[tz] Java & Rearguard

[Florian Weimer]

* Paul Eggert:

> On 5/30/19 2:14 AM, Stephen Colebourne wrote:
>> It is a compatibility requirement of the main Java libraries
>> (including icu4j IIUC) that DST is always positive.
>
> Where is this documented? And what do the main Java libraries do in an
> environment where the DST offset is negative? For example, if I run
> the following shell command on a POSIX-compatible host:
>
> TZ='IST-1GMT0,M10.5.0,M3.5.0/1' java [arguments]
>
> can you give an example of what goes wrong and why? This command gives
> Java the rules that Ireland has used since 1996, with Irish Standard
> Time (1 hour ahead of GMT) used in the summer and GMT (a "negative
> daylight saving time") in the winter.

Is this really the right example?  I would have expected something
negative after the slash.

Thanks,
Florian