Unresolved Global - Ruff

What it does

Detects variables declared as global in an inner scope that have no explicit bindings or declarations in the global scope.

Why is this bad?

Function bodies with global statements can run in any order (or not at all), which makes it hard for static analysis tools to infer the types of globals without explicit definitions or declarations.

Example

Assigning without a global-scope declaration

python

def f():
    # unresolved global
    global x  # error
    x = 42


def g():
    print(x)  # unresolved reference

Use instead

Declare the global

python

x: int


def f():
    global x
    x = 42


def g():
    print(x)

Initialize the global

python

x: int | None = None


def f():
    global x
    x = 42


def g():
    print(x)