Support AsyncContentsManager?

[krassowski]

It would be great if jupytext supported usage with AsyncContentsManager. Currently such contents manager are explicitly ignored:

jupytext/jupyterlab/jupyterlab_jupytext/__init__.py

Lines 25 to 38 in 93cf493

	# If possible, we derive a Jupytext CM from the current CM
	base_class = app.contents_manager_class
	if asyncio.iscoroutinefunction(base_class.get):
	app.log.warning(
	f"[Jupytext Server Extension] Async contents managers like {base_class.__name__} "
	"are not supported at the moment "
	"(https://github.com/mwouts/jupytext/issues/1020). "
	"We will derive a contents manager from LargeFileManager instead."
	)
	from jupyter_server.services.contents.largefilemanager import ( # noqa
	LargeFileManager,
	)
	base_class = LargeFileManager

It looks like changes would need to be made to

jupytext/src/jupytext/contentsmanager.py

Line 51 in 93cf493

def build_jupytext_contents_manager_class(base_contents_manager_class):

to support deriving from AsyncContentsManager.

Are there specific reasons for not allowing it, or is it just that it needs to be implemented?

[mwouts]

Hey @krassowski , thank you for reaching out! Yes I would love to support this but so far I have not yet found nor the time nor the proper way to do this.

There is a very old PR that relates to this: #1021, but the change had a huge impact on tests etc so I could not get that in safely.

Maybe it would be better to duplicate the build_jupytext_contents_manager function to a new file that would implement the async support, and duplicate the tests as well to focus on the async support in new test files without impacting too much the existing (non-async) ones?