Re: [precis] Ambiguity in specification of case mapping in RFC 7613 and draft-ietf-precis-nickname

John C Klensin <john-ietf@jck.com> Tue, 27 October 2015 14:12 UTC

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Date: Tue, 27 Oct 2015 10:12:15 -0400
From: John C Klensin <john-ietf@jck.com>
To: Peter Saint-Andre <peter@andyet.net>, Tom Worster <fsb@thefsb.org>, Alexey Melnikov <Alexey.Melnikov@isode.com>
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Subject: Re: [precis] Ambiguity in specification of case mapping in RFC 7613 and draft-ietf-precis-nickname
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I am most of the way through a response now... should be able to
mail it within an hour or so if I'm not interrupted again; later
today in any event.
  
   john


--On Tuesday, October 27, 2015 07:52 -0600 Peter Saint-Andre
<peter@andyet.net> wrote:

> This issue has greater urgency now because
> draft-ietf-precis-nickname is now in AUTH48...
> 
> On 10/26/15 3:51 PM, Peter Saint-Andre - &yet wrote:
> 
>> After all that, I have 3 questions:
>> 
>> (1) Is my proposed text enough of a clarification that we
>> should make that change before the nickname I-D is published
>> as an RFC?
> 
> I think so.
> 
>> (2) Should we modify draft-ietf-precis-nickname so that case
>> folding is applied only as part of comparison and not as part
>> of enforcement? If so, should we make that change before this
>> document is published as an RFC?
> 
> Although it seems to be the case that Unicode case folding is
> primarily designed for the purpose of matching (i.e.,
> comparison), I have a concern that applying the PRECIS case
> mapping rule after applying the normalization and
> directionality rules might have unintended consequences that
> we haven't had a chance to consider yet. The PRECIS framework
> expresses a preference (actually a hard requirement) for
> applying the rules in a particular order. We made a late
> change to the username profiles (RFC 7613), such that width
> mapping is applied first (in order to accommodate fullwidth
> and halfwidth characters in certain East Asian scripts).
> Making a late change to the nickname profile also concerns me,
> even though both of these late changes seem reasonable on the
> face of it. I will try to find time to think about this
> further in the next 24 hours.
> 
>> (3) Should we update RFC 7613 so that case folding is applied
>> only as part of comparison and not as part of enforcement?
> 
> That is less urgent so I suggest that we address the nickname
> spec first.
> 
> Peter
>