Apply new deprecation decorators to circuit folder (#9869) (#10099)

* Apply new deprecation decorators to circuit folder

* Fix what I can (blocked by production issues)

* Work around tests using bad production code

* Revert "Work around tests using bad production code"

This reverts commit 54f6ee8.

* Better fix for the deprecations

* Use QiskitTestCase ignore mechanism

* Review feedback

* Fix lint and test failure

(cherry picked from commit 5323d8f)

Co-authored-by: Eric Arellano <14852634+Eric-Arellano@users.noreply.github.com>

qiskit/circuit/bit.py

@@ -13,9 +13,9 @@
 """
 Quantum bit and Classical bit objects.
 """
-import warnings
 
 from qiskit.circuit.exceptions import CircuitError
+from qiskit.utils.deprecation import deprecate_func
 
 
 class Bit:
@@ -59,53 +59,47 @@ def __init__(self, register=None, index=None):
             self._repr = f"{self.__class__.__name__}({self._register}, {self._index})"
 
     @property
-    def register(self):
+    @deprecate_func(
+        is_property=True,
+        since="0.17",
+        additional_msg=(
+            "Instead, use :meth:`~qiskit.circuit.quantumcircuit.QuantumCircuit.find_bit` to find "
+            "all the containing registers within a circuit and the index of the bit within the "
+            "circuit."
+        ),
+    )
+    def register(self):  # pylint: disable=bad-docstring-quotes
         """Get the register of an old-style bit.
 
-        .. deprecated:: 0.17
-            Use :meth:`.QuantumCircuit.find_bit` instead.
-
         In modern Qiskit Terra (version 0.17+), bits are the fundamental object and registers are
         aliases to collections of bits.  A bit can be in many registers depending on the circuit, so
         a single containing register is no longer a property of a bit.  It is an error to access
         this attribute on bits that were not constructed as "owned" by a register."""
         if (self._register, self._index) == (None, None):
             raise CircuitError("Attempt to query register of a new-style Bit.")
 
-        warnings.warn(
-            "'Bit.register' is deprecated since Qiskit Terra 0.17 and will be removed "
-            "in a future release. Bits may be in more than one register. "
-            "Use 'QuantumCircuit.find_bit' to find all the containing registers within a circuit, "
-            "and the index of the bit within the circuit.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-
         return self._register
 
     @property
-    def index(self):
+    @deprecate_func(
+        is_property=True,
+        since="0.17",
+        additional_msg=(
+            "Instead, use :meth:`~qiskit.circuit.quantumcircuit.QuantumCircuit.find_bit` to find "
+            "all the containing registers within a circuit and the index of the bit within the "
+            "circuit."
+        ),
+    )
+    def index(self):  # pylint: disable=bad-docstring-quotes
         """Get the index of an old-style bit in the register that owns it.
 
-        .. deprecated:: 0.17
-            Use :meth:`.QuantumCircuit.find_bit` instead.
-
         In modern Qiskit Terra (version 0.17+), bits are the fundamental object and registers are
         aliases to collections of bits.  A bit can be in many registers depending on the circuit, so
         a single containing register is no longer a property of a bit.  It is an error to access
         this attribute on bits that were not constructed as "owned" by a register."""
         if (self._register, self._index) == (None, None):
             raise CircuitError("Attempt to query index of a new-style Bit.")
 
-        warnings.warn(
-            "'Bit.index' is deprecated since Qiskit Terra 0.17 and will be removed "
-            "in a future release. Bits may be in more than one register. "
-            "Use 'QuantumCircuit.find_bit' to find all the containing registers within a circuit, "
-            "and the index of the bit within the circuit.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-
         return self._index
 
     def __repr__(self):

qiskit/circuit/classicalregister.py

@@ -19,8 +19,7 @@
 
 from qiskit.circuit.exceptions import CircuitError
 
-# Over-specific import to avoid cyclic imports.
-from qiskit.utils.deprecation import deprecate_function
+from qiskit.utils.deprecation import deprecate_func
 from .register import Register
 from .bit import Bit
 
@@ -58,10 +57,12 @@ class ClassicalRegister(Register):
     prefix = "c"
     bit_type = Clbit
 
-    @deprecate_function(
-        "Register.qasm() is deprecated since Terra 0.23, as correct exporting to OpenQASM 2 is "
-        "the responsibility of a larger exporter; it cannot safely be done on an object-by-object "
-        "basis without context. No replacement will be provided, because the premise is wrong.",
+    @deprecate_func(
+        additional_msg=(
+            "Correct exporting to OpenQASM 2 is the responsibility of a larger exporter; it cannot "
+            "safely be done on an object-by-object basis without context. No replacement will be "
+            "provided, because the premise is wrong."
+        ),
         since="0.23.0",
     )
     def qasm(self):

qiskit/circuit/instructionset.py

@@ -16,10 +16,10 @@
 
 from __future__ import annotations
 import functools
-import warnings
 from typing import Callable
 
 from qiskit.circuit.exceptions import CircuitError
+from qiskit.utils.deprecation import deprecate_arg
 from .classicalregister import Clbit, ClassicalRegister
 from .operation import Operation
 from .quantumcircuitdata import CircuitInstruction
@@ -95,7 +95,17 @@ class InstructionSet:
 
