caronc / 117860-cpython-issue

Proof-of-Error: unittest.mock.patch broken for Python >= 3.11

Python v3.10 and >3.11 Handle Imports Incorrectly

This repository was created to show that the __all__ references within a module being mocked are not honored in versions of Python v3.11 and higher.

This repository was created to cross reference Issue: cpython/117860. The failed Git Action tasks associate wit this repository demonstrate the inconsistency in the handling of unittest.mock.patch() importing.

All versions of Python (v2.x+, and 3.x) up until v3.10 successfully allow mocking of Apprise notify function as:

• unittest.mock.patch('apprise.Apprise.notify')

However this breaks in the introduction of Python v3.11 (and v3.12 also) requiring that the patch declaration change to:

• unittest.mock.patch('apprise.Apprise.Apprise.notify')

The problem is the new required path is not backwards compatible with previous versions of Python, and the old required path is not compatible with the new.

The original path is the correct one; something changed in Python v3.11 that caused the import rules to be ignored. This however is NOT the case for just a regular import of the module (outside of unittest). Python v3.11 still allows a from apprise import Apprise which is correct (and further pointing out the new inconsitency).

Demonstration

First acquire this repository into your own environment:

# Clone repo
git clone [e-mail]:caronc/117860-cpython-issue.git

# Change into our directory
cd 117860-cpython-issue

Now in this directory there are 3 Dockerfiles you can use.

1. Python v3.10; this one works perfect (based on python:3.10-buster):

   docker-compose run --service-ports --rm test.py310 pytest

   It will fail to run the tests I had to modify to make worth with Python v3.11+ as the do not honor the __all__ and Python v3.10 does. It throws:

   # test/test_py11_higher_only.py
   ModuleNotFoundError: No module named 'apprise.Apprise.Apprise'; 'apprise.Apprise' is not a package
   

2. Python v3.11; this one however fails (based on python:3.11-buster):

   docker-compose run --service-ports --rm test.py311 pytest

   It will throw:

   # test/test_py10_lower_only.py
   AttributeError: <module 'apprise.Apprise' from '/usr/local/lib/python3.11/site-packages/apprise/Apprise.py'> does not have the attribute 'notify'
   

   This demonstrates that the __all__ is not being properly referenced. What is interesting is that importing the module directly works fine in this version (proving that the __all__ is however being honorted in some cases ). You can witness this by doing the following:

   docker-compose run --service-ports --rm test.py311 python

   Then type:

   # Thanks to __all__ functionality; this is actually apprise.Apprise.Apprise
   # but made easy
   from apprise import Apprise
   
   # You will safetly land here and can now do something like:
   ap_obj = Apprise()

You can see the __all__ reference in the Apprise source here which is located in the apprise.__init__.py file to make the class imports easier for external users.

Expected Results

• The test/test_py11_higher_only.py is a bad test all around and should fail with all Python versions
• The test/test_py10_lower_only.py should work with all Python versions