Bug 2339461

python-psycopg3 fails to build with Python 3.14.0a4.

There are many test failures treating warning as error:

________________________ test_identify_closure[asyncio] ________________________

pyfuncitem = <Function test_identify_closure[asyncio]>

    @pytest.hookimpl(tryfirst=True)
    def pytest_pyfunc_call(pyfuncitem: Any) -> bool | None:
        def run_with_hypothesis(**kwargs: Any) -> None:
            with get_runner(backend_name, backend_options) as runner:
                runner.run_test(original_func, kwargs)
    
        backend = pyfuncitem.funcargs.get("anyio_backend")
        if backend:
            backend_name, backend_options = extract_backend_and_options(backend)
    
            if hasattr(pyfuncitem.obj, "hypothesis"):
                # Wrap the inner test function unless it's already wrapped
                original_func = pyfuncitem.obj.hypothesis.inner_test
                if original_func.__qualname__ != run_with_hypothesis.__qualname__:
                    if iscoroutinefunction(original_func):
                        pyfuncitem.obj.hypothesis.inner_test = run_with_hypothesis
    
                return None
    
            if iscoroutinefunction(pyfuncitem.obj):
                funcargs = pyfuncitem.funcargs
                testargs = {arg: funcargs[arg] for arg in pyfuncitem._fixtureinfo.argnames}
>               with get_runner(backend_name, backend_options) as runner:

/usr/lib/python3.14/site-packages/anyio/pytest_plugin.py:116: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/usr/lib64/python3.14/contextlib.py:141: in __enter__
    return next(self.gen)
/usr/lib/python3.14/site-packages/anyio/pytest_plugin.py:43: in get_runner
    with asynclib.TestRunner(**backend_options) as runner:
/usr/lib/python3.14/site-packages/anyio/_backends/_asyncio.py:2022: in __init__
    asyncio.set_event_loop(self._loop)
/usr/lib64/python3.14/asyncio/events.py:843: in set_event_loop
    warnings._deprecated('asyncio.set_event_loop', remove=(3,16))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

name = 'asyncio.set_event_loop'
message = '{name!r} is deprecated and slated for removal in Python {remove}'

    def _deprecated(name, message=_DEPRECATED_MSG, *, remove, _version=sys.version_info):
        """Warn that *name* is deprecated or should be removed.
    
        RuntimeError is raised if *remove* specifies a major/minor tuple older than
        the current Python version or the same version but past the alpha.
    
        The *message* argument is formatted with *name* and *remove* as a Python
        version tuple (e.g. (3, 11)).
    
        """
        remove_formatted = f"{remove[0]}.{remove[1]}"
        if (_version[:2] > remove) or (_version[:2] == remove and _version[3] != "alpha"):
            msg = f"{name!r} was slated for removal after Python {remove_formatted} alpha"
            raise RuntimeError(msg)
        else:
            msg = message.format(name=name, remove=remove_formatted)
>           warn(msg, DeprecationWarning, stacklevel=3)
E           DeprecationWarning: 'asyncio.set_event_loop' is deprecated and slated for removal in Python 3.16

According to https://docs.python.org/dev/whatsnew/3.14.html#id3

asyncio policy system is deprecated and will be removed in Python 3.16. In particular, the following classes and functions are deprecated:
asyncio.AbstractEventLoopPolicy
asyncio.DefaultEventLoopPolicy
asyncio.WindowsSelectorEventLoopPolicy
asyncio.WindowsProactorEventLoopPolicy
asyncio.get_event_loop_policy()
asyncio.set_event_loop_policy()
asyncio.set_event_loop()
Users should use asyncio.run() or asyncio.Runner with loop_factory to use the desired event loop implementation.)


https://docs.python.org/3.14/whatsnew/3.14.html

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.14/fedora-rawhide-x86_64/08554972-python-psycopg3/

For all our attempts to build python-psycopg3 with Python 3.14, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14/package/python-psycopg3/

Testing and mass rebuild of packages is happening in copr.
You can follow these instructions to test locally in mock if your package builds with Python 3.14:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14/

Let us know here if you have any questions.

Python 3.14 is planned to be included in Fedora 43.
To make that update smoother, we're building Fedora packages with all pre-releases of Python 3.14.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires),
so if this package is required a lot, it's important for us to get it fixed soon.

We'd appreciate help from the people who know this package best,
but if you don't want to work on this now, let us know so we can try to work around it on our side.