[JDK 8] Code review request JDK-8023881, IDN.USE_STD3_ASCII_RULES option is too strict to use Unicode in IDN.toASCII

[Michael McMahon]

Xuelei,

This looks fine.

I would add a comment to line 408-409 that says something like:

Non LDH refers to characters in the ASCII range, but which
are not letters, digits or the hypen.

That explains what exactly was fixed here.

Michael

On 29/08/13 13:46, Xuelei Fan wrote:
> Hi,
>
> Please review the fix of JDK-8023881.
>
> webrev: http://cr.openjdk.java.net/~xuelei/8023881/webrev.00/
>
> This bug has not been ported to bugs.sun.com.  The following is the
> descirption of the issue.
>
> --------------------------------------------------------
> IDN.toASCII("示例.com", IDN.USE_STD3_ASCII_RULES) throws:
>
> Exception ... java.lang.IllegalArgumentException: Contains non-LDH
> characters
> at java.net.IDN.toASCIIInternal(IDN.java:275)
> at java.net.IDN.toASCII(IDN.java:118)
>
> However, the "idn" tool is able to handle above IDN properly:
> $ idn --usestd3asciirules www.示例.com
> www.xn--fsq092h.com
>
> Per step 3, section 4.1, RFC 3490:
>
>     3. If the UseSTD3ASCIIRules flag is set, then perform these checks:
>
>       (a) Verify the absence of non-LDH ASCII code points; that is, the
>           absence of 0..2C, 2E..2F, 3A..40, 5B..60, and 7B..7F.
>
>       (b) Verify the absence of leading and trailing hyphen-minus; that
>           is, the absence of U+002D at the beginning and end of the
>           sequence.
>
> However, in the impl of IDN is checking far more strictly than above.
> Unicode point bigger than 0x007A is not acceptable.  It is too strict to
> convert Unicode with IDN.toASCII() if IDN.USE_STD3_ASCII_RULES option is
> set.
> --------------------------------------------------------
>
> Thanks,
> Xuelei