redefined-builtin / W0622

Message emitted:

Redefining built-in %r

Description:

Used when a variable or function override a built-in.

Problematic code:

def map():  # [redefined-builtin]
    pass

Correct code:

def map_iterable():
    pass

Additional details:

The allowed-redefined-builtins option lets you specify names that are permitted to shadow built-ins.

However, this option is not effective for redefinitions at the module level or for global variables. For example:

Module-Level Redefinitions:

# module_level_redefine.py
id = 1  # Shadows the built-in `id`

Global Variable Redefinitions:

# global_variable_redefine.py
def my_func():
    global len
    len = 1  # Shadows the built-in `len`

Rationale:

Shadowing built-ins at the global scope is discouraged because it obscures their behavior throughout the entire module, increasing the risk of subtle bugs when the built-in is needed elsewhere. In contrast, local redefinitions are acceptable as their impact is confined to a specific scope, reducing unintended side effects and simplifying debugging.

Created by the variables checker.