importlib is probably not os.PathLike-clean due to its bootstrapping restrictions of not getting to use anything implemented in Python from 'os' (i.e. if it isn't being managed in posixmodule.c then it probably won't work).

If you follow the traceback it's trying to marshal a code object for the eventual .pyc file and failing (https://github.com/python/cpython/blob/faf49573963921033c608b4d2f398309d9f0d2b5/Lib/importlib/_bootstrap_external.py#L604). The real question is why is any unmarshallable object getting passed in the first place since that object is the code object that compile() returned.

Best guess? The compile() function is being given the path-like object (via https://github.com/python/cpython/blob/faf49573963921033c608b4d2f398309d9f0d2b5/Lib/importlib/_bootstrap_external.py#L848) and it's blindly setting it on the code object itself, and then marhsal fails since it can't handle pathlib.Path. If my hunch is right, then the possible solutions are:

- Don't do that 😉
- Make compile() aware of path-like objects
- Have importlib explicitly work around compile()'s shortcoming by doing the right thing for path-like objects before passing in the the 'path' argument.