python / python/cpython

unittest.mock.patch('path') neither forwards or backwards compatible starting from Python >= v3.11

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topic-importlib type-bug
Lenguaje dominante
Python
Estrellas
77.2k
Forks
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Descripción

Bug report

Bug description:

Issue

It appears that Python v3.11 and v3.12 are not respecting project functions and classes relative to the module root (module.__init__) when running tests and leveraging unittest.mock.

Proof of Failure

👉 I created a project that can be found here which demonstrates the entire situation.

You can review the import failures across the multiple versions of Python here

Expected Behavior

That the following would work in Python >= 3.11 as it does with all previous versions:

import sys
from unittest import mock


# This actually retrieves apprise.Apprise.Apprise().notify when using
# earlier versions of py.test (hence apprise.__init__.__all__ is respected)
@mock.patch("apprise.Apprise.notify")
def test_py11_and_higher_fails(mock_notify):
    """
    Only works with Python v3.10

    Python v3.11+ produces (where ?? is swapped with 11, or 12 respectively to whichever version of Python is being tested):
    AttributeError: <module 'apprise.Apprise' from '/usr/local/lib/python3.??/site-packages/apprise/Apprise.py'> does not have the attribute 'notify
    """
    pass

For it to work in newer versions of Python, the modules internal object placements are ignored. The following does however work (but incompatible with Python v3.10 and less):

# ...
@mock.patch("apprise.Apprise.Apprise.notify")
def test_py10_and_lower_fails(mock_notify):
     ...

Apprise Background

I'm not sure if this information is relavant; but perhaps the issue is centered around the module itself I'm testing against that makes use of the __all__ setting. Just incase; here are details that surround it:

The __init__ residing in the Apprise Module identifies:

# Get our class Apprise() from within the Apprise.py file
from .Apprise import Apprise

__all__ = [
 'Apprise',  #...
]

Regular Usage Works

Despite testing failing, all versions of the Python continue to respect import and correctly source the class/function refernced within the modules (inconsisent with unittest). The following works great:

# pip install apprise

# All versions of Python correctly respect module definitions here.
from apprise import Apprise

# Do our magic with it. 
obj = Apprise()

After Thoughts

At first I thought there was an issue with py.test but since Pytest v8.1.1 works in Python v3.10 but not in Python v3.11 or v3.12, I decided to open the ticket here. But the issue seems to be related to unittest.mock.patch and centers around Python v3.11 and higher.

Personally, I feel I've exhausted all avenues with my own research, so hopefully you can help me share what could have been introduced. Any tips/help would be much appreciated. 🙏

CPython versions tested on:

3.6, 3.7, 3.8, 3.9, 3.10, 3.11, 3.12

  • bolded are impacted by issue.
Operating systems tested on:

Linux

Linked PRs
  • gh-118176
  • gh-118432

Guía de contribución

Abrir la guía de contribución

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

Línea de trabajo

Reproduce el comportamiento usando unittest.mock.patch con el ejemplo de Apprise y compara los resultados de Python 3.10, 3.11 y 3.12 mostrados en el proyecto enlazado y en la ejecución de GitHub Actions. Lee apprise/init.py y el punto de entrada de resolución del destino del patch; después, revisa los PR enlazados gh-118176 y gh-118432. Se considera terminado cuando el comportamiento previsto del destino del patch queda establecido en todas las versiones de Python indicadas y cuenta con cobertura de regresión.

Escrito por el modelo de indexación a partir del texto del issue.

Evaluación

Stack tecnológico
python
Área
testing-qa
Tipo de issue
Error
Dificultad
4/5
Tiempo estimado
3-5 días
Estado de actividad
Estancado
Claridad
Bastante claro
Aptitud para principiantes
30/100

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