Hi Zsolt, A few small things.
In the non index case the new find_all_inheritors call returns the same list as the one right below it. You could reuse it there. For the docs I would write "are skipped with a warning". The last test, the parent with only foreign partitions, goes through the same code path as the one before it. I would drop it. Otherwise it looks good to me. Thanks Shihao
