BleakScannerWinRT import fails in Jupyter Notebook - [WinError -2147417850] Cannot change thread mode after it is set

[datoslabs]

• bleak version: 0.13.0
• Python version: 3.8.8
• Operating System: Windows 10
• BlueZ version (bluetoothctl -v) in case of Linux: N/A

Description

Hi,

New to bleak. I encountered [WinError -2147417850] Cannot change thread mode after it is set when I attempted to import the scanner with the following:

from bleak.backends.winrt.scanner import (
        BleakScannerWinRT as BleakScanner,
    ) 

After some googling, it appears to be a known issue trying to initialize winrt with MTA in Jupyter Notebook. I was able to avoid the error by:

1. Install winrt
2. Execute the following twice (the first execution resulted in the same error but the second time will run without errors) :

import importlib
_winrt=importlib.import_module("winrt._winrt")
_winrt.uninit_apartment()
import winrt

3. Afterwards, running the following to import BleakScannerWinRT works without any error:

from bleak.backends.winrt.scanner import (
        BleakScannerWinRT as BleakScanner,
    ) 

Is this the right approach? I seemed to be able to scan and discover my BLE device; I am still getting familiar with this library to read the characteristics so I am not sure if I would run into any problems down the road.

[dlech]

Hmm... now that we have our own bleak-winrt package, we should probably set the default to be STA instead of MTA to avoid the need for such workarounds.

[hbldh]

I ran into this trying to debug from VS Code. It is a shame if such a basic and not at all uncommon operation produces an error. I am way too uninitiated in why it is needed to say what the default should be, but in general I think Bleak should aim for making things as non-problematic for the non-experts as possible.