TZ changes for Brazil for 2003/2004

[Paul Eggert]

At 20 Sep 2003 08:24:57 -0300, Vitor de Matos Carvalho writes:

> I saw that in the archive zone.tab exists America/Fortaleza,
> America/Recife, America/Maceio, I suggest to make one alone
> something as America/Bahia Ilhéus NE Brazil (BA, SE, AL, PE, PI, CE,
> RN, PI, MA), instead of having some entrances for some states of the
> NE of the Brazil, would only join everything in one, in view of that
> no state of the NE will have hourly of summer.

If I understand you correctly, you are suggesting that instead of giving
the user these choices for Brazil:

   Atlantic islands
   Amapa, E Para
   NE Brazil (MA, PI, CE, RN, PR)
   Pernambuco
   Tocantins
   Alagoas, Sergipe
   Bahia
   S & SE Brazil (GO, DF, MG, ES, RJ, SP, PR, SC, RS)
   Mato Grosso do Sul
   Mato Grosso
   W Para, Rondonia
   Roraima
   E Amazonas
   W Amazonas
   Acre

we simplify matters, and give only these choices:

   Atlantic islands
   east Brazil without daylight-saving time (DST)
     (AL, AP, BA, CE, MA, East PA, PB, mainland PE, PI, RN, SE, TO)
   east Brazil with DST (DF, ES, GO, MG, PR, RJ, RS, SC, SP)
   central Brazil without DST (east AM, MT, west PA, RO, RR)
   central Brazil with DST (MS)
   western Brazil (AC, west AM)

That would indeed be simpler for users that care only about current
and predicted future timestamps.  But it would mishandle timestamps in
the recent past.  For example, if you lived in Mato Grosso and chose
central Brazil without DST, your files dated January 2003 would have
time stamps that were off by one hour, since MG observed DST last year
but not this year.