Can't use asyncio event loop in widgets

[infmagic2047]

I am creating a widget that uses asyncio to run some external command (with asyncio.create_subprocess_exec). It doesn't work, and raises the RuntimeError("Cannot add child handler, the child watcher does not have a loop attached") exception instead.

If my understanding of the code is correct, calling set_event_loop after new_event_loop should fix this issue, but I'm not sure whether it will cause other problems.

[frostidaho]

Do you need stdout or stderr from the program? If not you could just use qtile.cmd_spawn().
You can also get at the underlying eventloop with qtile._eventloop, so you can call qtile._eventloop.subprocess_exec

[infmagic2047]

I need the stdout in this case, so I can't use cmd_spawn().

Using qtile._eventloop explicitly won't help here. subprocess_exec() uses asyncio.get_child_watcher() internally, which uses the event loop set with set_event_loop().

[mgeier]

I just stumbled upon this because I was getting the same error (but completely unrelated to qtile, I don't even know what that is).
I still have no clue about anything related with asyncio, but in my case something like this helped (called from the main thread):

asyncio.get_child_watcher().attach_loop(my_loop)

[github-actions]

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[ramnes]

Just got fixed by @tych0 , sorry it took so long!