use-implicit-booleaness-not-comparison-to-zero / C1805

Message emitted:

"%s" can be simplified to "%s", if it is strictly an int, as 0 is falsey

Description:

0 is considered false in a boolean context. Following this check blindly in weakly typed code base can create hard to debug issues. If the value can be something else that is falsey but not an int (for example ``None``, an empty string, or an empty sequence) the code will not be equivalent.

Caution

This message is disabled by default. To enable it, add use-implicit-booleaness-not-comparison-to-zero to the enable option.

Problematic code:

def important_math(x: int, y: int) -> None:
    if x == 0:  # [use-implicit-booleaness-not-comparison-to-zero]
        print("x is equal to zero")

    if y != 0:  # [use-implicit-booleaness-not-comparison-to-zero]
        print("y is not equal to zero")

Correct code:

def important_math(x: int, y: int) -> None:
    if not x:
        print("x is equal to zero")

    if y:
        print("y is not equal to zero")

Configuration file:

[main]
enable=use-implicit-booleaness-not-comparison-to-zero

Created by the refactoring checker.