1107837 - Incorrect offset change in 2015

Status: RESOLVED DUPLICATE of bug 1346211

(Core :: JavaScript Engine, defect)

Description

[Dmitry Krokhin]

User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.124 YaBrowser/14.10.2062.12521 Safari/537.36

Steps to reproduce:

My application works with dates and it fails when working with dates in January 2015.

Open console on any site and run this command:
for(n of [4,5,6,7,8,9]) console.log(new Date(2015,0, n) + ' : ' + new Date(2015,0, n).getTimezoneOffset());


Actual results:

The result is: 
"Sun Jan 04 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Mon Jan 05 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Tue Jan 06 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Tue Jan 06 2015 23:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Thu Jan 08 2015 00:00:00 GMT+0400 (Russia TZ 2 Daylight Time) : -240"
"Fri Jan 09 2015 00:00:00 GMT+0400 (Russia TZ 2 Daylight Time) : -240"

The application works as there would be switching time from standart to daylight.
But it is incorrect, we don't have this change.


Expected results:

The result should be:

"Sun Jan 04 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Mon Jan 05 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Tue Jan 06 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Tue Jan 07 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"
"Thu Jan 08 2015 00:00:00 GMT+0400 (Russia TZ 2 Standard Time) : -180"
"Fri Jan 09 2015 00:00:00 GMT+0300 (Russia TZ 2 Standard Time) : -180"

Nothing should be changed on in this period (and in the future).

Comment 1

[Dmitry Krokhin]

There should be no upcoming Daylight Saving Time changes from now.

Comment 2

[Boris Zbarsky [:bzbarsky]]

This may be related to bug 1106530.  It sure sounds like something weird is gong on with this timezone in the timezone database...

Comment 3

[Dmitry Krokhin]

(In reply to Boris Zbarsky [:bz] from comment #2)
> This may be related to bug 1106530.  It sure sounds like something weird is
> gong on with this timezone in the timezone database...

You are right - very similar problem with the same timezone.
Maybe this bug is not hard to fix? As i understand, there is a record about switching from standard time to daylight in the timezone database. The timezone database is hardcoded in the source? Or maybe there is a way to change this database from extension? 

Please help, this is very important application for us and there is no way to change the browser until January 2015 (a lot of users on the intranet use only firefox).

Firefox is opensource, but i can't find a way to try creating hotfix myself. 
Maybe you can help with this? This is another way how i can try to fix it.

Comment 4

[Dmitry Krokhin]

I checkup http://www.iana.org/time-zones, looks like it contains all changes and is actual.

Comment 5

[Dmitry Krokhin]

(In reply to Dmitry Krokhin from comment #4)
> I checkup http://www.iana.org/time-zones, looks like it contains all changes
> and is actual.

The result of analyze this database is this items:

# From Alexander Krivenyshev (2014-07-01): According to the Russian news (ITAR-TASS News Agency)
# the State Duma has approved ... the draft bill on returning to winter time standard and return Russia 11 time zones. The new regulations will come into effect on October 26, 2014 at 02:00 ...
http://www.worldtimezone.com/dst_news/dst_news_russia65.html

Please, note this important row:
1. Moscow time as UTC+3. No seasonal clock change (Daylight Saving Time is abolished).

Later this law was signed:
# From Alexander Krivenyshev (2014-07-22): Putin signed the Federal Law 431985-6 ... (in Russian)

And now we should not have time switching in the future.

Comment 7

[:Gijs (out for now; he/him)]

Hm, this seems subtly different, though. Marking see also instead, although I'd be surprised if it wasn't fixable by the switch to alternative windows APIs like bug 1079720.

Comment 8

[André Bargull [:anba]]

Dup'ing forward to bug 1346211 which should have fixed this problem. Please reopen if the issue is still present. Thanks!