Replace fields with properties in ActOnArgs (quantumlib#5011)

xref quantumlib#4851 @95-martin-orion

cirq/sim/act_on_args.py

@@ -17,21 +17,23 @@
 import inspect
 from typing import (
     Any,
+    cast,
     Dict,
+    Iterator,
     List,
+    Mapping,
+    Optional,
+    Sequence,
     TypeVar,
     TYPE_CHECKING,
-    Sequence,
     Tuple,
-    cast,
-    Optional,
-    Iterator,
 )
 import warnings
 
 import numpy as np
 
 from cirq import ops, protocols, value
+from cirq._compat import deprecated
 from cirq.protocols.decompose_protocol import _try_decompose_into_operations_and_qubits
 from cirq.sim.operation_target import OperationTarget
 
@@ -74,7 +76,7 @@ def __init__(
         if qubits is None:
             qubits = ()
         self._set_qubits(qubits)
-        self.prng = prng
+        self._prng = prng
         self._classical_data = classical_data or value.ClassicalDataDictionaryStore(
             _records={
                 value.MeasurementKey.parse_serialized(k): [tuple(v)]
@@ -83,9 +85,33 @@ def __init__(
         )
         self._ignore_measurement_results = ignore_measurement_results
 
+    @property
+    def prng(self) -> np.random.RandomState:
+        return self._prng
+
+    @property
+    def qubit_map(self) -> Mapping['cirq.Qid', int]:
+        return self._qubit_map
+
+    @prng.setter  # type: ignore
+    @deprecated(
+        deadline="v0.15",
+        fix="The mutators of this class are deprecated, instantiate a new object instead.",
+    )
+    def prng(self, prng):
+        self._prng = prng
+
+    @qubit_map.setter  # type: ignore
+    @deprecated(
+        deadline="v0.15",
+        fix="The mutators of this class are deprecated, instantiate a new object instead.",
+    )
+    def qubit_map(self, qubit_map):
+        self._qubit_map = qubit_map
+
     def _set_qubits(self, qubits: Sequence['cirq.Qid']):
         self._qubits = tuple(qubits)
-        self.qubit_map = {q: i for i, q in enumerate(self.qubits)}
+        self._qubit_map = {q: i for i, q in enumerate(self.qubits)}
 
     def measure(self, qubits: Sequence['cirq.Qid'], key: str, invert_mask: Sequence[bool]):
         """Measures the qubits and records to `log_of_measurement_results`.
@@ -281,8 +307,7 @@ def swap(self, q1: 'cirq.Qid', q2: 'cirq.Qid', *, inplace=False):
         i2 = self.qubits.index(q2)
         qubits = list(args.qubits)
         qubits[i1], qubits[i2] = qubits[i2], qubits[i1]
-        args._qubits = tuple(qubits)
-        args.qubit_map = {q: i for i, q in enumerate(qubits)}
+        args._set_qubits(qubits)
         return args
 
     def rename(self, q1: 'cirq.Qid', q2: 'cirq.Qid', *, inplace=False):
@@ -309,8 +334,7 @@ def rename(self, q1: 'cirq.Qid', q2: 'cirq.Qid', *, inplace=False):
         i1 = self.qubits.index(q1)
         qubits = list(args.qubits)
         qubits[i1] = q2
-        args._qubits = tuple(qubits)
-        args.qubit_map = {q: i for i, q in enumerate(qubits)}
+        args._set_qubits(qubits)
         return args
 
     def __getitem__(self: TSelf, item: Optional['cirq.Qid']) -> TSelf:

cirq/sim/act_on_args_container.py

@@ -20,6 +20,7 @@
     Generic,
     Iterator,
     List,
+    Mapping,
     Optional,
     Sequence,
     Tuple,
@@ -30,6 +31,7 @@
 import numpy as np
 
 from cirq import ops, protocols, value
+from cirq._compat import deprecated
 from cirq.sim.operation_target import OperationTarget
 from cirq.sim.simulator import (
     TActOnArgs,
@@ -68,16 +70,40 @@ def __init__(
             classical_data: The shared classical data container for this
                 simulation.
         """
-        self.args = args
+        self._args = args
         self._qubits = tuple(qubits)
-        self.split_untangled_states = split_untangled_states
+        self._split_untangled_states = split_untangled_states
         self._classical_data = classical_data or value.ClassicalDataDictionaryStore(
             _records={
                 value.MeasurementKey.parse_serialized(k): [tuple(v)]
                 for k, v in (log_of_measurement_results or {}).items()
             }
         )
 
