> On Mar 23, 2017, at 12:24 PM, David Duncan <david.dun...@apple.com> wrote: > > I just want to remind everyone I’m *not* a file system’s engineer – I’m just > trying to help Dave (and anyone else caught in this) make sure their app can > find their files. > >> On Mar 23, 2017, at 1:53 AM, Alastair Houghton >> <alast...@alastairs-place.net> wrote: >> >> On 22 Mar 2017, at 18:00, David Duncan <david.dun...@apple.com> wrote: >>> >>> So there was another explanation posted on the bug that I’m not certain you >>> got, but which I think may explain. >>> >>> Basically the concept is that since APFS doesn’t normalize file names, if >>> you store file names in some other storage (say in your preferences) then >>> what could happen is this: >>> >>> 10.2: File is saved with a file name handed to the file system in NFC form. >>> File system converts the file name to NFD. You store it as NFC. >>> 10.3: File system is converted to APFS, and the file name is NFD. You try >>> to look up the file as NFC, and it fails. >> >> This is going to cause problems, though, when things migrate from HFS+ to >> APFS, because the HFS normalisation *isn’t* a standard one. In particular, >> it certainly *isn’t* NFD for the current version of Unicode. > > Yes, that is the crux of Dave’s issue – HFS+ => APFS only translated the file > names (from UTF-16 to UTF-8), it did not re-normalize them. > >> The only obvious solution for that would be to have the HFS+ to APFS >> migration tool *re-normalise* the filenames (maybe it does?), but that’s >> bound to break things in the (presumably quite common) case where the >> filename stored in e.g. a plist was originally obtained from the filesystem. > > Arguably there is no way for the file system converter to know how it should > renormalize file names. This is akin to case sensitive vs case insensitive > file systems. If you ran a converter from a case insensitive file system to a > case sensitive one, you could preserve the capitalization during the > conversion, but file lookups that used the wrong case would fail after the > conversion. But the converter can’t know you want to look up “foo” via “FOO” > or “Foo” to do any kind of normalization. The difference here is that for the > most part unicode normalization is invisible to the developer. > >> >> Kind regards, >> >> Alastair. >> >> -- >> http://alastairs-place.net >> > > -- > David Duncan
I appreciate the help you (and everyone else) has given. I should be able to add an option to rescan what files are there. And I'll make time this weekend to submit a DTS incident and see what answer I can get and share it here. I do suspect I won't be the only one bit by this. Thanks, Dave Reed _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
