Removed Deprecated Instruction.qasm Function (#11538)

* removed deprecated circuit.qasm function

* reno...

* reno.

* reno right location

* weird lint behavior

* lint fix...

* updated release note

* update release note

Co-authored-by: Jake Lishman <jake@binhbar.com>

* Update builder.py

---------

Co-authored-by: Jake Lishman <jake@binhbar.com>

qiskit/circuit/controlflow/builder.py

@@ -291,9 +291,6 @@ def _copy_mutable_properties(self, instruction: Instruction) -> Instruction:
     def assemble(self):
         raise CircuitError("Cannot assemble a placeholder instruction.")
 
-    def qasm(self):
-        raise CircuitError("Cannot convert a placeholder instruction to OpenQASM 2")
-
     def repeat(self, n):
         raise CircuitError("Cannot repeat a placeholder instruction.")
 

qiskit/circuit/instruction.py

@@ -45,8 +45,7 @@
 from qiskit.qobj.qasm_qobj import QasmQobjInstruction
 from qiskit.circuit.parameter import ParameterExpression
 from qiskit.circuit.operation import Operation
-from qiskit.utils.deprecation import deprecate_func
-from .tools import pi_check
+
 
 _CUTOFF_PRECISION = 1e-10
 
@@ -516,30 +515,6 @@ def _qasmif(self, string):
             )
         return "if(%s==%d) " % (self.condition[0].name, self.condition[1]) + string
 
-    @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="0.25.0",
-        package_name="qiskit-terra",
-    )
-    def qasm(self):
-        """Return a default OpenQASM string for the instruction.
-
-        Derived instructions may override this to print in a
-        different format (e.g. ``measure q[0] -> c[0];``).
-        """
-        name_param = self.name
-        if self.params:
-            name_param = "{}({})".format(
-                name_param,
-                ",".join([pi_check(i, output="qasm", eps=1e-12) for i in self.params]),
-            )
-
-        return self._qasmif(name_param)
-
     def broadcast_arguments(self, qargs, cargs):
         """
         Validation of the arguments.

qiskit/circuit/library/hamiltonian_gate.py

@@ -27,7 +27,6 @@
 from qiskit.circuit.exceptions import CircuitError
 from qiskit.quantum_info.operators.predicates import matrix_equal
 from qiskit.quantum_info.operators.predicates import is_hermitian_matrix
-from qiskit.utils.deprecation import deprecate_func
 
 from .generalized_gates.unitary import UnitaryGate
 
@@ -128,14 +127,6 @@ def _define(self):
         qc._append(UnitaryGate(self.to_matrix()), q[:], [])
         self.definition = qc
 
-    @deprecate_func(
-        since="0.25.0",
-        package_name="qiskit-terra",
-    )
-    def qasm(self):
-        """Raise an error, as QASM is not defined for the HamiltonianGate."""
-        raise CircuitError("HamiltonianGate has no OpenQASM 2 definition.")
-
     def validate_parameter(self, parameter):
         """Hamiltonian parameter has to be an ndarray, operator or float."""
         if isinstance(parameter, (float, int, np.ndarray)):

qiskit/circuit/library/standard_gates/x.py

@@ -15,7 +15,6 @@
 from typing import Optional, Union, Type
 from math import ceil, pi
 import numpy
-from qiskit.utils.deprecation import deprecate_func
 from qiskit.circuit.controlledgate import ControlledGate
 from qiskit.circuit.singleton import SingletonGate, SingletonControlledGate, stdlib_singleton_key
 from qiskit.circuit.quantumregister import QuantumRegister
@@ -590,24 +589,6 @@ def _define(self):
 
         self.definition = qc
 
-    @deprecate_func(since="0.25.0", package_name="qiskit-terra")
-    def qasm(self):
-        # Gross hack to override the Qiskit name with the name this gate has in Terra's version of
-        # 'qelib1.inc'.  In general, the larger exporter mechanism should know about this to do the
-        # mapping itself, but right now that's not possible without a complete rewrite of the OQ2
-        # exporter code (low priority), or we would need to modify 'qelib1.inc' which would be
-        # needlessly disruptive this late in OQ2's lifecycle.  The current OQ2 exporter _always_
-        # outputs the `include 'qelib1.inc' line.  ---Jake, 2022-11-21.
-        old_name = self.name
-        if not self.mutable:
-            copy_self = self.to_mutable()
-            copy_self.name = "c3sqrtx"
-            return copy_self.qasm()
-        try:
-            return super().qasm()
-        finally:
-            self.name = old_name
-
 
