[tz] Rule Russia incorrect

[Petr Machata]

Konstantin Kivi <konst at sirena2000.ru> writes:

> Time Zone Data v. 2011m (Released 24 October 2011)
> file contains a line
>
> ----------------------------------------------------------------------------------
> Rule    Russia  1993    2010    -   Mar lastSun  2:00s  1:00    S
> ----------------------------------------------------------------------------------
> which I believe means that last change to summer time was in 2010.
> This is incorrect, because this (2011) year we actually have changed
> time on last Sunday of March (by moving clock forward)
> I believe that for historical purposes the rule must looks as follows
> ----------------------------------------------------------------------------------
> Rule    Russia  1993    2011    -   Mar lastSun  2:00s  1:00    S
> ----------------------------------------------------------------------------------

You have to look a bit lower, where the Zone description takes place.
For example, Moscow contains the following:

Zone Europe/Moscow	 2:30:20 -	LMT	1880
                        [...]
			 3:00	Russia	MSK/MSD	2011 Mar 27 2:00s
			 4:00	-	MSK

So on Mar 27, Moscow stopped observing ruleset Russia, and instead
changed to permanent offset of +4:00.  It's done this way, because
permanent daylight saving is not really _saving_, it's simply a new
zone.

PM