Re: [weirds] Ted Lemon's Discuss on draft-ietf-weirds-rdap-query-16: (with DISCUSS and COMMENT)

[Ted Lemon <[e-mail]>]

On Oct 29, 2014, at 7:53 PM, Pete Resnick <[e-mail]> wrote:
> A client that does the right thing and only queries all-a-label or all-u-label strings is going to get consistent results, because it is taking responsibility to do the appropriate mappings. But if the client is blindly handing over labels it got from somewhere else (which is why you would get mixed stuff),

Why would the client do that?   Why not specify what the right thing is for the client to do as a SHOULD, and _then_ explain what might break if it doesn't, rather than just sort of talking about it and hoping for the best?

Also, U-labels are case-sensitive.   So the semantic difference you're describing doesn't actually exist.   A-labels are just encoded U-labels.   So if you take an A-label and turn it into a U-label, you can do a comparison between it and another U-label without case folding, and indeed you aren't _allowed_ to do case folding.   And similarly, if you take a U-label and encode it as an A-label, then you can just compare it to other A-labels, because A-label comparisons are case-insensitive with respect to the A-label representation: case-folding does not change the meaning of an A-label.   This is explained in RFC 5891 section 3 bullet point 2.

(BTW, what I just explained in the above paragraph gives me a headache and tells me we should _never_ use IDN for any writing system that has case, because it will be insanely easy to spoof.   But you probably already knew that.)