Motivation

Python's default arguments are evaluated at definition as opposed to when the function is invoked. This leads to unexpected behavior, as mutations persist between calls. For a more detailed explanation, see The Hitchhiker's Guide to Python.

Example

def fnc(a, b={}):
    pass
foo.py:2:14: M511 - mutable default arg of type Dict

Installation

pip install flake8-mutable

Changes

[1.1.0] 2016-11-26

• Callables

[1.0.6] 2016-11-26

• added MANIFEST.in

License

MIT