Subject: bug#10413: closed (Re: bug#10413: Invalid date result in specific date operations)

From: [email-masked] (GNU bug Tracking System)
Date: Sat, 31 Dec 2011 22:44:02 +0000

Your bug report

#10413: Invalid date result in specific date operations

which was filed against the coreutils package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to [email-masked].

-- 
10413: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10413
GNU Bug Tracking System
Contact [email-masked] with problems

Subject: Re: bug#10413: Invalid date result in specific date operations
From: Eric Blake <[email-masked]>
To: Vicente Pérez M <[email-masked]>
Cc: [email-masked]
Date: Sat, 31 Dec 2011 15:39:58 -0700
List-Id: <debbugs-submit.debbugs.gnu.org>

tag 10413 notabug
thanks

On 12/29/2011 11:02 AM, Vicente Pérez M wrote:
> How to repeat:
> 
> 
> date -d '2011-08-21 + 1 DAY' +%Y-%m-%d
> date -d '2010-10-10 + 1 DAY' +%Y-%m-%d
> 
> These dates is just when change from normal time UTC-4 to dts UCT-3
> 
> result: invalid date
> 
> The same operation with --utc works fine.
> date -d '2011-08-21 + 1 DAY' +%Y-%m-%d --utc
> date -d '2010-10-10 + 1 DAY' +%Y-%m-%d --utc

Thanks for the report.  You failed to mention your exact TZ settings,
although you hinted at it via 'dts UTC-3', but the behavior you observed
is by design and not a bug.  In particular time zones, attempts to land
in a time that falls during the skipped hour are rejected, and using UTC
(which has no daylight savings) is a correct way to avoid the issue.
Another way is to pinpoint times to noon rather than the default of
midnight (no known time zone has a daylight savings transition at noon),
since your particular time zone appears to be among those zones where
the daylight savings rules kick in at midnight:

date -d '2011-08-21 12:00pm + 1 day' +%Y-%m-%d

More on this topic can be found in the FAQ:
https://www.gnu.org/software/coreutils/faq/#The-date-command-is-not-working-right_002e

-- 
Eric Blake   [email-masked]    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

Subject: Invalid date result in specific date operations
From: Vicente Pérez M <[email-masked]>
To: [email-masked]
Date: Thu, 29 Dec 2011 15:02:46 -0300
List-Id: <debbugs-submit.debbugs.gnu.org>

How to repeat:

date -d '2011-08-21 + 1 DAY' +%Y-%m-%d
date -d '2010-10-10 + 1 DAY' +%Y-%m-%d

These dates is just when change from normal time UTC-4 to dts UCT-3

result: invalid date

The same operation with --utc works fine.
date -d '2011-08-21 + 1 DAY' +%Y-%m-%d --utc
date -d '2010-10-10 + 1 DAY' +%Y-%m-%d --utc