bootstrap.py

# bootstrap.py
import sys
import importlib.util
import importlib.machinery

packages = []
sep = "_SEP_"

class CythonPackageExtensionFileLoader(importlib.machinery.ExtensionFileLoader):
    def create_module(self, spec):
        module = super().create_module(spec)
        package = spec.name.replace(sep, ".")
        if package not in packages:
            package = package[:len(package) - package[::-1].index(".") - 1]
        spec.name = spec.name.replace(sep, ".")
        module.__package__ = package
        module.__name__ = spec.name.replace(sep, ".")
        return module

class CythonPackageMetaPathFinder(importlib.abc.MetaPathFinder):
    def __init__(self, name_filter):
        super(CythonPackageMetaPathFinder, self).__init__()
        self.name_filter = name_filter

    def find_spec(self, fullname, path, target=None):
        if fullname.startswith(self.name_filter + ".") or fullname.startswith(self.name_filter + "_SEP_"):
            loader = CythonPackageExtensionFileLoader(fullname.replace(".", sep), __file__)
            spec = importlib.machinery.ModuleSpec(fullname.replace(".", sep), loader, origin=__file__, is_package=fullname in packages)
            return spec
        elif fullname == self.name_filter:
            return load_extensions(self.name_filter).__spec__

def load_extensions(basename):
    sys.meta_path.insert(0, CythonPackageMetaPathFinder(basename))
    loader = CythonPackageExtensionFileLoader(basename, __file__)
    spec = importlib.util.spec_from_loader(basename, loader, is_package=True)
    module = importlib.util.module_from_spec(spec)
    module.__package__ = basename
    loader.exec_module(module)
    sys.modules[basename] = module
    return module

sys.meta_path.insert(0, CythonPackageMetaPathFinder("pyunity"))