Another round of IDNAv2, and thoughts on IDNA2008 goals

Paul Hoffman phoffman at
Wed Mar 4 23:16:04 CET 2009

At 10:48 PM +0100 3/4/09, Simon Josefsson wrote:
>Paul Hoffman <phoffman at> writes:
>> I do not pretend that IDNAv2 is wonderful. It has all of the cut
>> corners and compromises that we made in IDNAv1. I would not be
>> surprised if the WG decided that fixing those in IDNA2008 is the
>> better way to go, even if it means introducing new problems, but I
>> would also not be surprised if the WG said "let's just go with IDNAv2
>> now" and be willing to do IDNAv3 in a few years. If the WG goes with
>> IDNAv2, I certainly don't think we should wait six years for IDNAv3;
>> it should be much sooner than that.
>I think IDNAv2 is a good idea, to resolve several important problems in
>IDNAv1 in a guaranteed backwards compatible way, but I wouldn't want to
>delay IDNA2008 significantly.  However, I don't think that is required.
>IDNAv2 can be reviewed and deployed relatively quickly.

I am not sure what you are saying here, but I want to be clear: if the WG decides to move forwards with IDNA2008, there is no reason to do IDNAv2. I see it as an "either or" situation.

>One question: do you think there are input strings that are not allowed
>by IDNAv1 but will be allowed by your IDNAv2 that will be encoded
>differently in IDNAv2 compared to IDNA2008?  I am aware that ezset may
>be one example, but I'm looking for other examples.

Your phrase "are not allowed by IDNAv1" needs to be better defined. Esszet *is* allowed by IDNAv1: it is mapped to "ss". In the current drafts of IDNA2008, four characters have that property in common: Esszet, Greek final sigma, ZWJ, and ZWNJ.

>If there are many examples of these strings, rather than the few
>exceptions like ezset, I think we are better of discussing whether to
>completely abandon either IDNAv2 or IDNA2008, since making
>IDNAv1+IDNAv2+IDNA2008 work together will be a complex task.

I do not want a world with IDNAv1+IDNAv2+IDNA2008; it should either be IDNAv1+IDNAv2 or IDNAv1+IDNA2008. I deeply apologize for not making that clearer.

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