 @with_controlled_gate_array(_X_ARRAY, num_ctrl_qubits=3, cached_states=(7,))
 class C3XGate(SingletonControlledGate):

releasenotes/notes/deprecate-circuit-qasm-e5bbad027388e3f2.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    Removed the ``Instruction.qasm`` method, which was deprecated in Qiskit 0.45.0.
+    Use :func:`qiskit.qasm2.dump` with a complete :class:`.QuantumCircuit` instead.

test/python/circuit/test_circuit_qasm.py

@@ -266,11 +266,6 @@ def test_c3sxgate_roundtrips(self):
         parsed = QuantumCircuit.from_qasm_str(qasm)
         self.assertIsInstance(parsed.data[0].operation, C3SXGate)
 
-    def test_c3sxgate_qasm_deprecation_warning(self):
-        """Test deprecation warning for C3SXGate."""
-        with self.assertWarnsRegex(DeprecationWarning, r"Correct exporting to OpenQASM 2"):
-            C3SXGate().qasm()
-
     def test_cczgate_qasm(self):
         """Test that CCZ dumps definition as a non-qelib1 gate."""
         qc = QuantumCircuit(3)

test/python/circuit/test_hamiltonian_gate.py

@@ -24,7 +24,6 @@
 from qiskit.circuit import Parameter
 from qiskit.quantum_info import Operator
 from qiskit.converters import circuit_to_dag, dag_to_circuit
-from qiskit.circuit.exceptions import CircuitError
 
 
 class TestHamiltonianGate(QiskitTestCase):
@@ -89,14 +88,6 @@ def test_1q_hamiltonian(self):
         self.assertEqual(dnode.qargs, tuple(qc.qubits))
         assert_allclose(dnode.op.to_matrix(), np.eye(2))
 
-    def test_error_and_deprecation_warning_on_qasm(self):
-        """test that an error is thrown if the method `qasm` is called."""
-        matrix = np.zeros((2, 2))
-        hamiltonian_gate = HamiltonianGate(data=matrix, time=1)
-        with self.assertRaises(CircuitError):
-            with self.assertWarns(DeprecationWarning):
-                hamiltonian_gate.qasm()
-
     def test_2q_hamiltonian(self):
         """test 2 qubit hamiltonian"""
         qr = QuantumRegister(2)

test/python/circuit/test_instructions.py

@@ -655,15 +655,6 @@ def test_label_type_enforcement(self):
                 instruction = RZGate(0)
                 instruction.label = 0
 
-    def test_deprecation_warnings_qasm_methods(self):
-        """Test deprecation warnings for qasm methods."""
-        with self.subTest("built in gates"):
-            with self.assertWarnsRegex(DeprecationWarning, r"Correct exporting to OpenQASM 2"):
-                HGate().qasm()
-        with self.subTest("User constructed Instruction"):
-            with self.assertWarnsRegex(DeprecationWarning, r"Correct exporting to OpenQASM 2"):
-                Instruction("v", 1, 0, [0.4, 0.5, 0.5]).qasm()
-
 
 if __name__ == "__main__":
     unittest.main()

test/python/transpiler/test_mappers.py

@@ -74,6 +74,7 @@ def test_a_common_test(self):
 
 from qiskit import execute
 from qiskit import ClassicalRegister, QuantumRegister, QuantumCircuit, BasicAer
+from qiskit.qasm2 import dump
 from qiskit.transpiler import PassManager
 from qiskit.transpiler.passes import BasicSwap, LookaheadSwap, StochasticSwap, SabreSwap
 from qiskit.transpiler.passes import SetLayout
@@ -132,7 +133,7 @@ def generate_ground_truth(self, transpiled_result, filename):
         )
         self.assertDictAlmostEqual(self.counts, job.result().get_counts(), delta=self.delta)
 
-        transpiled_result.qasm(formatted=False, filename=filename)
+        dump(transpiled_result.qasm(formatted=False), filename)
 
     def assertResult(self, result, circuit):
         """Fetches the QASM in circuit.name file and compares it with result."""