JSON-RPC python tests frequently fail with OSError: [Errno 9] Bad file descriptor

[link2xt]

Failure looks like this:

 ================================== FAILURES ===================================
_______________________________ test_acfactory ________________________________
[gw1] win32 -- Python 3.13.0 D:\a\deltachat-core-rust\deltachat-core-rust\deltachat-rpc-client\.tox\py\Scripts\python.EXE

acfactory = <deltachat_rpc_client.pytestplugin.ACFactory object at 0x000002049AC1DB50>

    def test_acfactory(acfactory) -> None:
        account = acfactory.new_configured_account()
        while True:
            event = account.wait_for_event()
            if event.kind == EventType.CONFIGURE_PROGRESS:
                assert event.progress != 0  # Progress 0 indicates error.
                if event.progress == 1000:  # Success
                    break
            else:
>               print(event)
E               OSError: [Errno 9] Bad file descriptor

tests\test_something.py:60: OSError

This looks like a problem with print usage in pytest when print attempts to print directly and something else (pytest?) closed the file descriptor.

pytest is configured in tox.ini with log_cli = true, maybe this changes something.

Here is CI log (from windows runner):
job-logs.txt

This is not the result of teardown, because by the time test_acfactory test failed with this print exception only 50% of tests passed and other tests continue to run successfully.

[link2xt]

This just happened another time with Windows:
https://github.com/deltachat/deltachat-core-rust/actions/runs/11440333909/attempts/1

Let's collect some failed runs to find out if it only happens on windows.

[link2xt]

Again Windows:
https://github.com/deltachat/deltachat-core-rust/actions/runs/11472543643/job/31925482766

[link2xt]

macOS failure:
https://github.com/deltachat/deltachat-core-rust/actions/runs/11489190507/job/31977700193

     def test_two_parallel_realtime_simultaneously(acfactory, path_to_webxdc):
        """Test two peers trying to establish connection simultaneously."""
        ac1, ac2 = acfactory.get_online_accounts(2)
        ac1.set_config("webxdc_realtime_enabled", "1")
        ac2.set_config("webxdc_realtime_enabled", "1")
    
        ac1_webxdc_msg, ac2_webxdc_msg = setup_realtime_webxdc(ac1, ac2, path_to_webxdc)
        ac1_webxdc_msg2, ac2_webxdc_msg2 = setup_realtime_webxdc(ac1, ac2, path_to_webxdc)
    
        setup_thread_send_realtime_data(ac1_webxdc_msg, [10])
        setup_thread_send_realtime_data(ac1_webxdc_msg2, [20])
        setup_thread_send_realtime_data(ac2_webxdc_msg, [30])
        setup_thread_send_realtime_data(ac2_webxdc_msg2, [40])
    
        wait_receive_realtime_data([(ac1_webxdc_msg, [30]), (ac1_webxdc_msg2, [40])])
>       wait_receive_realtime_data([(ac2_webxdc_msg, [10]), (ac2_webxdc_msg2, [20])])

tests/test_iroh_webxdc.py:147: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
tests/test_iroh_webxdc.py:73: in wait_receive_realtime_data
    log(f"msg {msg.id}: got correct realtime data {data}")
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

msg = 'msg 13: got correct realtime data [10]'

    def log(msg):
        print()
>       print("*" * 80 + "\n" + msg + "\n", file=sys.stderr)
E       OSError: [Errno 9] Bad file descriptor

tests/test_iroh_webxdc.py:28: OSError
----------------------------- Captured stdout call -----------------------------

[link2xt]

Another on Windows: https://github.com/deltachat/deltachat-core-rust/actions/runs/11491723293/job/31984758471?pr=6104