[tz] Proposal: validation text file with releases

[Paul Eggert]

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.

> As for platforms that don't use the tz database at all - as the purpose of
> this is to validate the use of the tz database, I'm not sure that's much of
> an advantage.

It can be helpful, for example, when comparing a simple tz database entry to the 
should-be-equivalent POSIX TZ string (which does not require the tz database).

> I haven't yet got a feeling for your thoughts on the proposal... is this
> something you can see any future in? I suppose the canonical file wouldn't
> *have* to come from IANA, but that does feel like the best option.

I can see something along these lines working, yes.  That is, we could 
distribute extra tarballs containing zdump output (with a better format 
perhaps), zic output, and tzdist-format output (if we ever get around to doing 
that).