[tz] tzid in zoneinfo?

[Steven R. Loomis]

Dear TZ list,

 I would like to propose that zic-compiled binaries (such as what shows
up in /etc/zoneinfo) include the tzid (such as ‘America/New_York’).


 I work on the ICU project (Unicode’s International Components for
Unicode) and also CLDR (Unicode’s Common Locale Data Repository).  The
ICU library consumes tz data, and uses the localized data from CLDR to
(among other things) display translated time zone names of various
sorts, and format different types of dates.
 
 A perpetual problem is trying to detect the actual timezone of a
platform. Ideally something like the TZ variable is set to a valid tz id
such as America/New_York which we can use directly.  Otherwise, we try
various approaches - including trying to resolve /etc/localtime’s
symlink to see if it points to a file which appears to be in some sort
of zic-compiled tree. This brings up bugs such as
http://bugs.icu-project.org/trac/ticket/12770 because various platforms
use different paths as the targets of /etc/localtime - and some times,
it's a doubly linked symlink.  In other cases, the file is just copied,
and we have to trawl through /usr/share/zoneinfo looking for a binary
file which matches.  There are other methods employed if these fail, but
I think this will suffice for our purposes.
 
 Even if ICU consumed the /etc/zoneinfo file directly, or was able to
call the host to perform the calculations it needs, that would not
suffice in terms of localized content.  As I think has been noted on
this list before, it does not seem to be a goal of the tz database to
collect these translated names, and tz-link.html does link to CLDR as
one possible source of translations.
 
 I think that this would benefit other users as well, by making zone
files self identifiable. I think the JDK has to do similar analysis. 
Some JavaScript containers (Mozilla especially) now support IANA tz ids,
such as in
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DateTimeFormat#Parameters

 Any thoughts or comments?
 
 Thanks,
   Steven


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