Unexpected error of QuantumCircuit.decompose with an instruction named qft

[t-imamichi]

Environment

• Qiskit version: 1.2.1 and main branch
• Python version: 3.12.6
• Operating system: macOS 14.7

What is happening?

If a quantum circuit includes an instruction named qft, decompose raises an error since 1.2.0.

How can we reproduce the issue?

from qiskit import QuantumCircuit

qc = QuantumCircuit(1)
qc2 = QuantumCircuit(1, name="qft")
qc.append(qc2.to_instruction(), qc.qregs[0])
print(qc.decompose())

# qiskit 1.1.2

q:

# qiskit 1.2.1 and main branch

Traceback (most recent call last):
  File "/Users/ima/tasks/4_2024/qiskit/terra/tmp/qft.py", line 6, in <module>
    print(qc.decompose())
          ^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/circuit/quantumcircuit.py", line 3240, in decompose
    dag = HighLevelSynthesis().run(dag)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 443, in run
    decomposition, modified = self._recursively_handle_op(node.op, qubits)
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 527, in _recursively_handle_op
    decomposition = self._synthesize_op_using_plugins(op, qubits)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 625, in _synthesize_op_using_plugins
    decomposition = plugin_method.run(
                    ^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/transpiler/passes/synthesis/high_level_synthesis.py", line 999, in run
    raise TranspilerError(
qiskit.transpiler.exceptions.TranspilerError: "The synthesis plugin 'qft.full` only applies to objects of type QFTGate."

What should happen?

No error

Any suggestions?

No response

[alexanderivrii]

Thanks for reporting this issue. I will submit a fix shortly. This is somewhat related to #13120.

[jakelishman]

Fixed by #13181