[tz] [PATCH 0/1] Add Asia/Beijing

Derick Rethans tz at derickrethans.nl
Thu Aug 16 07:44:29 UTC 2012

On Wed, 15 Aug 2012, David Patte ₯ wrote:

> Thanks for the research and spreadsheet. It is very useful.
> Being Canadian, I am intruiged by Ottawa, which is the capital of Canada, the
> second largest city in Ontario, and the fourth largest in Canada. It seems
> that since 1970, Ottawa and Toronto and Montreal have followed the same
> timezone/saylight saving rules, but prior to that, Ottawa and environs was
> likely more in sync with Montreal's daylight saving rules than Toronto's rules
> for proximity and commercial reasons. As well, Montreal, not Toronto, was the
> largest city in Canada until about 1975.
> So, as far as I understand the rules, Ottawa does not require a link in tz at
> this time - but if a link for capitals is ever added in tz - the preferred
> link for Ottawa should probably be Montreal, not Toronto.

This IMO partly illustrates why we should not make any links. The idea 
is that TZ identifiers are unique and *stable*. In the list, there are 
plenty of IDs with as comment "Used to be the capital until 19xx". 
In the case of Ottawa and Montreal, if you add a link, and then Quebec 
decides to split off Canada and choses to use Europe/Paris (which is not 
that far sought ;-) ) then you end up having a non-stable ID as Ottawa 
and Montreal no longer can be linked.

The issue of Beijing/Shanghai has been discussed many times, and I feel 
that we shouldn't revisit it anymore. TZIDs are not meant to be used in 
userland - this is document. Unicode's CLDR 
(http://unicode.org/repos/cldr-tmp/trunk/diff/summary/de.html, search 
for "AT/Vienna", "Europe/​London" f.e., as well as 
already provide user-visable 
names for many languages and timezones - and this would be the perfect 
place for all sorts of display rules.


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