Reasoning why subprocess is not available over pexpect

[evanraalte]

Hi!

First of all thank you for providing this library!

.venv/lib/python3.12/site-packages/ansible_runner/config/runner.py line 74 sets self.runner_mode = "pexpect", without an apparent option to override it. What is the reason for doing it like this? In some of the other interface calls I do see the option to set subprocess instead.

The reason that I am asking this, is that in Python 3.12, I am getting Deprecation warnings on unit tests that use the ansible-runner:
DeprecationWarning: This process (pid=xxxx) is multi-threaded, use of forkpty() may lead to deadlocks in the child.

I isolated this to this minimal example, that shows that this is due to pexpect calls:

def test_pexpect_spawn_process():
    child = pexpect.spawn("python3")

I was able to "overwrite" the running_mode to use subprocess with this ugly hack:

        from ansible_runner import Runner
        from ansible_runner.utils import dump_artifacts

        def run_wrapper(**kwargs) -> Runner:  # type: ignore[no-untyped-def]  # noqa: ANN003
            dump_artifacts(kwargs)
            runner_config = ansible_runner.RunnerConfig(**kwargs)
            runner_config.prepare()
            runner_config.runner_mode = "subprocess"
            runner = Runner(runner_config)
            runner.run()
            return runner

And now my unit tests work as expected without the warning. However, I am not going to use this, as it seems like I am misusing the lib :). Can you perhaps clarify why it is that way? I searched through the latest docs, as well as for 2.4.0 (the version I am using), but could not find anything. Thank you in advance!