at command ignores savings time when given UTC time

[Paolo Montrasio]

at doesn't handle correctly UTC date. My timezone is CEST which is UTC+1 plus one more hour for daylight saving. That make is two hours more than UTC. This is what happens when I try to run an at task specifying the date as UTC.

$ date
Sun Sep 20 17:07:42 CEST 2009
$ date -u
Sun Sep 20 15:07:44 UTC 2009
$ at 1510 UTC 20 SEP 2009
at: refusing to create job destined in the past

Actually 15:10 UTC is more than two minutes in the future.

$ at 1610 UTC 20 SEP 2009

works. I downloaded the source package with apt-get source at and found the bug in the parsetime.y file.
I checked this both on a 8.10 and on a 9.04 machine and got the same results.

I discovered that a bug for this has already been opened to Debian in 2006 for this very same version of the at package (3.1.10) and a patch has been submitted by Håkon Stordahl (I think he's a maintainer). I tried it and it works for me so I attach it to this message. Refer to http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=364975 for the details.
Unfortunately it seems that the patch didn't make it yet in any released package because a debian 5 server of mine has the same package version and the same bug. It could be possible to apply it to the next Ubuntu release?

Distribution and package info:

For Ubuntu 8.10

$ lsb_release -rd
Description: Ubuntu 8.10
Release: 8.10

$ apt-cache policy at
at:
  Installed: 3.1.10.1ubuntu3
  Candidate: 3.1.10.1ubuntu3
  Version table:
 *** 3.1.10.1ubuntu3 0
        500 http://it.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status

Despite package number 3.1.10 "at -V" reports "at version 3.1.9"

For Ubuntu 9.04

$ lsb_release -rd
Description: Ubuntu 8.10
Release: 8.10

$ apt-cache policy at
at:
  Installed: 3.1.10.2ubuntu2
  Candidate: 3.1.10.2ubuntu2
  Version table:
 *** 3.1.10.2ubuntu2 0
        500 http://it.archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/status

"at -V" also reports "at version 3.1.9" here.

[Paolo Montrasio (paolo-paolomontrasio)]

at still has the bug in Karmic.

$ date -u
Sat Mar 13 14:10:36 UTC 2010
$ at 1415 UTC 13 MAR 2010
at: refusing to create job destined in the past
$ apt-cache policy at
at:
  Installed: 3.1.11-1ubuntu4
  Candidate: 3.1.11-1ubuntu4
  Version table:
 *** 3.1.11-1ubuntu4 0
        500 http://mirror.switch.ch karmic/main Packages
        100 /var/lib/dpkg/status

I'll reapply the patch from Debian.

[Philippe Clérié (pclerie)]

Just filed 889665 describing the same bug on natty.

[Paolo Montrasio (paolo-paolomontrasio)]

Still there in 12.04

[Jon Gabrielson (a-jon-g)]

This bug is alot more serious (once a year) that you might guess as it also affects daylight savings time.
All "at now" and "at now + 1 minute", etc... commands stopped working for 1 hour last night:

root@pbx:~ $ date
Sun Nov 2 01:34:09 CST 2014
root@pbx:~ $ echo "ls" |at now
at: refusing to create job destined in the past
root@pbx:~ $ echo "ls" |at now + 1 minute
at: refusing to create job destined in the past
root@pbx:~ $ echo "ls" |at now + 10 minute
at: refusing to create job destined in the past
root@pbx:~ $ echo "ls" |at now + 30 minute
job 413 at 2014-11-02 02:04
root@pbx:~ $ date
Sun Nov 2 01:34:30 CST 2014
root@pbx:~ $

[linuxwrangler (scrawford-pinpointresearch)]

Yes. I reported that bug three and a half years ago:
https://bugs.launchpad.net/ubuntu/+source/at/+bug/727514

That issue was determined to have the same cause as this one so it was marked as a duplicate. For whatever reason, reliable job scheduling is not an assigned priority for the distribution maintainers as this report started a half-decade ago.