Hi,
I feel there is a bug in SonarLint’s Python rule python:S1940 in that it gives semantic changing advice in some case when the variables are sets.
As an example, consider:
from typting import Set
def validate(a: Set[str], b: Set[str]) -> None:
if not (a <= b):
raise ValueError("a <= b")
In this case, SonarLint will suggest via python:s1940 that I should simplify my logic to if a > b:. However, applying this rewrite would change the semantics as what we are testing here is whether a is a subset of b (i.e., all the values in a are inside the set b). The rewritten on the other hand tests something “entirely different” (namely that b is not a superset of a). This is problematic when b is used as an “approval list”.
I think python:S1940 should account for this case when the variables are “clearly” defined as sets and not suggest this particular rewrite (the not (a == b) variant is still fine for sets AFAICT).
A minimal reproducer where this rewrite goes wrong:
>>> from typing import Set
>>> ingredients: Set[str] = {'beef', 'potatos'}
>>> consumable_by_vegans: Set[str] = {'nut', 'apple', 'potatos'}
>>> if not (ingredients <= consumable_by_vegans):
... raise ValueError("Sorry, the selected ingredients are not vegan")
...
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
ValueError: Sorry, the selected ingredients are not vegan
>>> if ingredients > consumable_by_vegans:
... raise ValueError("Sorry, the selected ingredients are not vegan")
...
>>> # Oops, no exception! :-/
Thanks for considering.
Product info:
- Operating system: Linux
- SonarLint plugin version: 7.3.0.59206
- Programming language you’re coding in: Python
- Is connected mode used: No