DAGCircuitError: 'bit mapping invalid: expected 1, got 2' for SXGate with reverse_ops after qpy roundtrip

[jiannanWang]

Environment

• Qiskit version: 0.46.1
• Python version: 3.11.8
• Operating system: Ubuntu 22.04.3 LTS

What is happening?

A circuit containing a SXGate with reverse_ops reports DAGCircuitError: 'bit mapping invalid: expected 1, got 2' after being qpy serialized and deserialized. Noticed that there's no error if not doing qpy serialization roundtrip.

How can we reproduce the issue?

from qiskit import QuantumCircuit,ClassicalRegister, QuantumRegister, transpile
from qiskit.circuit.library.standard_gates import SXGate

qr = QuantumRegister(2)
cr = ClassicalRegister(2)
qc = QuantumCircuit(qr, cr)
qc.append(SXGate().power(1).control(1).reverse_ops(), qr)

from qiskit import qpy
with open('circuit.qpy', 'wb') as fd:
    qpy.dump(qc, fd)
with open('circuit.qpy', 'rb') as fd:
    qc = qpy.load(fd)[0]

from qiskit_aer import Aer
backend = Aer.get_backend('qasm_simulator')
qc = transpile(qc, backend)

What should happen?

Traceback (most recent call last):
  File "/mnt/tests/reproduction/reproduce_bit_mapping_invalid.py", line 17, in <module>
    qc = transpile(qc, backend)
         ^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/compiler/transpiler.py", line 428, in transpile
    out_circuits = pm.run(circuits, callback=callback)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passmanager.py", line 561, in run
    return super().run(circuits, output_name, callback)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passmanager.py", line 580, in wrapper
    return meth(*meth_args, **meth_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passmanager.py", line 308, in run
    return super().run(
           ^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/passmanager/passmanager.py", line 224, in run
    out_program = _run_workflow(
                  ^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/passmanager/passmanager.py", line 286, in _run_workflow
    passmanager_ir, final_state = flow_controller.execute(
                                  ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/passmanager/base_tasks.py", line 218, in execute
    passmanager_ir, state = next_task.execute(
                            ^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/basepasses.py", line 195, in execute
    new_dag, state = super().execute(
                     ^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/passmanager/base_tasks.py", line 98, in execute
    ret = self.run(passmanager_ir)
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 247, in run
    decomposition, modified = self._recursively_handle_op(node.op, qubits)
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 336, in _recursively_handle_op
    dag = self.run(dag)
          ^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 247, in run
    decomposition, modified = self._recursively_handle_op(node.op, qubits)
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 336, in _recursively_handle_op
    dag = self.run(dag)
          ^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 247, in run
    decomposition, modified = self._recursively_handle_op(node.op, qubits)
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 336, in _recursively_handle_op
    dag = self.run(dag)
          ^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 247, in run
    decomposition, modified = self._recursively_handle_op(node.op, qubits)
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 336, in _recursively_handle_op
    dag = self.run(dag)
          ^^^^^^^^^^^^^
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 257, in run
    dag.substitute_node_with_dag(node, decomposition)
  File "/root/anaconda3/envs/qiskit46/lib/python3.11/site-packages/qiskit/dagcircuit/dagcircuit.py", line 1232, in substitute_node_with_dag
    raise DAGCircuitError(
qiskit.dagcircuit.exceptions.DAGCircuitError: 'bit mapping invalid: expected 1, got 2'

Any suggestions?

No response

[alexanderivrii]

This seems to have been fixed in Qiskit 1.0.