     __slots__ = ("_instructions", "_requester")
 
-    def __init__(
+    @deprecate_arg(
+        "circuit_cregs",
+        since="0.19.0",
+        additional_msg=(
+            "Instead, pass a complete resource requester with the 'resource_requester' argument. "
+            "The classical registers are insufficient to access all classical resources in a "
+            "circuit, as there may be loose classical bits as well. It can also cause integer "
+            "indices to be resolved incorrectly if any registers overlap."
+        ),
+    )
+    def __init__(  # pylint: disable=bad-docstring-quotes
         self,
         circuit_cregs: list[ClassicalRegister] | None = None,
         *,
@@ -109,13 +119,6 @@ def __init__(
         Args:
             circuit_cregs (list[ClassicalRegister]): Optional. List of ``cregs`` of the
                 circuit to which the instruction is added. Default: `None`.
-
-                .. deprecated:: 0.19
-                    The classical registers are insufficient to access all classical resources in a
-                    circuit, as there may be loose classical bits as well.  It can also cause
-                    integer indices to be resolved incorrectly if any registers overlap.  Instead,
-                    pass a complete requester to the ``resource_requester`` argument.
-
             resource_requester: A callable that takes in the classical resource used in the
                 condition, verifies that it is present in the attached circuit, resolves any indices
                 into concrete :obj:`.Clbit` instances, and returns the concrete resource.  If this
@@ -136,13 +139,6 @@ def __init__(
         if circuit_cregs is not None:
             if resource_requester is not None:
                 raise CircuitError("Cannot pass both 'circuit_cregs' and 'resource_requester'.")
-            warnings.warn(
-                "The 'circuit_cregs' argument to 'InstructionSet' is deprecated as of"
-                " qiskit-terra 0.19, and will be removed no sooner than 3 months after its release."
-                " Pass a complete resource requester as the 'resource_requester' instead.",
-                DeprecationWarning,
-                stacklevel=2,
-            )
             self._requester: Callable[..., ClassicalRegister | Clbit] = _requester_from_cregs(
                 tuple(circuit_cregs)
             )

qiskit/circuit/library/arithmetic/polynomial_pauli_rotations.py

@@ -14,12 +14,12 @@
 """Polynomially controlled Pauli-rotations."""
 
 from __future__ import annotations
-import warnings
 
 from itertools import product
 
 from qiskit.circuit import QuantumRegister, QuantumCircuit
 from qiskit.circuit.exceptions import CircuitError
+from qiskit.utils.deprecation import deprecate_func
 
 from .functional_pauli_rotations import FunctionalPauliRotations
 
@@ -225,15 +225,13 @@ def degree(self) -> int:
         return 0
 
     @property
+    @deprecate_func(
+        is_property=True,
+        since="0.16.0",
+        additional_msg="Instead, use the property :attr:`~num_ancillas`.",
+    )
     def num_ancilla_qubits(self):
         """Deprecated. Use num_ancillas instead."""
-        warnings.warn(
-            "The PolynomialPauliRotations.num_ancilla_qubits property is deprecated "
-            "as of 0.16.0. It will be removed no earlier than 3 months after the release "
-            "date. You should use the num_ancillas property instead.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
         return self.num_ancillas
 
     def _reset_registers(self, num_state_qubits):

qiskit/circuit/quantumregister.py

@@ -20,7 +20,7 @@
 from qiskit.circuit.exceptions import CircuitError
 
 # Over-specific import to avoid cyclic imports.
-from qiskit.utils.deprecation import deprecate_function
+from qiskit.utils.deprecation import deprecate_func
 from .register import Register
 from .bit import Bit
 
@@ -58,10 +58,12 @@ class QuantumRegister(Register):
     prefix = "q"
     bit_type = Qubit
 
-    @deprecate_function(
-        "Register.qasm() is deprecated since Terra 0.23, as correct exporting to OpenQASM 2 is "
-        "the responsibility of a larger exporter; it cannot safely be done on an object-by-object "
-        "basis without context. No replacement will be provided, because the premise is wrong.",
+    @deprecate_func(
+        additional_msg=(
+            "Correct exporting to OpenQASM 2 is the responsibility of a larger exporter; it cannot "
+            "safely be done on an object-by-object basis without context. No replacement will be "
+            "provided, because the premise is wrong."
+        ),
         since="0.23.0",
     )
     def qasm(self):

qiskit/test/base.py

@@ -227,7 +227,7 @@ def setUpClass(cls):
             r"elementwise comparison failed.*",
             r"The jsonschema validation included in qiskit-terra.*",
             r"The DerivativeBase.parameter_expression_grad method.*",
-            r"'Bit\.(register|index)' is deprecated.*",
+            r"The property ``qiskit\.circuit\.bit\.Bit\.(register|index)`` is deprecated.*",
             r"The CXDirection pass has been deprecated",
             r"The pauli_basis function with PauliTable.*",
             # Caused by internal scikit-learn scipy usage

test/python/circuit/test_instructions.py

@@ -568,14 +568,14 @@ def test_instructionset_c_if_deprecated_resolution(self):
         registers = [ClassicalRegister(2), ClassicalRegister(3), ClassicalRegister(1)]
         bits = [bit for register in registers for bit in register]
 
-        deprecated_regex = r"The 'circuit_cregs' argument to 'InstructionSet' is deprecated .*"
+        deprecated_regex = r".* argument ``circuit_cregs`` is deprecated .*"
 
         def dummy_requester(specifier):
             """A dummy requester that technically fulfills the spec."""
             raise CircuitError
 
         with self.subTest("cannot pass both registers and requester"):
-            with self.assertRaisesRegex(
+            with self.assertWarns(DeprecationWarning), self.assertRaisesRegex(
                 CircuitError, r"Cannot pass both 'circuit_cregs' and 'resource_requester'\."
             ):
                 InstructionSet(registers, resource_requester=dummy_requester)