Brazil zoneinfo corrections.

[Rodrigo Severo]

You see, it has been a good way to understand a little better the tz 
format. And a nice patience exercise also :)

Paul Eggert wrote:
> Thanks for your proofreading of the history of time zones and daylight
> saving time of Brazil.  Here are some thoughts about your comments.
> 
> 
>>From: Rodrigo Severo [mailto:rodrigo.lists at fabricadeideias.com] 
>>Sent: Thursday, October 16, 2003 7:31 PM
> 
> 
>>1. The effects of decrees 52700 (1963-10-18) and 53071 (1963-12-03) 
>>weren't correctly represented by the data as what they really have done 
>>was to make a set of states start DST at 1963-10-23 00:00 and the rest 
>>of the country to start DST at 1963-12-09 00:00.
> 
> 
> As far as I can see, the current tz data does that.  The tz source
> looks different from what you're proposing, but the actual transitions
> already equal what would be generated by the proposed change.  For
> example, for America/Manuas the 1963 transition is currently this:
> 
> Mon Dec  9 03:59:59 1963 UTC = Sun Dec  8 23:59:59 1963 AMT isdst=0
> Mon Dec  9 04:00:00 1963 UTC = Mon Dec  9 01:00:00 1963 AMST isdst=1
> 
> and this transition isn't affected by the proposed change.  So I don't
> see the need for this part of the change.

You are right. I just used zdump for final check of my review and I was 
still grasping the tz data format.

Just checking: the only real difference between the present data and my 
proposed patch in this matter would be the creation of a new timezone 
(America/Brasilia). As this new timezone is only necessary to reflect a 
time difference between America/Sao_Paulo and America/Brasilia BEFORE 
1970 it shall not be created.

>>2. The starting time of DST for 1966 was wrong as the 57843 decree 
>>stablishes that DST shall [end] at 1966-03-01 01:00 and on 1st of March 
>>00:00 from 1967 and on.
> 
> 
> I'm inclined to think that this may be a typographical error or
> ambiguity in decree 57,843 <http://pcdsh01.on.br/HV57843.htm>.  It'd
> be unusual for Brazil to change at any time other than midnight.  This
> reminds me of the 24-hour error in Decree 4,844 this year (though the
> latter error was corrected after a couple of days).  However, I don't
> read Portuguese so I'm not really qualified to interpret any wording
> problems in decree 57,843.

I would not call this error typographical, but probably something worst: 
the guy that originally wrote the decree had this fancy idea of ending 
DST time in a "better" hour or something like that.

Anyway I agree that the brazilian tradition of time changes at zero hour 
and the tiny impact this change would cause calls for something simple 
as the comment you proposed below, not a new rule as I proposed.

>>5. America/Sao_Paulo zone had a DST during the whole 1964. I can't see 
>>where it came from. There is no decree mentioning it.
> 
> It's not all of 1964, it's only the period from 1963-10-23 00:00 to
> 1964-03-01 00:00.  I think issue (5) is the same as issue (1) above.
> It's merely a different way to split the work between the Zone and the
> Rule lines; the actual transitions are the same regardless of whether
> the proposed patch is applied.

Yeah, I understand that now.

> Here's a diff to reflect the above comments.  I'll include something
> like this in my next proposed patch.

I believe your patch is fine (much better than mine BTW).


Rodrigo Severo