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ruff/crates
Sebastian Pipping 85ca5b7eed Fix last example of flake8-bugbear rule B023 "function uses loop variable" (#10913)
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## Summary

Hi! 👋 

Thanks for sharing ruff as software libre — it helps me keep Python code
quality up with pre-commit, both locally and CI 🙏

While studying the examples at
https://docs.astral.sh/ruff/rules/function-uses-loop-variable/#example I
noticed that the last of the examples had a bug: prior to this fix, `ì`
was passed to the lambda for `x` rather than for `i` — the two are
mixed-up. The reason it's easy to overlook is because addition is an
commutative operation and so `x + i` and `i + x` give the same result
(and least with integers), despite the mix-up. For proof, let me demo
the relevant part with before and after:

```python
In [1]: from functools import partial

In [2]: [partial(lambda x, i: (x, i), i)(123) for i in range(3)]
Out[2]: [(0, 123), (1, 123), (2, 123)]

In [3]: [partial(lambda x, i: (x, i), i=i)(123) for i in range(3)]
Out[3]: [(123, 0), (123, 1), (123, 2)]
```

Does that make sense?

## Test Plan

<!-- How was it tested? -->
Was manually tested using IPython.


CC @r4f @grandchild
2024-04-12 20:07:52 +00:00
..
2024-04-12 03:39:45 +00:00