+    @property
+    def args(self) -> Mapping[Optional['cirq.Qid'], TActOnArgs]:
+        return self._args
+
+    @property
+    def split_untangled_states(self) -> bool:
+        return self._split_untangled_states
+
+    @args.setter  # type: ignore
+    @deprecated(
+        deadline="v0.15",
+        fix="The mutators of this class are deprecated, instantiate a new object instead.",
+    )
+    def args(self, args):
+        self._args = args
+
+    @split_untangled_states.setter  # type: ignore
+    @deprecated(
+        deadline="v0.15",
+        fix="The mutators of this class are deprecated, instantiate a new object instead.",
+    )
+    def split_untangled_states(self, split_untangled_states):
+        self._split_untangled_states = split_untangled_states
+
     def create_merged_state(self) -> TActOnArgs:
         if not self.split_untangled_states:
             return self.args[None]
@@ -104,8 +130,8 @@ def _act_on_fallback_(
             if args0 is args1:
                 args0.swap(q0, q1, inplace=True)
             else:
-                self.args[q0] = args1.rename(q1, q0, inplace=True)
-                self.args[q1] = args0.rename(q0, q1, inplace=True)
+                self._args[q0] = args1.rename(q1, q0, inplace=True)
+                self._args[q1] = args0.rename(q0, q1, inplace=True)
             return True
 
         # Go through the op's qubits and join any disparate ActOnArgs states
@@ -120,7 +146,7 @@ def _act_on_fallback_(
 
         # (Backfill the args map with the new value)
         for q in op_args.qubits:
-            self.args[q] = op_args
+            self._args[q] = op_args
 
         # Act on the args with the operation
         act_on_qubits = qubits if isinstance(action, ops.Gate) else None
@@ -134,11 +160,11 @@ def _act_on_fallback_(
             for q in qubits:
                 if op_args.allows_factoring:
                     q_args, op_args = op_args.factor((q,), validate=False)
-                    self.args[q] = q_args
+                    self._args[q] = q_args
 
             # (Backfill the args map with the new value)
             for q in op_args.qubits:
-                self.args[q] = op_args
+                self._args[q] = op_args
         return True
 
     def copy(self, deep_copy_buffers: bool = True) -> 'cirq.ActOnArgsContainer[TActOnArgs]':

cirq/sim/act_on_args_container_test.py

@@ -282,3 +282,17 @@ def test_act_on_gate_does_not_join():
     assert len(set(args.values())) == 3
     assert args[q0] is not args[q1]
     assert args[q0] is not args[None]
+
+
+def test_field_getters():
+    args = create_container(qs2)
+    assert args.args.keys() == set(qs2) | {None}
+    assert args.split_untangled_states
+
+
+def test_field_setters_deprecated():
+    args = create_container(qs2)
+    with cirq.testing.assert_deprecated(deadline='v0.15'):
+        args.args = {}
+    with cirq.testing.assert_deprecated(deadline='v0.15'):
+        args.split_untangled_states = False

cirq/sim/act_on_args_test.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 from typing import Sequence, Union
 
+import numpy as np
 import pytest
 
 import cirq
@@ -98,3 +99,17 @@ def test_on_copy_has_no_param():
     args = DummyArgs()
     with cirq.testing.assert_deprecated('deep_copy_buffers', deadline='0.15'):
         args.copy(False)
+
+
+def test_field_getters():
+    args = DummyArgs()
+    assert args.prng is np.random
+    assert args.qubit_map == {q: i for i, q in enumerate(cirq.LineQubit.range(2))}
+
+
+def test_field_setters_deprecated():
+    args = DummyArgs()
+    with cirq.testing.assert_deprecated(deadline='v0.15'):
+        args.prng = 0
+    with cirq.testing.assert_deprecated(deadline='v0.15'):
+        args.qubit_map = {}