TypeError: arguments did not match any overloaded call QMutexLocker

[blluv]

Exception in callback _ProactorReadPipeTransport._loop_reading(<_OverlappedF...hed result=10>)
handle: <Handle _ProactorReadPipeTransport._loop_reading(<_OverlappedF...hed result=10>)>
Traceback (most recent call last):
  File "asyncio\events.py", line 80, in _run
  File "asyncio\proactor_events.py", line 301, in _loop_reading
  File "qasync\_windows.py", line 86, in recv_into
TypeError: arguments did not match any overloaded call:
  QMutexLocker(mutex: Optional[QMutex]): argument 1 has unexpected type 'QMutexLocker'
  QMutexLocker(mutex: Optional[QRecursiveMutex]): argument 1 has unexpected type 'QMutexLocker'
Traceback (most recent call last):
  File "qasync\_windows.py", line 196, in run
  File "qasync\_windows.py", line 69, in select
  File "qasync\_windows.py", line 149, in _poll
TypeError: arguments did not match any overloaded call:
  QMutexLocker(mutex: Optional[QMutex]): argument 1 has unexpected type 'QMutexLocker'
  QMutexLocker(mutex: Optional[QRecursiveMutex]): argument 1 has unexpected type 'QMutexLocker'

[HubKing]

Is this project dead?

[st-walker]

I think the maintainers typically reply to say it's not dead but nothing ever gets merged so 🤷

See:

#119 (comment)

[dnadlinger]

We are also seeing this on the latest release (in the context of https://github.com/m-labs/artiq on Windows):

  File "C:\Users\LabUser\AppData\Local\Programs\Python\Python311\Lib\asyncio\streams.py", line 332, in write
    self._transport.write(data)
  File "C:\Users\LabUser\AppData\Local\Programs\Python\Python311\Lib\asyncio\proactor_events.py", line 365, in write
    self._loop_writing(data=bytes(data))
  File "C:\Users\LabUser\AppData\Local\Programs\Python\Python311\Lib\asyncio\proactor_events.py", line 401, in _loop_writing
    self._write_fut = self._loop._proactor.send(self._sock, data)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\LabUser\AppData\Local\pypoetry\Cache\virtualenvs\artiq-oitg-UIB2HjkM-py3.11\Lib\site-packages\qasync\_windows.py", line 102, in send
    with QtCore.QMutexLocker(self._lock):
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: arguments did not match any overloaded call:
  QMutexLocker(mutex: Optional[QMutex]): argument 1 has unexpected type 'QMutexLocker'
  QMutexLocker(mutex: Optional[QRecursiveMutex]): argument 1 has unexpected type 'QMutexLocker'

I strongly suspect that this involves memory corruption or lifetime management issues, as self._lock is obviously not itself a QMutexLocker.

@blluv: Do you have a stand-alone reproducer for this?

[dnadlinger]

It would be interesting to see whether this also occurs with PySide instead of PyQt.

[halkony]

May not be totally related, but I was getting errors like this when using the QApplication from Pyside instead of qasync. Switching to the qasync one fixed the async crashes I was getting.

[halkony]

This was after determining that these crashes were memory faults by looking at the windows event viewer. For future readers, if you get unexplainable crashes from PyQT / Pyside, add this to your code to get the traceback.

import faulthandler
faulthandler.enable()

[dnadlinger]

May not be totally related, but I was getting errors like this when using the QApplication from Pyside instead of qasync. Switching to the qasync one fixed the async crashes I was getting.

Huh – isn't that just a re-exported version of the underlying PyQt/PySide one, though?

[halkony]

It seems you are correct. Nevertheless my application hasn't had a random crash from a thread since I made that change. Seems preposterous.

[dnadlinger]

And it wasn't maybe the auto-selelction causing you to switch to a different (Py)Qt library?