Need a way to distinguish between nest-asyncio and nest-asyncio2 patch

[dagardner-nv]

Currently I find myself taking care to ensure that our thirds-party dependencies which will apply the nest-asyncio patch on import, are lazily imported, allowing my own library to apply the nest_asyncio2 patch instead.

I find myself writing code like this:

    # Make sure someone in our stack didn't already apply the older nest-asyncio patch
    assert not hasattr(asyncio, "_nest_patched")
    import nest_asyncio2
    nest_asyncio2.apply()

The main issue here is that I have no way to determine if nest_asyncio or nest_asyncio2 was applied.

Ideas:

1. In addition to the _nest_patched attribute, add a _nest2_patched attribute. If both are set then we know the nest_asyncio2 patch was applied, if only _nest_patched was set then nest_asyncio was applied.

2. Alternately since nest-asyncio only checks if the attribute exists, the value could be changed to 2 allowing for code like:

patched = getattr(asyncio, "_nest_patched", None)
if patched is None:
    # apply patch
elif patched == 2:
    # nest-asyncio2 is applied, we're good
elif patched is True:
    logger.warn("Attempted to apply nest_asyncio2, but nest_asyncio was already applied")

3. Add an optional argument to raise an exception on apply if nest-asyncio was applied first something like: def apply(loop=None, *, run_close_loop: bool = False, error_on_v1_patched: bool = False):

Edit by maintainer: related PR: NVIDIA/NeMo-Agent-Toolkit#1190

[Chaoses-Ib]

I think the ideal solution would be overriding patches made by nest_asyncio. But looks like there is no easy way to get the original values of overridden properties besides force reloading asyncio...

For adding attributes, I'd like to add a _nest_asyncio2. It'll hold the original properties for supporting unapplying and nest_asyncio2.run() in the future. And using the package name is less likely to conflict and easier to search.

3. Add an optional argument to raise an exception on apply if nest-asyncio was applied first something like: def apply(loop=None, *, run_close_loop: bool = False, error_on_v1_patched: bool = False):

Maybe we should also print a warning on Python ≥ 3.12 by default. Most people probably won't set error_on_v1_patched before they encounter problems.

[Chaoses-Ib]

https://github.com/Chaoses-Ib/nest-asyncio2/releases/tag/v1.7.1 released.

[dagardner-nv]

Woah! Thanks for the quick turn-around on this!