Updating RFC 5890-5893 (IDNA 2008) to Full Standard
Mark Davis ☕
mark at macchiato.com
Fri Nov 16 03:22:57 CET 2012
concerns --> important concerns
*— Il meglio è l’inimico del bene —*
On Thu, Nov 15, 2012 at 5:27 PM, John C Klensin <klensin at jck.com> wrote:
> --On Thursday, November 15, 2012 15:56 -0800 Mark Davis ☕
> <mark at macchiato.com> wrote:
> > Anne,
> > The development of IDNA2008 was a long, painful, and
> > frustrating process, with a split between:
> > - people who were concerned with backwards compatibility
> > and what would happen during a migration period (such as
> > most representatives to the Unicode consortium, and
> > - people who did not feel that it was a concern (such as
> > John, the other authors, and most participants in the WG).
> > The rough consensus of the WG was judged to be that backwards
> > compatibility and migration were not concerns, and that's what
> > went into idna2008.
> Certainly there was a disagreement in the WG about which
> objectively to prioritize. However, characterizing the people
> who disagreed with you as feeling "that backwards compatibility
> and migration were not concerns" doesn't seem accurate to me.
> Instead, many of us felt that they _were_ concerns, but that we
> saw engineering/design tradeoffs between preserving
> compatibility with whatever had been done under the IDNA2003
> umbrella and other concerns, including:
> (1) The higher degree of identifier (including URL) stability
> and predictability that would result from a strict one-one
> relationship between (in IDNA2008 terms) A-labels and U-labels
> was an advantage and that the difficulties that had arisen from
> the lack of that relationship in IDNA2003 was a concern.
> (2) Some of the incompatible changes made in IDNA2008, including
> permitting ZWJ and ZWNJ rather than discarding them and allowing
> some characters that IDNA2003 had mapped away were significant
> and that preserving the IDNA2003 behavior instead of allowing
> them was a consideration.
> (3) Because IRIs were not part of HTTP and were not even
> specified until late 2004, at least some of us did not believe
> that the use of native character strings in URLs represented
> particularly good practice. The amount of incompatibility
> between URLs that conformed to IDNA2003 but (or and) that
> contained Punycode-encoded labels was much less than that for
> pseudo-URLs that contained native character ("Unicode") strings.
> (4) We also expected that the Internet would continue to grow
> and that the number of users and web pages that would be
> adversely affected by the change would be proportionately far
> fewer relative to the total by 2020, or even 2012, than they
> were in 2008. Of course, from that point of view, the longer
> those who design web pages and the tools they use are told that
> IDNA2003-like conventions will work for the indefinite future,
> the larger the proportion of pages that do not conform strictly
> to IDNA2008 will linger. We recognized the tradeoff that
> implied as well. You will recall multiple questions about what
> the conditions were for stopping and converting if UTR 46 were
> On balance, the WG considered all of those factors and made the
> choice -- more difficult for many of us than might have been
> obvious in those painful discussions -- that tolerating some
> incompatibility to get the advantages it would bring was
> preferable to preserving the IDNA2003 behavior, and even
> providing continuing support for non-conforming URLs.
> Reasonable people can disagree with that decision, but nothing
> about it implied that the issues on the other side of the
> tradeoff were "not concerns".
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