Question

Having the following code, what can I do with the ‘foo’ function to make it unbound in any case even if it is assigned to class attribute? Overriding __get__ doesn’t help – as far as I understand because it is not used when function is absent from __dict__ of an instance (it is so in case of class attributes).
But what else can be done here?

def foo(x):
    print(x)

def foo_get(self, obj, type=None):
    return foo

foo.__get__ = foo_get

class A(object):
    def __init__(self):
        self.f = foo
class B(object):
    f = foo


a = A()

print(a.f)               #<function foo at 0x2321d10>
print(a.f.__get__(a, A)) #<function foo at 0x2321d10>

b = B()

print(b.f)               #<bound method B.foo of <__main__.B object at 0x23224d0>>

Answer 1

I’m pretty sure you want @staticmethod.

foo = staticmethod(foo)

You can also define __get__ on a callable class:

class Foo(object):
    def __get__(self, obj, type=None):
        return self

    def __call__(self, x):
        print(x)

foo = Foo()

class A(object):
    def __init__(self):
        self.f = foo
class B(object):
    f = foo


foo(1) # 1
a = A()

a.f(1) # 1
print(a.f)               #<function foo at 0x2321d10>
print(a.f.__get__(a, A)) #<function foo at 0x2321d10>

b = B()
b.f(1) # 1


print(b.f)               #<__main__.Foo object at 0x7fa8c260be10>

It’s one extra level of indentation and a few extra lines of code, but that’s how it can be done, if it’s important.