https://github.com/flying-sheep/pytest-doctest-import-twice

https://github.com/flying-sheep/pytest-doctest-import-twice

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• Host: GitHub
• URL: https://github.com/flying-sheep/pytest-doctest-import-twice
• Owner: flying-sheep
• Created: 2023-08-11T10:18:52.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-10-24T07:36:12.000Z (about 1 year ago)
• Last Synced: 2023-10-24T08:32:18.335Z (about 1 year ago)
• Language: Python
• Homepage: https://github.com/pytest-dev/pytest/issues/11306
• Size: 13.7 KB
• Stars: 0
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst

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README

        
pytest reproducer

=================

When using the following together, pytest 7.4.0 creates multiple instances of modules instead of reusing already-executed ones.

The bug triggers in pytest’s collection phase.

Necessary for the bug to trigger:

- ``--import-mode=importlib`` (I’m sure it’s also possible with ``append`` in another way)

- ``--doctest-modules``

- no ``src/`` layout

- importing from a submodule.

Run with e.g.

.. code:: bash

   hatch run pytest

   # or if you like typing

   python -m virtualenv .venv; source .venv/bin/activate; pip install -e .; pytest

No matter if you opt to install in dev mode like this, specify ``PYTHONPATH``,

or install regularly, the bug is reproducible in any case.

how it works

------------

The module in ``__init__.py`` gets created and executed twice,

but when each instance executes ``from .singleton import MyVindictiveSingleton``,

that reuses the same instance of the submodule.

.. code:: mermaid

   flowchart LR

   A[__init__.py] -->|imports| C(singleton.py)

   B[__init__.py] -->|imports| C(singleton.py)

tracebacks

----------

The two tracebacks are almost identical, but show that a cached version of a submodule is used

(fewer ``frozen importlib._bootstrap`` frames).

It’s also possible to put some code in ``conftest.py`` or a plugin and have the second execution there.

.. code:: pytb

   File "/lib/python3.11/site-packages/_pytest/pathlib.py", line 538, in import_path

     spec.loader.exec_module(mod)  # type: ignore[union-attr]

     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

   File "", line 940, in exec_module

   File "", line 241, in _call_with_frames_removed

   File "/pytest_doctest_import_twice/__init__.py", line 1, in 

     from .singleton import MyVindictiveSingleton

   File "", line 1178, in _find_and_load

   File "", line 1128, in _find_and_load_unlocked

   File "", line 241, in _call_with_frames_removed

   File "", line 1178, in _find_and_load

   File "", line 1149, in _find_and_load_unlocked

   File "", line 690, in _load_unlocked

   File "", line 940, in exec_module

   File "", line 241, in _call_with_frames_removed

   File "/pytest_doctest_import_twice/__init__.py", line 3, in 

     instance = MyVindictiveSingleton()

                ^^^^^^^^^^^^^^^^^^^^^^^

.. code:: pytb

   File "/lib/python3.11/site-packages/_pytest/pathlib.py", line 538, in import_path

     spec.loader.exec_module(mod)  # type: ignore[union-attr]

     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

   File "", line 940, in exec_module

   File "", line 241, in _call_with_frames_removed

   File "/pytest_doctest_import_twice/__init__.py", line 3, in 

     instance = MyVindictiveSingleton()

                ^^^^^^^^^^^^^^^^^^^^^^^