How to bypass mypyc when importing

[flying-sheep]

I want to import a module from its sources to avoid

TypeError: interpreted classes cannot inherit from compiled

How can I skip the .so files and do that?

[eli-schwartz]

Isn't this more of a question for the python interpreter? What should mypyc be doing at the point where cpython already attempted to load a .so, to make it load a .py instead?

[flying-sheep]

It is, I’m just asking if there’s a blessed way to do it.

I tried temporarily modifying sys.meta_path, but the following will fail with

AssertionError: Where do you come from?

and I’m completely stumped why.

def import_from_python(mod_name: str) -> ModuleType:
    assert mod_name not in sys.modules
    meta_path = sys.meta_path.copy()

    sys.meta_path[:] = [
        loader
        for loader in meta_path
        if getattr(loader, "__name__", None) != "ExtensionFileLoader"
    ]

    try:
        spec = find_spec(mod_name)
        assert spec
        assert type(spec.loader).__name__ != "ExtensionFileLoader", "Where do you come from?"
        return import_module(mod_name)
    finally:
        sys.meta_path[:] = meta_path

[eli-schwartz]

Again, that sounds like a question for the CPython repository?

[flying-sheep]

The actual issue is “interpreted classes cannot inherit from compiled”, which comes from mypyc.

I’m asking here to get an answer about the best way to deal with that. I assume that way is “import everything from the Python files somehow”, but I’m not sure.