Question

I am using the Borg pattern with mutual inclusion of modules. See the example code (not the real code but it shows the problem) below. In this case, I have two different Borgs because the class names (and I guess the class) are seen as different by the interpreter.

Is there a way to use the Borg in that case without reworking the module architecture?

Module borg.py

import borg2

class Borg:
    _we_are_one = {}

    def __init__(self):
        self.__dict__ = Borg._we_are_one
        try:
            self.name
        except AttributeError:
            self.name = "?"
        print self.__class__, id(self.__dict__)

def fct_ab():
    a = Borg()
    a.name = "Bjorn"

    b = Borg()
    print b.name

if __name__ == "__main__":
    fct_ab()
    borg2.fct_c()

Module borg2.py

import borg

def fct_c():
    c = borg.Borg()
    print c.name

The result is

__main__.Borg 40106720
__main__.Borg 40106720
Bjorn
borg.Borg 40106288
?

In order to clarify my problem:
Why does Python consider __main__.Borg and borg.Borg as two different classes?

Answer 1

The problem only occurs in your main-function. Move that code
to its own file and everything is as you’d expect. This code

import borg
import borg2

if __name__ == "__main__":
    borg.fct_ab()
    borg2.fct_c()

delivers this output:

borg.Borg 10438672
borg.Borg 10438672
Bjorn
borg.Borg 10438672
Bjorn