[Interface-dev] overriding InterfaceClass.__call__ and 3.4.2dev

[Jean-Paul Calderone]

Hey,

I just noticed a change between 3.4.1 and 3.4.2dev relating to the __call__
method of InterfaceClass.  If you override it in 3.4.1, it will be used.  If
you override it in 3.4.2dev, it won't be.

Is this an intentional change?  It breaks a feature of Twisted (in web2).  I
believe the relevant code which is no longer being invoked is this:

# Is there a better way to do this than this funky extra class?
_default = object()
class SpecialAdaptInterfaceClass(interface.InterfaceClass):
    # A special adapter for IResource to handle the extra step of adapting
    # from IOldNevowResource-providing resources.
    def __call__(self, other, alternate=_default):
        result = super(SpecialAdaptInterfaceClass, self).__call__(other, alternate)
        if result is not alternate:
            return result

        result = IOldNevowResource(other, alternate)
        if result is not alternate:
            result = IResource(result)
            return result
        if alternate is not _default:
            return alternate
        raise TypeError('Could not adapt', other, self)
IResource.__class__ = SpecialAdaptInterfaceClass

You can find this in twisted/web2/iweb.py if you want.

Was this accidental?

Jean-Paul