OpenCV vs Pylint - E0611:no-name-in-module -

[Senja20]

Bug description

I have an issue with PyLint and OpenCV. Whenever I import something from openCV I get the following error Pylint (E0611:no-name-in-module). Why doesn't it see the models in the cv2 library, as it does with other libraries?

Configuration

No response

Command used

pylint $(git ls-files '*.py')

Pylint output

************* Module utils.process_video
YOLO-detect-buoys\utils\process_video.py:7:0: E0611: No name 'VideoCapture' in module 'cv2' (no-name-in-module)
YOLO-detect-buoys\utils\process_video.py:7:0: E0611: No name 'destroyAllWindows' in module 'cv2' (no-name-in-module)
YOLO-detect-buoys\utils\process_video.py:7:0: E0611: No name 'imshow' in module 'cv2' (no-name-in-module)
YOLO-detect-buoys\utils\process_video.py:7:0: E0611: No name 'polylines' in module 'cv2' (no-name-in-module)
YOLO-detect-buoys\utils\process_video.py:7:0: E0611: No name 'waitKey' in module 'cv2' (no-name-in-module)

------------------------------------------------------------------
Your code has been rated at 6.84/10 (previous run: 6.84/10, +0.00)

Behavior

This is the resulting behavior:

Pylint version

pylint 3.1.0
astroid 3.1.0
Python 3.11.4 (tags/v3.11.4:d2340ef, Jun  7 2023, 05:45:37) [MSC v.1934 64 bit (AMD64)]

OS / Environment

Windows 11 23H2, Powershell

Additional dependencies

opencv-python==4.9.0.80
packaging==24.0
pafy==0.5.5
pandas==2.2.1
pillow==10.2.0
pluggy==1.4.0
psutil==5.9.8
py-cpuinfo==9.0.0
pycryptodomex==3.20.0
pyparsing==3.1.2
python-dateutil==2.9.0.post0
python-dotenv==1.0.1
python-magic==0.4.27

[UlrichEckhardt]

I can reproduce that on Ubuntu 22.04 with Python 3.10.12. As a test file, I'm using

import cv2
cv2.VideoCapture

The steps for setup are:

mkdir issue9566
cd issue9566/
python3 -m venv pyenv
source pyenv/bin/activate.fish
pip install --upgrade pip setuptools
pip install pylint==3.1.0
pip install opencv-python==4.9.0.80
python demo.py # no output, in particular no errors!
pylint --verbose demo.py 

This produces the following output

No config file found, using default configuration
************* Module demo
demo.py:1:0: C0114: Missing module docstring (missing-module-docstring)
demo.py:2:0: W0104: Statement seems to have no effect (pointless-statement)
demo.py:2:0: E1101: Module 'cv2' has no 'VideoCapture' member (no-member)

---------------------------------------------------------------------------------------------------
Your code has been rated at 0.00/10 (previous run: 8.80/10, -8.80)
Checked 1 files, skipped 1 files

I looked into cv2 a bit and found this:

Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> print(cv2.__all__)
[]
>>> 'VideoCapture' in dir(cv2)
True
>>> cv2.VideoCapture
<class 'cv2.VideoCapture'>

Looking at https://stackoverflow.com/a/64130/1968182, an empty or partial __all__ is not per-se a bug, though I'm no expert on the topic of Python modules. I guess this isn't just about OpenCV, but about exported names that are not part of __all__.

[Pierre-Sassoulas]

Thank you for triaging @UlrichEckhardt, this is probably an issue with pylint not understanding python code that is "too dynamic" or C code inside OpenCV. Could require an astroid brain or an evolution in astroid to understand a particular dynamic code construct.

[UlrichEckhardt]

I just tried to reproduce this in three ways:

1. A single module file
2. A single init.py file in a directory
3. An init.py file which imports a name from another module file in that dir

In all three cases, __all__ was explicitly set to an empty list. In all three cases, I couldn't find any misbehaviour on pylint's part, so it may be specific to binary modules indeed.