pylint-dev/pylint

Use inference to determine if **kwargs is missing a named parameter

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#8,785 opened on Jun 18, 2023

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False Negative 馃Good first issueHacktoberfestNeeds PR

Description

I would expect these two lines to raise the same set of messages. We don't use inference to analyze whether **kwargs contains the missing named parameter x. We could.

import copy
import os

copy.copy(**{"y": os.environ})  # [unexpected-keyword-arg]
copy.copy(y=os.environ)  # [no-value-for-parameter, unexpected-keyword-arg]

False negative for no-value-for-parameter.

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python
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backendtoolingdeveloper experience
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bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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1-3 hours
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fresh
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clear
Prerequisites
Pythonpylint internalsinference engine
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate how pylint currently handles **kwargs in function calls. The issue points to a false negative for 'no value for parameter' when using **kwargs. Look at the codebase for inference logic related to keyword argument unpacking, likely in the checker for variable arguments. Consider how inference could be improved to detect missing named parameters when **kwargs is used. Relevant files may include pylint/checkers/typecheck.py or similar inference modules.
Use inference to determine if **kwargs is missing a named parameter 路 pylint-dev/pylint#8785 | Good First Issue