nested_getattr — getattr for inner functions in decorators

nested.py

# coding: utf-8

from functools import wraps

def decorator_wraps(f):
    @wraps(f)
    def inner(*args, **kwargs):
        return f(*args, **kwargs)

    inner.test = 'ok'
    return inner

def outer_decorator_wraps(f):
    @wraps(f)
    def inner(*args, **kwargs):
        return f(*args, **kwargs)

    return inner


def decorator_non_wraps(f):
    def inner(*args, **kwargs):
        return f(*args, **kwargs)

    inner.test = 'ok'
    return inner

def outer_decorator_non_wraps(f):
    def inner(*args, **kwargs):
        return f(*args, **kwargs)

    return inner


@outer_decorator_wraps
@outer_decorator_wraps
@decorator_wraps
def func_wraps(*args, **kwargs):
    pass

@outer_decorator_non_wraps
@outer_decorator_non_wraps
@decorator_non_wraps
def func_non_wraps(*args, **kwargs):
    pass


def nested_getattr(func, name, *args):
   '''Get attr for nested functions'''
   if len(args) > 1:
       raise TypeError('nested_getattr expected at most 3 arguments, got {0}'.format(2 + len(args)))
   nested = func
   while 1:
       if hasattr(nested, name):
           return getattr(nested, name)
       if getattr(nested, 'func_closure', None) is None:
           if args:
               return args[0]
           raise AttributeError(name)
       nested = nested.func_closure[0].cell_contents


def test_not_fail_wraps():
    assert getattr(func_wraps, 'test') == 'ok'


def test_ok_wraps():
    assert nested_getattr(func_wraps, 'test') == 'ok'


def test_fail_non_wraps():
    assert not hasattr(func_non_wraps, 'test')


def test_ok_non_wraps():
    assert nested_getattr(func_non_wraps, 'test') == 'ok'