[tz] Getting close to new release: testing, testing, ...

[random832 at fastmail.us]

On Wed, Sep 11, 2013, at 8:50, Zefram wrote:
> random832 at fastmail.us wrote:
> >We're getting stuck on ways to compatibly extend the current format.
> 
> Appending new fields to the existing format is a serviceable mechanism.
> The problem with glibc, and other tzfile parsers that are sensitive
> to such changes, is best addressed by giving advance notice of the new
> format before releasing the new zic.

My thinking is, If it's not going to actually be compatible with current
implementations, what's the point of being compatible at all?

> >What about adding another file in a new location,
> 
> I don't think there's any pressing need to do this, but it has its
> attractions.  If we do work on an incompatibly different file format, it
> should be a long-term project to produce a format to serve for the next
> 30 years, not a hasty process that we'd need to redo.  You've listed a
> couple of issues we could tackle this way, and I've got my own laundry
> list of desiderata.

I had been thinking about a PNG-like "chunk" structure  which would
allow implementations to ignore anything they don't understand. I
thought about proposing this back when we were talking about
tz-to-metazone mapping (something which I still think should belong to
this project rather than CLDR). That would take care of future
extensibility.