
 
 def test_ir_empty_instructions_result_types():
     circ = Circuit()
-    assert circ.to_ir() == jaqcd.Program(
-        instructions=[], results=[], basis_rotation_instructions=[]
-    )
+    with pytest.warns(UserWarning, match="JAQCD"):
+        ir = circ.to_ir(IRType.JAQCD)
+    assert ir == jaqcd.Program(instructions=[], results=[], basis_rotation_instructions=[])
 
 
 def test_ir_non_empty_instructions_result_types():
@@ -1196,7 +1196,9 @@ def test_ir_non_empty_instructions_result_types():
         results=[jaqcd.Probability(targets=[0, 1])],
         basis_rotation_instructions=[],
     )
-    assert circ.to_ir() == expected
+    with pytest.warns(UserWarning, match="JAQCD"):
+        ir = circ.to_ir(IRType.JAQCD)
+    assert ir == expected
 
 
 def test_ir_non_empty_instructions_result_types_basis_rotation_instructions():
@@ -1206,7 +1208,16 @@ def test_ir_non_empty_instructions_result_types_basis_rotation_instructions():
         results=[jaqcd.Sample(observable=["x"], targets=[0])],
         basis_rotation_instructions=[jaqcd.H(target=0)],
     )
-    assert circ.to_ir() == expected
+    with pytest.warns(UserWarning, match="JAQCD"):
+        ir = circ.to_ir(IRType.JAQCD)
+    assert ir == expected
+
+
+def test_to_ir_default_is_openqasm():
+    """Calling Circuit.to_ir() with no ir_type argument should return an
+    OpenQASM program (after the JAQCD-deprecation default flip)."""
+    circ = Circuit().h(0).cnot(0, 1)
+    assert isinstance(circ.to_ir(), OpenQasmProgram)
 
 
 @pytest.mark.parametrize(
@@ -3815,5 +3826,8 @@ def test_barrier_openqasm_export_all_qubits():
 
 def test_barrier_jaqcd_export_fails():
     circ = Circuit().h(0).barrier([0, 1])
-    with pytest.raises(NotImplementedError, match="Barrier is not supported in JAQCD"):
+    with (
+        pytest.warns(UserWarning, match="JAQCD"),
+        pytest.raises(NotImplementedError, match="Barrier is not supported in JAQCD"),
+    ):
         circ.to_ir(IRType.JAQCD)

test/unit_tests/braket/devices/test_local_simulator.py

@@ -689,13 +689,11 @@ def test_run_program_model_inputs():
     assert task.result() == GateModelQuantumTaskResult.from_object(GATE_MODEL_RESULT)
 
 
-def test_run_jaqcd_only():
+def test_run_jaqcd_only_raises():
     dummy = DummyJaqcdSimulator()
     sim = LocalSimulator(dummy)
-    task = sim.run(Circuit().h(0).cnot(0, 1), 10)
-    dummy.assert_shots(10)
-    dummy.assert_qubits(None)
-    assert task.result() == GateModelQuantumTaskResult.from_object(GATE_MODEL_RESULT)
+    with pytest.raises(NotImplementedError, match="does not support qubit gate-based programs"):
+        sim.run(Circuit().h(0).cnot(0, 1), 10)
 
 
 def test_run_program_model():