nonlocal-without-binding (PLE0117)

Derived from the Pylint linter.

What it does

Checks for nonlocal names without bindings.

Why is this bad?

nonlocal names must be bound to a name in an outer scope. Violating this rule leads to a SyntaxError at runtime.

Example

def foo():
    def get_bar(self):
        nonlocal bar
        ...

Use instead:

def foo():
    bar = 1

    def get_bar(self):
        nonlocal bar
        ...

References

• Python documentation: The nonlocal statement
• PEP 3104 – Access to Names in Outer Scopes