Remove qubit_set v0.15 deprecation. (quantumlib#5304)

Yet more v0.15 deprecation removals.

cirq-core/cirq/devices/device.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import abc
-from typing import TYPE_CHECKING, Optional, AbstractSet, FrozenSet, Iterable
+from typing import TYPE_CHECKING, Optional, FrozenSet, Iterable
 import networkx as nx
 from cirq import _compat, value
 
@@ -24,31 +24,6 @@
 class Device(metaclass=abc.ABCMeta):
     """Hardware constraints for validating circuits."""
 
-    @_compat.deprecated(fix='Use metadata.qubit_set if applicable.', deadline='v0.15')
-    def qubit_set(self) -> Optional[AbstractSet['cirq.Qid']]:
-        """Returns a set or frozenset of qubits on the device, if possible.
-
-        Returns:
-            If the device has a finite set of qubits, then a set or frozen set
-            of all qubits on the device is returned.
-
-            If the device has no well defined finite set of qubits (e.g.
-            `cirq.UnconstrainedDevice` has this property), then `None` is
-            returned.
-        """
-
-        # Compatibility hack to work with devices that were written before this
-        # method was defined.
-        for name in ['qubits', '_qubits']:
-            if hasattr(self, name):
-                val = getattr(self, name)
-                if callable(val):
-                    val = val()
-                return frozenset(val)
-
-        # Default to the qubits being unknown.
-        return None
-
     @_compat.deprecated(deadline='v0.15', fix='Devices will no longer decompose operations.')
     def decompose_operation(self, operation: 'cirq.Operation') -> 'cirq.OP_TREE':
         """Returns a device-valid decomposition for the given operation.

cirq-core/cirq/devices/device_test.py

@@ -3,42 +3,6 @@
 import cirq
 
 
-def test_qubit_set_deprecated():
-    class RawDevice(cirq.Device):
-        pass
-
-    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
-        assert RawDevice().qubit_set() is None
-
-    class QubitFieldDevice(cirq.Device):
-        def __init__(self):
-            self.qubits = cirq.LineQubit.range(3)
-
-    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
-        assert QubitFieldDevice().qubit_set() == frozenset(cirq.LineQubit.range(3))
-
-    class PrivateQubitFieldDevice(cirq.Device):
-        def __init__(self):
-            self._qubits = cirq.LineQubit.range(4)
-
-    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
-        assert PrivateQubitFieldDevice().qubit_set() == frozenset(cirq.LineQubit.range(4))
-
-    class QubitMethodDevice(cirq.Device):
-        def qubits(self):
-            return cirq.LineQubit.range(5)
-
-    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
-        assert QubitMethodDevice().qubit_set() == frozenset(cirq.LineQubit.range(5))
-
-    class PrivateQubitMethodDevice(cirq.Device):
-        def _qubits(self):
-            return cirq.LineQubit.range(6)
-
-    with cirq.testing.assert_deprecated('qubit_set', deadline='v0.15'):
-        assert PrivateQubitMethodDevice().qubit_set() == frozenset(cirq.LineQubit.range(6))
-
-
 def test_decompose_operation_deprecated():
     q0 = cirq.GridQubit(0, 0)