Re: [tz] Ubuntu drops old-style links

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Mar 20 14:59, Brian Inglis via Cygwin-apps wrote:
> On 2024-03-19 02:19, brian.inglis@systematicsw.ab.ca wrote:
> > On 2024-03-18 21:12, Matt Johnson-Pint via tz wrote:
> > > I just learned that Ubuntu Noble (24.04) decided to intentionally
> > > split the tzdata package.  Old-style links such as US/Eastern are no
> > > longer included by default, but are available in the tzdata-legacy
> > > package instead.
> > > 
> > > Just thought I'd share.  I wonder if other distributions / platforms
> > > / libraries will follow suit.  What do y'all think?
> > > 
> > > See:
> > > <https://bugs.launchpad.net/ubuntu/+source/tzdata/+bug/2058249>
> > > <https://stackoverflow.com/questions/78180695/unrecognized-time-zone>
> 
> > I've been looking at that to reduce Cygwin CI and embedded build server
> > setup overhead by limiting base install data to:
> > 
> > - only the zones in zonenow.tab;
> > - optionally those in zone1970.tab not in zonenow.tab;
> > - additionally those in zone.tab in backward, and/or backzone;
> > - possibly those not in zone.tab, only in backward, and/or backzone;
> > - additions those in posix subtree, or right subtree.
> 
> As tzdata maintainer, I would like to discuss on this list first, to take
> advantage of a wide variety of experience in different environments with
> different practices and requirements, before making more definite proposals
> on the public list.
> 
> Please see the attached log for prioritized subsets of tzdata for consideration:
> [...]
> What would the impact on tzset conversion from Windows to Olson tzdb be?
> We would probably have to add all of these in to any minimal install.
> I think I looked at that somewhere, sometime, not too long ago.

We're generating the conversion from Windows to POSIX timezone via
the conversion table from unicode.org:

https://cygwin.com/cgit/newlib-cygwin/tree/winsup/utils/tzmap-from-unicode.org

Plus a few (7, actually) mappings the Unicode consortium missed in
the list (or maybe they are available in the meantime, needs checking).
This is the minimum list of timezone info we need in the tzdata DB.

Corinna