Python 3.11 incompatibility: some calls to random.sample() pass a set

[mhucka]

Using a set in a call to the sample(…) method from the Python random standard library has been deprecated since Python 3.9, and in Python 3.11, it causes an error. This happens in the function util.py:_apply_random_control(…) starting on line 111:

open_qubits = set(all_qubits) - set(gate.qubits)
n_open = min(len(open_qubits), 3)
if n_open == 0:
    # No open qubits to control. Return unmodified gate.
    return gate
control_locs = random.sample(open_qubits, n_open)

There may be other places where it happens, so we should do a sweep through
the code to look for calls to sample().

[Aniketsy]

Hi @mhucka,

I would like to work on fixing this issue. Since random.sample() no longer accepts sets in Python 3.11, I can update the codebase to wrap sets in list() (or sorted() where deterministic behavior is required) before sampling.

Please correct me if I’m wrong about this approach.

Thanks, and I’d be happy to submit a PR once I get your guidance.

[mhucka]

@Aniketsy Thank you for your interest. I'll go ahead and assign it to you, but note that currently it is difficult to build TFQ. It's something I'm working on improving, but working with TFQ may be challenging until that's done.

[Aniketsy]

Thank you for assigning me this issue. I understand that building TFQ is currently challenging. I’ll give it a try and do my best to work through the setup.
I’ll reach out for guidance if I run into any difficulties.