The TRANSITIONAL proposal (was: The real issue: interopability, and a proposal)

Andrew Sullivan ajs at
Tue Dec 1 19:15:48 CET 2009

On Tue, Dec 01, 2009 at 09:49:10AM -0800, Mark Davis ? wrote:
> When reading some of the transition proposals, one approach occurred to me.
> What if we have a new status for the 4 characters: TRANSITIONAL?


> That will cause currently valid URLs to fail, but that is far better than
> having them have ambiguous targets. This way we get to the long-term goal of
> having these characters be PVALID, without having the disruption during the
> interim.

I like this distinction between "failure incompatibility" and
"ambiguous incompatibility": it strikes right at the heart of the

If the proposal were to go ahead (i.e. we were to add a TRANSITIONAL
status), then it solves a few problems:

    1.  The rest of the (less-controversial) changes can go ahead.

    2.  The problem is not "baked in" for all time (i.e. we signal now
    that a change will be coming).

    3.  We get some time perhaps to invent a way to deal with the
    transitional characters.

    4.  We get a new mechanism by which we can solve a future problem
    of this sort were one, heavent forfend, to show up.

So I think this could be a fruitful direction.  My only hesitation is
the possibility that we'd end up in exactly the same position in a few
years, because someone decided to do fancy client-based mapping in an
effort to produce backward compatibility with IDNA2003.  Would we have
the will at that point to say, "Too bad, we told them not to do that"?


Andrew Sullivan
ajs at
Shinkuro, Inc.

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