Deprecate device.qubit_set in cirq_google. (quantumlib#4940)

Yet more of quantumlib#4744 .

It also looks like now we can get rid of the device shim @mpharrigan , @dstrain115 (will leave to seperate PR).

cirq-google/cirq_google/devices/serializable_device.py

@@ -128,6 +128,10 @@ def metadata(self) -> cirq.GridDeviceMetadata:
         """Get metadata information for device."""
         return self._metadata
 
+    @_compat.deprecated(
+        fix='Please use metadata.qubit_set if applicable.',
+        deadline='v0.15',
+    )
     def qubit_set(self) -> FrozenSet[cirq.Qid]:
         return frozenset(self.qubits)
 

cirq-google/cirq_google/devices/serializable_device_test.py

@@ -133,6 +133,14 @@ def test_gate_definition_equality():
     eq.add_equality_group(cirq.X)
 
 
+def test_qubit_set_deprecated():
+    foxtail = cg.SerializableDevice.from_proto(
+        proto=cg.devices.known_devices.FOXTAIL_PROTO, gate_sets=[cg.XMON]
+    )
+    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
+        _ = foxtail.qubit_set()
+
+
 def test_foxtail():
     valid_qubit1 = cirq.GridQubit(0, 0)
     valid_qubit2 = cirq.GridQubit(1, 0)
@@ -143,7 +151,7 @@ def test_foxtail():
     foxtail = cg.SerializableDevice.from_proto(
         proto=cg.devices.known_devices.FOXTAIL_PROTO, gate_sets=[cg.XMON]
     )
-    assert foxtail.qubit_set() == frozenset(cirq.GridQubit.rect(2, 11, 0, 0))
+    assert foxtail.metadata.qubit_set == frozenset(cirq.GridQubit.rect(2, 11, 0, 0))
     foxtail.validate_operation(cirq.X(valid_qubit1))
     foxtail.validate_operation(cirq.X(valid_qubit2))
     foxtail.validate_operation(cirq.X(valid_qubit3))

cirq-google/cirq_google/devices/xmon_device.py

@@ -63,6 +63,10 @@ def metadata(self) -> cirq.GridDeviceMetadata:
         """Return the metadata for this device"""
         return self._metadata
 
+    @_compat.deprecated(
+        fix='Use metadata.qubit_set if applicable.',
+        deadline='v0.15',
+    )
     def qubit_set(self) -> FrozenSet[cirq.GridQubit]:
         return self.qubits
 

cirq-google/cirq_google/devices/xmon_device_test.py

@@ -73,6 +73,13 @@ def test_device_metadata():
     )
 
 
+@mock.patch.dict(os.environ, clear='CIRQ_TESTING')
+def test_qubit_set_deprecated():
+    d = square_device(2, 2)
+    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
+        _ = d.qubit_set()
+
+
 @mock.patch.dict(os.environ, clear='CIRQ_TESTING')
 def test_init():
     d = square_device(2, 2, holes=[cirq.GridQubit(1, 1)])

cirq-google/cirq_google/engine/virtual_engine_factory.py

@@ -64,9 +64,9 @@
 
 def _create_perfect_calibration(device: cirq.Device) -> calibration.Calibration:
     all_metrics: calibration.ALL_METRICS = {}
-    qubit_set = device.qubit_set()
-    if qubit_set is None:
+    if device.metadata is None:
         raise ValueError('Devices for noiseless Virtual Engine must have qubits')
+    qubit_set = device.metadata.qubit_set
     qubits = [cast(cirq.GridQubit, q) for q in qubit_set]
     for name in METRICS_1Q:
         all_metrics[name] = {(q,): [0.0] for q in qubits}

cirq-google/cirq_google/workflow/_device_shim.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import itertools
-from typing import Iterable, cast
+from typing import Iterable
 
 import cirq
 import networkx as nx
@@ -27,4 +27,6 @@ def _gridqubits_to_graph_device(qubits: Iterable[cirq.GridQubit]):
 
 def _Device_dot_get_nx_graph(device: 'cirq.Device') -> nx.Graph:
     """Shim over future `cirq.Device` method to get a NetworkX graph."""
-    return _gridqubits_to_graph_device(cast(Iterable[cirq.GridQubit], device.qubit_set()))
+    if device.metadata is not None:
+        return device.metadata.nx_graph
+    raise ValueError('Supplied device must contain metadata.')

