为什么 pylint 为 numpy.ndarray.shape 返回“unsubscriptable-object”？

Question

I just put together the following "minimum" repro case (minimum in quotes because I wanted to ensure pylint threw no other errors, warnings, hints, or suggestions - meaning there's a bit of boilerplate):

pylint_error.py :

"""
Docstring
"""

import numpy as np


def main():
    """
    Main entrypoint
    """
    test = np.array([1])
    print(test.shape[0])


if __name__ == "__main__":
    main()

When I run pylint on this code ( pylint pylint_error.py ) I get the following output:

$> pylint pylint_error.py
************* Module pylint_error
pylint_error.py:13:10: E1136: Value 'test.shape' is unsubscriptable (unsubscriptable-object)

------------------------------------------------------------------
Your code has been rated at 1.67/10 (previous run: 1.67/10, +0.00)

It claims that test.shape is not subscriptable, even though it quite clearly is. When I run the code it works just fine:

$> python pylint_error.py
1

So what's causing pylint to become confused, and how can I fix it?

Some additional notes:

• If I declare test as np.arange(1) the error goes away
• If I declare test as np.zeros(1) , np.zeros((1)) , np.ones(1) , or np.ones((1)) the error does not go away
• If I declare test as np.full((1), 1) the error goes away
• Specifying the type ( test: np.ndarray = np.array([1]) ) does not fix the error
• Specifying a dtype ( np.array([1], dtype=np.uint8) ) does not fix the error
• Taking a slice of test ( test[:].shape ) makes the error go away

My first instinct says that the inconsistent behavior with various NumPY methods ( arange vs zeros vs full , etc) suggests it's just a bug in NumPY . However it's possible there's some underlying concept to NumPY that I'm misunderstanding. I'd like to be sure I'm not writing code with undefined behavior that's only working on accident.

Answer 1

I don't have enough reputation to comment, but it looks like this is an open issue: https://github.com/PyCQA/pylint/issues/3139

Until the issue is resolved on their end, I would just change the line to

    print(test.shape[0])  # pylint: disable=E1136  # pylint/issues/3139

to my pylintrc file.

Answer 2

As of November 2019:

As mentioned by one of the users in the discussion on GitHub you could resolve the problem by downgrading both pylint and astroid , eg in requirements.txt

astroid>=2.0, <2.3
pylint>=2.3, <2.4

or

pip install astroid==2.2.5 & pip install pylint==2.3.1

Answer 3

This was finally fixed with the release of astroid 2.4.0 in May 2020.

https://github.com/PyCQA/pylint/issues/3139