[musl] Re: [tz] [musl] Re: Weird PST8PDT and EST5EDT behavior on Alpine Linux

[Russ Allbery <eagle@eyrie.org>]

Guy Harris <gharris@sonic.net> writes:
> On Mar 5, 2024, at 2:03 PM, Russ Allbery <eagle@eyrie.org> wrote:

>> It seems to support what I said: PST8PDT was supported, but :PST8PDT was not.

> Yes.  As I indicated, they didn't have tzdb code (if they did, that
> would be a surprise, as the tzdb project didn't exist in 1979/1980), and
> they didn't support any POSIX extensions to TZ (if they did, that would
> be a surprise as, at least according to
> https://en.wikipedia.org/wiki/POSIX, the first POSIX standard came out
> in 1988).

Ah, sorry, I had just misunderstood you.  Thank you for the confirmation
and reference!

Basically, to summarize, up until now I think it was possible to set TZ to
PST8PDT and have it work essentially everywhere, no matter how old the
edition of UNIX, thanks to the backward compatibility file in tzdata.  I
think musl may have been the first place where this broke somewhat
intentionally.  This is not a big deal and I'm not sure I'm arguing that
musl should change; I expect interfaces to change over time and it's
probably time to assume everyone supports the Olson identifiers.  But it
is a change in the portability landscape, if a minor one.  (Probably one
that's been around for a while and I just never noticed because I hadn't
been running the INN test suite on Alpine Linux.)

-- 
Russ Allbery (eagle@eyrie.org)             <https://www.eyrie.org/~eagle/>