[vvhn]

>from APFS-normalization-preserving to APFS-native-normalization.

The developer documentation at [1]

seems to suggest that "native" normalization is normalization preserving as well and that native normalization is based on storing the hash of the normalized name instead of storing the normalized name itself.

" and preserves both case and normalization of the filename on disk in all variants. "

and

" APFS preserves the normalization of the filename and uses hashes of the normalized form of the filename to provide normalization insensitivity, whereas HFS+ stores the normalized form of the filename on disk to provide normalization insensitivity. "

edit - Even the linked blog post says the same thing

" macOS 10.13 will also support case-sensitive APFS, which will use native normalization. This is new in the developer beta. The filenames are still stored in the same way as prior APFS (not normalized like with HFS+), but APFS now uses normalization-insensitive hashes ... "

>how this unicode normalization messes up filenames and cause duplicates and stale copies when roundtripping

Being normalization preserving should fix that, right ?

1 https://developer.apple.com/library/content/documentation/Fi...