deprecation warning with Python 3.10

[jnoortheen]

Python 3.10 is still beta. This is just a heads up. Here is the full warning

xsh-rVZlQJi1-py3.10/lib/python3.10/site-packages/prompt_toolkit/application/application.py:878: DeprecationWarning: There is no current event loop
  loop = get_event_loop()

[jonathanslenders]

Thanks for bringing this to my attention!

Given that we are still supporting Python 3.6, I think we need a wrapper (in prompt_toolkit/eventloop/utils.py) that uses get_running_loop if available and otherwise get_event_loop. Is this something you're interested in contributing?

There are various places where it's used:

./shortcuts/prompt.py
./shortcuts/dialogs.py
./shortcuts/progress_bar/base.py
./shortcuts/utils.py
./input/vt100.py
./input/win32.py
./history.py
./application/application.py
./contrib/telnet/server.py
./contrib/ssh/server.py
./eventloop/inputhook.py
./eventloop/async_generator.py
./eventloop/utils.py

[jnoortheen]

@jonathanslenders yes I am. This means updating the github actions as well right?

[jaraco]

Python 3.10 is no longer beta and this issue still exists, affecting all xonsh environments that use ptk.

[mattmc3]

Any updates on this issue? A fresh install of Xonsh will emit this deprecation error on every command since Python 3.10 is now out.

Instead of adding something to prompt_toolkit/eventloop/utils.py, would it preferable to do a simple conditional import in the relevant files? I'm willing to attempt a PR:

try:
    from asyncio import get_running_loop
except ImportError:
    from asyncio import get_event_loop as get_running_loop

Or, you can add get_running_loop to asyncio for Python 3.6:

import asyncio
if not hasattr(asyncio, 'get_running_loop'):
    asyncio.get_running_loop = asyncio.get_event_loop

[mattmc3]

I opened a PR. See above.

[henryiii]

FYI, brew has now switched the xonsh recipe to Python 3.10, so this pops up all the time on any brew installed xonsh. Brew has migrated over 150 formula, and is migrating the other 450, so this will pop up on anything that moves to Python 3.10 and uses prompt-toolkit.

[mattmc3]

Vote to close this issue. Can confirm that prompt-toolkit 3.0.22 works great in Xonsh on Python 3.10 with my merged PR. For Xonsh users, you can simply xpip install prompt-toolkit --upgrade if you are on an earlier version and still seeing the deprecation warning.