Feature request - invoke any/all on non iterables #10404
Description
Current problem
Probably an extension to the existing not-an-iterable error message.
Looks pretty trivial, but could be very useful in cases we want to run any or all on a generator or list that is a return value of a function call that might also return None (e.g. in a side/error case). Running any(None) or all(None) causes Python to crush, the user might think the code is okay, without ever running the None case, and the error is discovered only in a later stage.
Pylint shows no errors (as far as I am concerned) for:
all(None)
any(None)
def create_list():
if error_case():
return None
return [1, 2, 3]
all(create_list())
any(create_list())
for _ in create_list():
pass
Desired solution
I think we have here 2 cases:
- We know the value is non-iterable, then it is just an expansion of
not-an-iterableforanyandall. Since this also invokesnot-an-iterable:
for _ in None:
pass
Error description: same as in not-an-iterable: Non-iterable value %s is used in an iterating context .
- In some cases we know the value is non-iterable, then we need an extended logic that could also be applicable to using the
forkeyboard, e.g.:
def create_list():
if error_case():
return None
return [1, 2, 3]
for _ in create_list():
pass
Error description: might be the same error name as not-an-iterable, but with different description: Non-iterable value %s might be used in an iterating context (emphasis on the might).
Additional context
Maybe there are more cases of a built in function that causes iteration apart from all/any/for. Note that we might want to split this issue into 2 issues:
- Extension of
not-an-iterabletoanyandallkeyword. - Enhancing
not-an-iterableimplementation to include cases where we know the value could be non-iterable.