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

[Paul Eggert]

On 3/5/24 12:12, Rich Felker via tz wrote:
> Yes, it's not clear to me (POSIX doesn't seem to specify) what the
> default rules should be when none are specified. However, it is clear
> that these strings meet the syntax for the POSIX TZ form, and thus
> musl does not attempt to interpret them as filenames, which could
> result in behavior contrary to the specified meaning.

Although TZDB interprets them as filenames, that is OK because the TZDB 
filenames have the specified meaning. Each TZDB Zone whose name has the 
form of a POSIX.1-2017 TZ string implements a set of transitions 
compatible with the corresponding POSIX TZ setting.

Long ago that wasn't the case: there were Zones like "GMT-12" that 
weren't compatible with POSIX even though their names took the POSIX 
forms. But that bug was fixed decades ago, in tzdata 94d (1994-02-24), 
and we no longer need to worry about that possibility.