[tz] Proposal: validation text file with releases

[Martin Burnicki]

Stephen Colebourne wrote:
> On 15 July 2015 at 00:51, Paul Eggert <eggert at cs.ucla.edu> wrote:
>> Jon Skeet wrote:
>>> Unfortunately dump doesn't have all the information I'd wish it to -
>>> namely
>>> the split between standard and daylight offsets. It indicates whether a
>>> zone is in daylight savings or not, but not how much that contributes to
>>> the overall offset.
>>
>> That shouldn't matter.  No software should care about that.  Any software
>> that does care is delving into undocumented and unsupported areas.
>
> The published API of Joda-Time and JSR-310 exposes the difference
> between the base offset and the current offset (including DST). Its
> this kind of detail that makes them much more useful. To say that
> software should not care and that it is unsupported is .... er ....
> rather worrying.

I'd also appreciate if we could get more details out of the TZ db in an 
easy way. We (Meinberg) also have embedded devices (not POSIX, not even 
an OS, just a microcontroller) which also does conversion from UTC to 
local time, and it would be a very nice feature if a program could 
easily extract all information for a given year (i.e. standard and DST 
offsets, beginning and end of DST, if any) from a TZ file after this has 
been updated.

> I think I've indicated before that I'm not sure this project fully
> appreciates or understands the downstream impacts of changes on
> systems other than zic. I think Jon's proposals would help to make the
> impacts much clearer.

Again, I fully agree and also support Jon's proposal.

Martin