undefined-name (F821)

Derived from the Pyflakes linter.

What it does

Checks for uses of undefined names.

An undefined name is likely to raise NameError at runtime.

def double():
    return n * 2  # raises `NameError` if `n` is undefined when `double` is called

Use instead:

def double(n):
    return n * 2

target-version: Can be used to configure which symbols Ruff will understand as being available in the builtins namespace.