Nested Routes will fail with drf >v3.15.0

[jokiefer]

In v3.15.0 the register function will fail with nested routes, cause the basename will be checked.

def register(self, prefix, viewset, basename=None):
        if basename is None:
            basename = self.get_default_basename(viewset)

        if self.is_already_registered(basename):
            msg = (f'Router with basename "{basename}" is already registered. '
                   f'Please provide a unique basename for viewset "{viewset}"')
            raise ImproperlyConfigured(msg)

This will always raise ImproperlyConfigured exception if there are more then one nested routes based on the same root path.

example:

router.register(r'wms', service_views.WebMapServiceViewSet, basename='wms')
          .register(r'layers', service_views.NestedLayerViewSet, basename='wms-layers', parents_query_lookups=['service']),
    router.register(r'wms', service_views.WebMapServiceViewSet, basename='wms')
          .register(r'service-contact', metadata_views.NestedServiceContactViewSet, basename='wms-service-contact', parents_query_lookups=['service_contact_webmapservice_metadata']),
    

[auvipy]

thanks for the report. do you have plans for the fix?