Event Loop Policies Will Be Deprecated in Python 3.14

[johnzhou721]

See https://docs.python.org/3.15/library/asyncio-policy.html

[johnzhou721]

All that is needed to solve this problem is to rework this block at the end of dunder init:

class QEventLoopPolicyMixin:
    def new_event_loop(self):
        return QEventLoop(QApplication.instance() or QApplication(sys.argv))


class DefaultQEventLoopPolicy(
    QEventLoopPolicyMixin,
    asyncio.DefaultEventLoopPolicy,
):
    pass


@contextlib.contextmanager
def _set_event_loop_policy(policy):
    old_policy = asyncio.get_event_loop_policy()
    asyncio.set_event_loop_policy(policy)
    try:
        yield
    finally:
        asyncio.set_event_loop_policy(old_policy)


def run(*args, **kwargs):
    with _set_event_loop_policy(DefaultQEventLoopPolicy()):
        return asyncio.run(*args, **kwargs)

and make run use set_event_loop instead of the policy stuff.

We can still expose an API for event loop policy by making the 2 classes go under a smaller than Python 3.16 check and make them raise some strong warnings.

[hosaka]

Will be deprecated in 3.14 prior to removal in 3.16. As mentioned in #131, this issue should be addressed when:

• 3.14 is released (instead of adding 3.14-dev target)
• pyside/pyqt support 3.14

[hosaka]

Fixed in #140