Hey @serhiy-storchaka, I believe you're pretty familiar with the pathlib internals. Penny for your initial impressions of this patch? It does cut out a key part of the initial pathlib design: the idea of skipping re-parsing and re-normalizing paths in case where we can be sure it's not necessary (e.g. in path.parents, path.iterdir()). I'd love to be able to convince you this is a good idea!