I’m working on a project where I need to override files located in the ./lib/python3.9/site-packages” directory. I have the following hook that does just that using importlib.util and sys.meta_path.insert:

• The Override files is in ./lib_changes/*.

• The Hook does work in all of the following files except the zope+intid.__init__.py file

import re
import sys
import importlib.util
import os
from Zope2.Startup.serve import main
import logging

LOGGER = logging.getLogger("RunWSGI")

def generate_override_mapping(lib_changes_dir):
    override_mapping = {}
    for filename in os.listdir(lib_changes_dir):
        if filename.endswith(".py"):
            module_name = filename[:-3].replace("+", ".")
            # Special handling for __init__.py files
            if module_name.endswith(".__init__"):
                module_name = module_name[:-9]
            override_mapping[module_name] = os.path.join(lib_changes_dir, filename)
    return override_mapping

class CustomImportHook:
    def __init__(self, override_mapping):
        self.override_mapping = override_mapping
        self.override_counter = 0

    def find_spec(self, fullname, path=None, target=None):
        
        if fullname in self.override_mapping:
            override_path = self.override_mapping[fullname]
            LOGGER.info(f"{fullname} Overide by {override_path}")
            self.override_counter += 1

            return importlib.util.spec_from_file_location(fullname, override_path)

        return None


lib_changes_dir = '/opt/projects/Plone/site/backend/lib_changes'
override_mapping = generate_override_mapping(lib_changes_dir)

sys.meta_path.insert(0, CustomImportHook(override_mapping))

if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script.pyw|.exe)?$', '', sys.argv[0])
    sys.exit(main())

Problem: I’m trying to override zope.intid.__init__.py (or any .__init__.py file) with a custom implementation located in a different directory. However, I’m encountering an issue where the package submodules are not recognized correctly, leading to ModuleNotFoundError errors. For example, once the Hook successfully replaced the implementation of zope.intid.__init__.py with the one located at ./lib_changes, improts such as import zope.intid.interfaces is not longer working (err: ModuleNotFoundError: No module named 'zope.intid.interfaces'; 'zope.intid' is not a package.

Question: How can I properly override the __init__.py of the zope.intid package (or any .__init__.py package file) without breaking the import of its submodules? Is there a way to correctly set up the custom import hook to handle this scenario?