Nested ClusterableModel relations are not copied

[vbudovski-alliance]

Consider nested relations in the context of Band, Album, and Song models.

beatles = Band(name="The Beatles", albums=[
    Album(name="Please Please Me", songs=[
        Song(name="I Saw Her Standing There"),
        Song(name="Love Me Do"),
    ]),
])
beatles.save()

beatles_clone = Band("The Beatles 2020 comeback")
beatles.copy_all_child_relations(beatles_clone, commit=True)

Cloning the beatles object will not clone the songs attached to the album.

[vbudovski-alliance]

I was able to copy the nested records using:

        for child_object in source_manager.all().order_by("pk"):
            old_pk = child_object.pk
            # TODO: What do we do about the child_object_map of the child_object?
            if isinstance(child_object, ClusterableModel):
                child_object, _ = child_object.copy_cluster()

            child_object.pk = None
            setattr(child_object, parental_key_name, target.id)
            target_manager.add(child_object)

Not sure if this is the right solution or what to do about the nested child_object_map situation.