Can a base class know if a method has been overridden?

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On Sep 24, 5:23 pm, Ratko <rjago... at gmail.com> wrote:
> Hi all,
>
> I was wondering if something like this is possible. Can a base class
> somehow know if a certain method has been overridden by the subclass?
> I appreciate any ideas.
> Thanks,
>
> Ratko


The first time I used Zope, I immediately had an issue of overriding a
predefined
methods without knowing it (there were 400+ methods inherited from
dozens of base
classes). So I wrote this utility:


def check_if_I_am_overriding_names():
    """Prints a message if we are overriding a name. Useful for
framework
    beginners. Example in Zope:

    >> from OFS.Folder import Folder
    >> class MyFolder(OFS.Folder):
    ..    check_if_I_am_overriding_names()
    ..    id = 'pippo'
    ..
    AlreadyDefinedNameWarning: id
    """

    def makecls(name, bases, dic):
        for nam, val in dic.iteritems():
            if nam.endswith("__") or nam == "meta_types":
                # ignore redefinitions of special names
                # and redefinition of meta_types (for Zope code)
                continue
            any_base_has_name = [base for base in bases
                                 if hasattr(base, nam)]
            if any_base_has_name:
                print "AlreadyDefinedNameWarning: " + nam
        return type(name, bases, dic)

    f = sys._getframe(1)
    f.f_locals["__metaclass__"] = makecls

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