Strip _v2 from name in fake BackendV2 classes

[pedrorrivero]

Environment

• Qiskit Terra version: 0.22.2
• Python version: 3.11
• Operating system: MacOS

What is happening?

Fake BackendV2 classes have _v2 appended to the end of their names despite the fact that they use the same device specification as their BackendV1 counterparts.

This is inconsistent with the naming convention used for real backends, where the name is independent of the backend version that exposes it; making such name exclusively tight to the underlying device and therefore a good device identifier.

How can we reproduce the issue?

from qiskit.providers.fake_provider import FakeNairobi, FakeNairobiV2
from qiskit.providers import BackendV2Converter

backend = BackendV2Converter(FakeNairobi())
print(f"{backend.name=!r}")

backend = FakeNairobiV2()
print(f"{backend.name=!r}")

Outputs:

backend.name='fake_nairobi'
backend.name='fake_nairobi_v2'

What should happen?

Name attr in fake backends should depend only on the fake device that gets exposed, and not on the Backend version that exposes it (i.e. consistent with the behavior for real backends).

Any suggestions?

Strip _v2 from name in fake BackendV2 classes.

[shivalee12]

I would like to work on this issue

[kdk]

This seems reasonable to me. @mtreinish Can you say if the _v2 on the backend names was needed, or if it's okay to be removed?

[HuangJunye]

@kdk The _v2 was introduced by me in this PR #7643 and I didn't give much thoughts about it at the time. We had a Slack discussion about this and the consensus is to remove it. We should use isinstance(backend, BackendV2) instead of backend name to check backend version.

[kdk]

Thanks for the context @HuangJunye , that sounds good to me!

[shivalee12]

hi sorry for the late response, I had exams going on
Could you please also elaborate on which sections of notes should be updated?
deprecation and fixes? or issues as well?

[HuangJunye]

hi sorry for the late response, I had exams going on Could you please also elaborate on which sections of notes should be updated? deprecation and fixes? or issues as well?

@shivalee12 the upgrade section is suitable for this change.