Re: [gnso-idn-wg] Re: Banning CCHH anywhere in a label
Sophia B wrote:
The decision is really upto the group. For myself, I think its okay - some sloppy programmers will have to re-program in the future, that's all - some, like Tina, felt they would deserve it....
I saw "sloppy programmers" mentioned several times and thought I'd weigh in.
As someone who has been involved in the development of IDN support in Mozilla and the ISC EchIDNA plug-in, I feel that it is highly unlikely that any programmer will have trouble with this. The reason for that is most applications will use one of the available IDNA libraries to handle IDNs. There are possibly two main pieces to IDN programming:
1. Converting input string into ACE for resolution
An application would search for non-ASCII characters anywhere in the string to detect IDN, and then pass the domain name into the IDNA ToASCII operation. The result will be punycode. I don't see a problem there. Should the programmer decide to implement the IDNA operations natively instead of using a library and gets it wrong, banning CCHH would not help anyway.
An application typically detects punycode by searching for a configurable prefix (set to "xn--" by default) anywhere in the string. Once punycode is detected, the string is passed into the IDNA ToUnicode operation. While it is quite possible that a false positive may arise if the programmer is not careful to ensure that the prefix only matches at the beginning of a label, the ToUnicode operation will return the same ASCII label if it is indeed simply a false positive. In any case, this should not cause any damage.
Therefore, it is my personal opinion that banning double hyphens is unnecessary.