On Jan 21, 2008, at 11:48 AM, David Kastrup wrote:

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> Kevin Ballard <kevin@sb.org> writes:
>
>> On Jan 21, 2008, at 9:14 AM, Peter Karlsson wrote:
>>
>>> I happen to prefer the text-as-string-of-characters (or code points,
>>> since you use the other meaning of characters in your posts), =20
>>> since I
>>> come from the text world, having worked a lot on Unicode text
>>> processing.
>>>
>>> You apparently prefer the text-as-sequence-of-octets, which I tend =20=

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>>> to
>>> dislike because I would have thought computer engineers would have
>>> evolved beyond this when we left the 1900s.
>>
>> I agree. Every single problem that I can recall Linus bringing up =20
>> as a
>> consequence of HFS+ treating filenames as strings is in fact only a
>> problem if you then think of the filename as octets at some point. If
>> you stick with UTF-8 equivalence comparison the entire time, then
>> everything just works.
>
> git calculates hashes over filenames and sorts them.  This is not a =20=

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> mere
> question of "UTF-8 equivalence comparison".

No, it's a question of hashing algorithm. And it's one that's fairly =20
easily solved simply by picking a specific nonambiguous UTF-8 encoding =20=

before hashing.

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>> Granted, this is a problem when you have to operate on a filesystem
>> that thinks of filenames as octets,
>
> It also is a problem when operating on a filesystem that considers =20
> "=E4" a
> single utf-8 character instead of decomposing it.

What makes you say that?

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>> but as I said before, this doesn't mean the HFS+ approach is wrong, =20=

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>> it
>> just means it's incompatible with Linus's approach.
>
> It is not the business of a file system to juggle with filename
> representations.

You're right, that probably belongs in the VFS layer, but the behavior =20=

is the same either way. You can't leave it up to user-space libraries =20=

to enforce a filesystem encoding, because you can't rely on all =20
clients to behave properly.

-Kevin Ballard

--=20
Kevin Ballard
http://kevin.sb.org
kevin@sb.org
http://www.tildesoft.com