chore: fix pylint message use-set-for-membership

[jenstroeger]

This change is part of issue #876 and addresses the use-set-for-membership check messages.

I’ll add the appropriate configuration to pyproject.toml in a separate PR later.

[tromai]

I wonder if this check flags an error on cases where you are performing a membership test in cases like this?

a: dict[str, str] = get_some_dictionary(...)
for key in a:
    ...

import glob

for filename in glob.iglob("*.txt"):
    print(filename)

a: list[str] = get_some_list(...)
for ele in a:
    print(ele)

Or does it only flag cases where we perform membership test on "statically-defined" lists

fruit in ["foo", "boo"]

[jenstroeger]

I wonder if […]

Why don’t you just try? 😉

@tromai, however, the code in your examples above are not membership tests: a for statement iterates over a collection, it does not check whether a given item exists in the collection.

[…] if this check flags an error on cases […]

Note also that these are not “errors” per se; the optional pylint checks are mostly recommendations for and improvements of code quality and performance.

See PR #890 on how to add the plugin; or, if you feel adventurous, you can read the checker’s code here

[tromai]

however, the code in your examples above are not membership tests: a for statement iterates over a collection, it does not check whether a given item exists in the collection.

Ah, thanks for pointing it out. I made some mistakes when coming up with the examples, please see the revised version here:

a: dict[str, str] = get_some_dictionary(...)
return if "key" in a.keys()
# OR: return if "key" in a

import glob

return "boo.txt" in glob.iglob("*.txt")

a: list[str] = get_some_list(...)
return "boo" in a

b = [1,2]
c: list[int] = get_int_list(...)
d = [4,3]
a = [b, c, d]

c in a

Note also that these are not “errors” per se; the optional pylint checks are mostly recommendations for and improvements of code quality and performance.

I should have been a bit more explicit in my wordings. I meant whether pylint would exit with an error/non-zero status code for those cases, but not about the content of the checks.