Comment 6 for bug 197916

You can in theory use os.path.normcase to detect a case-insensitive filesystem (Windows, MacOS HFS+, Cygwin, OpenVMS). However IIRC that always returns a lowercase filename (uppercase on VMS if Python even runs on that platform) so to support most operations we also need to do a case-insensitive path2id call. That has the potential to get ugly pretty quickly performance-wise, I think; but it might be worth the tradeoff to get better behaviour.