pkg_resources get_provider return NullProvider where use egg without source

[LazyTricks]

if we install python egg without source, we will get _frozen_importlib.SourcelessFileLoader when call resource_isdir, and get NotImplementedError( "Can't perform this operation for unregistered loader type" )

how to solver it.

path DefaultProvider._register
before:

    @classmethod
    def _register(cls):
        loader_cls = getattr(
            importlib_machinery,
            'SourceFileLoader',
            type(None),
        )
        register_loader_type(loader_cls, cls)

after:

    @classmethod
    def _register(cls):
        loader_cls = getattr(
            importlib_machinery,
            'SourceFileLoader',
            type(None),
        )
        register_loader_type(loader_cls, cls)
        loader_cls2 = getattr(
            importlib_machinery,
            'SourcelessFileLoader',
            type(None),
        )
        register_loader_type(loader_cls2, cls)

then it works well.