[tz] Proposal: validation text file with releases

[Lester Caine]

On 15/07/15 06:09, Paul Eggert wrote:
>> I'm not sure this project fully
>> appreciates or understands the downstream impacts of changes on
>> systems other than zic.
> 
> It's helpful to mention those impacts on this list, if only clarify
> issues like these in the documentation.  Proposed patch attached.  This
> patch doesn't change zic's behavior; it just documents the way zic has
> always behaved.

I think that the only element of tzdist that is 'revolutionary' is that
in theory it should flag when an entry in tz has changed from that when
the previous enquiry was made. That a rule may have changed does not
necessarily mean that a particular enquiry has, so for instance adding
historic changes will not flag a change if the client system is only
asking for data say post 2000, or more critically for day to day use if
the transitions in the next 12 months have been subject to a change.

Picking up a previous quote ...
> and tzdist-format output (if we ever get around to doing that). 

tzdist NEEDS a fully populated set of data which will maintain every
published change in order that users can validate what they have
previously normalized against the current published data. That the
tzdist workgroup has no charter to provide that does beg the question
"What is the point?" without a freely available fully validated source
then tzdist is of little use?

-- 
Lester Caine - G8HFL
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