Python Binding not working correctly with multiple inheritance

[mbarger99]

I have a case like:

class MyClass(GravitySubscriber, GravityRequestor):
    def __init__(self):
        super(MyClass, self)__init__()

then I try to subscribe like:

self.gravityNode.subscribe("MySub", self)

That works, but then when I try to make an asynchronous request like:

self.gravityNode.request("MyService", reqGDP, self)

I get an error that the args are the wrong type or number. If I switch the order of the parent classes in the MyClass declaration, then the call to subscribe fails instead with the same message.

It looks like the problem is the type checking performed in the generated C++ code - for some reason it's only seeing that self is an instance of the first parent class, not the second.

[mbarger99]

The issue here is that swig does not support cooperative subclassing (i.e. generated Python classes to not call super in their __init__ methods).

We can look at adding this in the code generated here, but in the mean time there's an easy workaround: use the older style explicit calls to __init__ for each parent class. Instead of the code to initialize the MyClass class above, you'd have:

class MyClass(GravityRequestor, GravitySubscriber):
    def __init__(self):
        GravityRequestor.__init__(self)
        GravitySubscriber.__init__(self)