PyCQA/flake8-bugbear

Proposed rule: match zip() arguments and unpacked variables

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#545 opened on Feb 25, 2026

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Description

In an older code blob of mine I came across this oddity:

for a, b, _ in zip(iter_a, iter_b, iter_c):
    ...

which should be simplified to

for a, b in zip(iter_a, iter_b):
    ...

by removing iter_c entirely. Turns out I had this pattern in two other places as well 🤦🏻‍♂️

Would this not be a useful idiom to look for and warn about? (Assuming _ isn’t used in the body of the loop…)

Contributor guide

Research direction
Implement a new flake8 rule that detects when a variable ` ` is used in unpacking from `zip()` with more iterables than needed, and suggests removing the extra iterable. Check that ` ` is not used elsewhere in the loop body.
Tech stack
python
Domain
toolingdeveloper experience
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Python
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60