astroid 2.9.1 breaks pylint with missing __init__.py: F0010: error while code parsing: Unable to load file __init__.py

[interifter]

Steps to reproduce

Steps provided are for Windows 11, but initial problem found in Ubuntu 20.04

Update 2022-01-04: Corrected repro steps and added more environment details

1. Set up simple repo with following structure (all files can be empty):

root_dir/
|--src/
|----project/ # Notice the missing __init__.py
|------file.py # It can be empty, but I added `import os` at the top
|----__init__.py

2. Open a command prompt
3. cd root_dir
4. python -m venv venv
5. venv/Scripts/activate
6. pip install pylint astroid==2.9.1 # I also repro'd on the latest, 2.9.2
7. pylint src/project # Updated from pylint src
8. Observe failure:

src\project\__init__.py:1:0: F0010: error while code parsing: Unable to load file src\project\__init__.py:

Current behavior

Fails with src\project\__init__.py:1:0: F0010: error while code parsing: Unable to load file src\project\__init__.py:

Expected behavior

Does not fail with error.

If you replace step 6 with pip install pylint astroid==2.9.0, you get no failure with an empty output - since no files have content

python -c "from astroid import __pkginfo__; print(__pkginfo__.version)" output

2.9.1

python 3.9.1
pylint 2.12.2

This issue has been observed with astroid 2.9.1 and 2.9.2

[DanielNoord]

I can't seem to reproduce this in my virtualenv. This might be specific to venv? Needs some further investigation.

[DanielNoord]

@interifter Which version of pylint are you using?

[Pierre-Sassoulas]

Right, pip install pylint astroid==2.9.0, will keep the local version if you already have one, so I thought it was 2.12.2 but that could be false. In fact it probably isn't 2.12.2. For the record, you're not supposed to set the version of astroid yourself, pylint does, and bad thing will happen if you try to set the version of an incompatible astroid. We might want to update the issue's template to have this information next.

[interifter]

My apologies... I updated the repro steps with a critical missed detail: pylint src/project, instead of pylint src

But I verified that either with, or without, venv, the issue is reproduced.

Also, I never have specified the astroid version, before.

However, this isn't the first time the issue has been observed.
Back in early 2019, a similar issue was observed with either astroid 2.2.0 or isort 4.3.5, which led me to try pinning astroid==2.9.0, which worked.

[interifter]

@interifter Which version of pylint are you using?

2.12.2

Full env info:

Package           Version
----------------- -------
astroid           2.9.2
colorama          0.4.4
isort             5.10.1
lazy-object-proxy 1.7.1
mccabe            0.6.1
pip               20.2.3
platformdirs      2.4.1
pylint            2.12.2
setuptools        49.2.1
toml              0.10.2
typing-extensions 4.0.1
wrapt             1.13.3

[hippo91]

I confirm the bug and i'm able to reproduce it with python 3.9.1.

$> pip freeze
astroid==2.9.2
isort==5.10.1
lazy-object-proxy==1.7.1
mccabe==0.6.1
platformdirs==2.4.1
pylint==2.12.2
toml==0.10.2
typing-extensions==4.0.1
wrapt==1.13.3

[DanielNoord]

Bisected and this is the faulty commit:
2ee20cc

[DanielNoord]

Fix in #1333, no time to write tests yet so if somebody has any good ideas: please let me know!

[DanielNoord]

@interifter Fixed and released with 2.9.3. Thanks for the report and reproducible example. Not sure why I couldn't reproduce this to begin with.

[interifter]

@DanielNoord I had the incorrect steps to reproduce when I initially filed the bug, so that likely would prevent you, or anyone else, from being able to :)