cirq-google/cirq_google/workflow/qubit_placement_test.py

@@ -22,6 +22,12 @@
 class TestDevice(cirq.Device):
     def __init__(self):
         self.qubits = cirq.GridQubit.rect(2, 8)
+        neighbors = [(a, b) for a in self.qubits for b in self.qubits if a.is_adjacent(b)]
+        self._metadata = cirq.GridDeviceMetadata(neighbors, cirq.Gateset(cirq.H))
+
+    @property
+    def metadata(self):
+        return self._metadata
 
 
 def test_naive_qubit_placer():
@@ -31,7 +37,7 @@ def test_naive_qubit_placer():
         qubits, depth=8, two_qubit_op_factory=lambda a, b, _: cirq.SQRT_ISWAP(a, b)
     )
 
-    assert all(q in cg.Sycamore23.qubit_set() for q in circuit.all_qubits())
+    assert all(q in cg.Sycamore23.metadata.qubit_set for q in circuit.all_qubits())
 
     qp = cg.NaiveQubitPlacer()
     circuit2, mapping = qp.place_circuit(
@@ -42,7 +48,7 @@ def test_naive_qubit_placer():
     )
     assert circuit is not circuit2
     assert circuit == circuit2
-    assert all(q in cg.Sycamore23.qubit_set() for q in circuit2.all_qubits())
+    assert all(q in cg.Sycamore23.metadata.qubit_set for q in circuit2.all_qubits())
     for k, v in mapping.items():
         assert k == v
 
@@ -53,7 +59,7 @@ def test_random_device_placer_tilted_square_lattice():
     circuit = cirq.experiments.random_rotations_between_grid_interaction_layers_circuit(
         qubits, depth=8, two_qubit_op_factory=lambda a, b, _: cirq.SQRT_ISWAP(a, b)
     )
-    assert not all(q in cg.Sycamore23.qubit_set() for q in circuit.all_qubits())
+    assert not all(q in cg.Sycamore23.metadata.qubit_set for q in circuit.all_qubits())
 
     qp = cg.RandomDevicePlacer()
     circuit2, mapping = qp.place_circuit(
@@ -64,7 +70,7 @@ def test_random_device_placer_tilted_square_lattice():
     )
     assert circuit is not circuit2
     assert circuit != circuit2
-    assert all(q in cg.Sycamore23.qubit_set() for q in circuit2.all_qubits())
+    assert all(q in cg.Sycamore23.metadata.qubit_set for q in circuit2.all_qubits())
     for k, v in mapping.items():
         assert k != v
 
@@ -83,7 +89,7 @@ def test_random_device_placer_line():
     )
     assert circuit is not circuit2
     assert circuit != circuit2
-    assert all(q in cg.Sycamore23.qubit_set() for q in circuit2.all_qubits())
+    assert all(q in cg.Sycamore23.metadata.qubit_set for q in circuit2.all_qubits())
     for k, v in mapping.items():
         assert k != v
 
@@ -120,3 +126,22 @@ def test_random_device_placer_small_device():
             shared_rt_info=cg.SharedRuntimeInfo(run_id='1', device=TestDevice()),
             rs=np.random.RandomState(1),
         )
+
+
+def test_device_missing_metadata():
+    class BadDevice(cirq.Device):
+        pass
+
+    topo = cirq.TiltedSquareLattice(3, 3)
+    qubits = sorted(topo.nodes_to_gridqubits().values())
+    circuit = cirq.experiments.random_rotations_between_grid_interaction_layers_circuit(
+        qubits, depth=8, two_qubit_op_factory=lambda a, b, _: cirq.SQRT_ISWAP(a, b)
+    )
+    qp = cg.RandomDevicePlacer()
+    with pytest.raises(ValueError):
+        qp.place_circuit(
+            circuit,
+            problem_topology=topo,
+            shared_rt_info=cg.SharedRuntimeInfo(run_id='1', device=BadDevice()),
+            rs=np.random.RandomState(1),
+        )