[Bug 1452314] [NEW] TZ=EDT date reporting misleading times

[Dan McGrath]

Public bug reported:

While working in a UTC system I stumbled upon some oddities with the
date command, that at least appear to differ from how BSD systems report
(correctly) when EDT or gibberish is passed to date via the TZ env
variable.

Currently I am in EST timezone, which during daylight savings time, is
EDT. If I run date with "TZ=", I get changes in timezones used by date
as expected, but noticed that EDT was actually returning UTC time, but
displays "EDT" (so 10am becomes 2pm) despite actually displaying UTC.

As a test, I also tried supply a bunch of gibberish only to find that
BSD actually replaces the gibberish with the text "UTC", while linux
systems just spit back the same gibberish (ie: TZ=jhsdjflhljak date),
but report it in UTC time. So in the case where a user supplies a valid
timezone such as EDT, one can make time related mistakes as linux will
actually report UTC but use the label the user supplied. What is worse,
is that Ubuntu actually shows my current time zone as "EDT" yet it isn't
recognized as a valid zone!

Here are some same outputs to clarify the problem on linux and bsd:

Freebsd:
[dan at barley ~]$ TZ=UTC date 
Wed May  6 15:09:26 UTC 2015
[dan at barley ~]$ TZ=EST date
Wed May  6 10:09:32 EST 2015
[dan at barley ~]$ TZ=EDT date
Wed May  6 15:09:39 UTC 2015
[dan at barley ~]$ TZ=lkjhsd date
Wed May  6 15:11:16 UTC 2015   <==== good, correctly informs me what its reporting


Ubuntu 14.04:
dan at wks:~$ TZ=UTC date
Wed May  6 15:10:48 UTC 2015
dan at wks:~$ TZ=EST date
Wed May  6 10:10:48 EST 2015
dan at wks:~$ TZ=EDT date
Wed May  6 15:10:48 EDT 2015   <==== EDT = UTC?!
dan at wks:~$ date
Wed May  6 11:10:56 EDT 2015   <==== the real EDT time
dan at wks:~$ TZ=lkjhsd date
Wed May  6 15:11:30 lkjhsd 2015  <===== wth?

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: coreutils 8.21-1ubuntu5.1
ProcVersionSignature: Ubuntu 3.13.0-46.79-generic 3.13.11-ckt15
Uname: Linux 3.13.0-46-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.10
Architecture: amd64
CurrentDesktop: XFCE
Date: Wed May  6 11:01:37 2015
InstallationDate: Installed on 2014-06-11 (329 days ago)
InstallationMedia: Xubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
SourcePackage: coreutils
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: coreutils (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug trusty

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https://bugs.launchpad.net/bugs/1452314

Title:
  TZ=EDT date reporting misleading times

Status in coreutils package in Ubuntu:
  New

Bug description:
  While working in a UTC system I stumbled upon some oddities with the
  date command, that at least appear to differ from how BSD systems
  report (correctly) when EDT or gibberish is passed to date via the TZ
  env variable.

  Currently I am in EST timezone, which during daylight savings time, is
  EDT. If I run date with "TZ=", I get changes in timezones used by date
  as expected, but noticed that EDT was actually returning UTC time, but
  displays "EDT" (so 10am becomes 2pm) despite actually displaying UTC.

  As a test, I also tried supply a bunch of gibberish only to find that
  BSD actually replaces the gibberish with the text "UTC", while linux
  systems just spit back the same gibberish (ie: TZ=jhsdjflhljak date),
  but report it in UTC time. So in the case where a user supplies a
  valid timezone such as EDT, one can make time related mistakes as
  linux will actually report UTC but use the label the user supplied.
  What is worse, is that Ubuntu actually shows my current time zone as
  "EDT" yet it isn't recognized as a valid zone!

  Here are some same outputs to clarify the problem on linux and bsd:

  Freebsd:
  [dan at barley ~]$ TZ=UTC date 
  Wed May  6 15:09:26 UTC 2015
  [dan at barley ~]$ TZ=EST date
  Wed May  6 10:09:32 EST 2015
  [dan at barley ~]$ TZ=EDT date
  Wed May  6 15:09:39 UTC 2015
  [dan at barley ~]$ TZ=lkjhsd date
  Wed May  6 15:11:16 UTC 2015   <==== good, correctly informs me what its reporting

  
  Ubuntu 14.04:
  dan at wks:~$ TZ=UTC date
  Wed May  6 15:10:48 UTC 2015
  dan at wks:~$ TZ=EST date
  Wed May  6 10:10:48 EST 2015
  dan at wks:~$ TZ=EDT date
  Wed May  6 15:10:48 EDT 2015   <==== EDT = UTC?!
  dan at wks:~$ date
  Wed May  6 11:10:56 EDT 2015   <==== the real EDT time
  dan at wks:~$ TZ=lkjhsd date
  Wed May  6 15:11:30 lkjhsd 2015  <===== wth?

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: coreutils 8.21-1ubuntu5.1
  ProcVersionSignature: Ubuntu 3.13.0-46.79-generic 3.13.11-ckt15
  Uname: Linux 3.13.0-46-generic x86_64
  NonfreeKernelModules: nvidia
  ApportVersion: 2.14.1-0ubuntu3.10
  Architecture: amd64
  CurrentDesktop: XFCE
  Date: Wed May  6 11:01:37 2015
  InstallationDate: Installed on 2014-06-11 (329 days ago)
  InstallationMedia: Xubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
  SourcePackage: coreutils
  UpgradeStatus: No upgrade log present (probably fresh install)

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