Error `'coroutine' object is not subscriptable` when using `jupyter-fs==0.4.0` with `jupytext`

[mwouts]

With the recent release of jupyter-fs==0.4.0 two tests in jupytext started failing with the error 'coroutine' object is not subscriptable.

Apparently the issue is when Jupytext tries to load a configuration file using the contents manager:
https://github.com/mwouts/jupytext/actions/runs/6731638986/job/18296993244#step:8:453

Let me know if you see what could be the cause for this. Thanks

See also mwouts/jupytext#1150

[timkpaine]

I moved it to async contents managers, aeebe6f#diff-d599eec819a1aa6275f09579454402bbf5af9a9147256bad279aec31929774b5

xref mwouts/jupytext#1021

[mwouts]

I see, thanks for the confirmation.

What happens is that I am not sure when I will be able to make Jupytext compatible with async contents managers - the impact on the code and test collection is very significant, and I've not seen much demand for that yet. I will let mwouts/jupytext#1150 open until I can do something but that might take a while. Thanks

[timkpaine]

I can probably provide a sync contents manager, we don’t make any async calls yet

[mwouts]

Oh yes that would be very helpful indeed! That's probably the most easy way to restore the compatibility between our two projects. Happy to give it a try when you have a dev version ready. Thanks