[tz] Another change on Brazilian DST time

[Paul Eggert]

On 10/4/18 4:49 AM, Fábio Gomes wrote:
>   How long does it takes to update tzdata with this new information?


It depends on what you consider an "update". I just now updated the 
development version <https://github.com/eggert/tz> with the attached 
patch, and you can use that now if you like. I'd like to plan for a new 
tzdb release soon after the presidential decree is published (please let 
me know when that happens).


> we have a very shourt window to apply this new update.


That's unfortunately true. We have a paragraph about this in 
<https://data.iana.org/time-zones/tz-link.html>. Here's how Google 
Translate renders it in Portuguese, and perhaps you can improve this 
translation and send it to Moreira Franco, the minister of Mines and 
Energy, who's supposed to be in charge of DST in Brazil:


---


Se o seu governo planeja alterar seus limites de fuso horário ou as 
regras de horário de verão, informe <tz at iana.org> com bastante 
antecedência, pois isso coordenará as atualizações para muitos telefones 
celulares, computadores e outros dispositivos em todo o mundo. Com menos 
de um ano de antecedência, há uma boa chance de que alguns relógios 
baseados em computador operem incorretamente após a alteração, devido a 
atrasos na propagação de atualizações de software e dados. Quanto mais 
curto for o aviso, mais prováveis serão os problemas do relógio; veja 
"Sobre o tempo das mudanças de fuso horário" 
<https://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-changes/> 
para exemplos.

-------------- next part --------------
From efda0562d7fc7bc90b6cab76998fab8b4953e056 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert at cs.ucla.edu>
Date: Thu, 4 Oct 2018 08:24:15 -0700
Subject: [PROPOSED] Southern Brazil starts DST two weeks later in 2018

* NEWS: Mention this.
* southamerica (Brazil): New rule just for spring 2018.
---
 NEWS         | 5 +++++
 southamerica | 9 ++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index e217a50..395d9a8 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,7 @@ Unreleased, experimental changes
 
   Briefly:
   Volgograd moves from +03 to +04 on 2018-10-28.
+  Southern Brazil starts DST 2018-11-18, not 2018-11-04.
   Fiji ends DST 2019-01-13, not 2019-01-20.
   Most of Chile changes DST dates, effective 2019-04-06.
 
@@ -12,6 +13,10 @@ Unreleased, experimental changes
     Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
     (Thanks to Alexander Fetisov and Stepan Golosunov.)
 
+    Southern Brazil starts DST 2018-11-18 instead of the 2018-11-04
+    previously predicted.  (Thanks to Fábio Gomes.)  Guess that this
+    is a one-time change.
+
     Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
     predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
     accordingly.
diff --git a/southamerica b/southamerica
index dedfb28..214316e 100644
--- a/southamerica
+++ b/southamerica
@@ -927,7 +927,14 @@ Rule	Brazil	2016	2022	-	Feb	Sun>=15	0:00	0	-
 # ... https://www.timeanddate.com/news/time/brazil-delays-dst-2018.html
 # From Steffen Thorsen (2017-12-20):
 # http://www.planalto.gov.br/ccivil_03/_ato2015-2018/2017/decreto/D9242.htm
-Rule	Brazil	2018	max	-	Nov	Sun>=1	0:00	1:00	-
+# From Fábio Gomes (2018-10-04):
+# The Brazilian president just announced a new change on this year DST.
+# It was scheduled to start on November 4th and it was changed to November 18th.
+# From Paul Eggert (2018-10-04):
+# This attempts to avoid confusion during the November 4 and 11 national high
+# school exams, which were mis-scheduled.  Guess that it's just this year.
+Rule	Brazil	2018	only	-	Nov	Sun>=15	0:00	1:00	-
+Rule	Brazil	2019	max	-	Nov	Sun>=1	0:00	1:00	-
 Rule	Brazil	2023	only	-	Feb	Sun>=22	0:00	0	-
 Rule	Brazil	2024	2025	-	Feb	Sun>=15	0:00	0	-
 Rule	Brazil	2026	only	-	Feb	Sun>=22	0:00	0	-
-- 
2.17.1