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Bug #51975 Missing DST free (UTC±X) timezones in DateTimeZone::listIdentifiers()
Submitted: 2010-06-02 15:27 UTC Modified: 2010-06-02 19:23 UTC
From: V-o-E at gmx dot de Assigned:
Status: Not a bug Package: Date/time related
PHP Version: 5.3.2 OS: All
Private report: No CVE-ID: None
View Add Comment Developer Edit
 [2010-06-02 15:27 UTC] V-o-E at gmx dot de 
Description:
------------
There are not daylight saving time free timezones (UTC±X) in DateTimeZone::listIdentifiers() (same with DateTimeZone::ALL) except UTC±0.

As workaround i can use buggy "Etc/GMT±X" from DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC):

Etc/GMT+2 => Etc/GMT-2
Etc/GMT-2 => Etc/GMT+2

See: http://en.wikipedia.org/wiki/List_of_time_zones_by_UTC_offset


Test script:
---------------
var_dump(DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC));

var_dump(DateTimeZone::listIdentifiers());

$a = DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC);
var_dump($a[373]); // output: string(9) "Etc/GMT+2"

$b = DateTimeZone::listIdentifiers();
var_dump($b[373]); // output: string(15) "Pacific/Fakaofo"

date_default_timezone_set('UTC');
echo date('H:i:s') . "\n"; // output: 13:13:01

date_default_timezone_set('Etc/GMT+2');
echo date('H:i:s') . "\n"; // output: 11:13:01

date_default_timezone_set('Etc/GMT-2');
echo date('H:i:s') . "\n"; // output: 15:13:01

date_default_timezone_set('Pacific/Fakaofo');
echo date('H:i:s') . "\n"; // output: 01:13:01

Expected result:
----------------
array(564) {
...
}
array(xyz) {
...
  [405]=>
  string(3) "UTC"
  [406]=>
  string(3) "UTC-12"
  [407]=>
  string(3) "UTC-11"
...
}
string(9) "Pacific/Fakaofo"
string(15) "Pacific/Fakaofo"
13:16:08
15:16:08
11:16:08
03:16:08

Actual result:
--------------
array(564) {
...
}
array(406) {
...
  [405]=>
  string(3) "UTC"
}
string(9) "Etc/GMT+2"
string(15) "Pacific/Fakaofo"
13:16:08
11:16:08
15:16:08
03:16:08

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 [2010-06-02 15:41 UTC] aharvey@php.net
-Status: Open +Status: Bogus
 [2010-06-02 15:41 UTC] aharvey@php.net 
The Olson tz database -- which forms the basis of the time zone support both for PHP and pretty much every operating system not called Windows -- doesn't define any time zones relative to UTC other than the Etc/GMT±x time zones and the UTC time zone itself.

The Etc/GMT time zones are the "wrong way around", but that's been the case for decades, and isn't something we (or probably anyone else) can fix without confusing people even more.
 [2010-06-02 19:23 UTC] V-o-E at gmx dot de 
oh, i see.

# We use POSIX-style signs in the Zone names and the output abbreviations,
# even though this is the opposite of what many people expect.
# POSIX has positive signs west of Greenwich, but many people expect
# positive signs east of Greenwich.  For example, TZ='Etc/GMT+4' uses
# the abbreviation "GMT+4" and corresponds to 4 hours behind UTC
# (i.e. west of Greenwich) even though many people would expect it to
# mean 4 hours ahead of UTC (i.e. east of Greenwich).
#
# In the draft 5 of POSIX 1003.1-200x, the angle bracket notation
# (which is not yet supported by the tz code) allows for
# TZ='<GMT-4>+4'; if you want time zone abbreviations conforming to
# ISO 8601 you can use TZ='<-0400>+4'.  Thus the commonly-expected
# offset is kept within the angle bracket (and is used for display)
# while the POSIX sign is kept outside the angle bracket (and is used
# for calculation).
#
# Do not use a TZ setting like TZ='GMT+4', which is four hours behind
# GMT but uses the completely misleading abbreviation "GMT".

# Earlier incarnations of this package were not POSIX-compliant,
# and had lines such as
#		Zone	GMT-12		-12	-	GMT-1200
# We did not want things to change quietly if someone accustomed to the old
# way does a
#		zic -l GMT-12
# so we moved the names into the Etc subdirectory.

Zone	Etc/GMT-14	14	-	GMT-14	# 14 hours ahead of GMT
Zone	Etc/GMT-13	13	-	GMT-13
Zone	Etc/GMT-12	12	-	GMT-12
Zone	Etc/GMT-11	11	-	GMT-11
Zone	Etc/GMT-10	10	-	GMT-10
Zone	Etc/GMT-9	9	-	GMT-9
Zone	Etc/GMT-8	8	-	GMT-8
Zone	Etc/GMT-7	7	-	GMT-7
Zone	Etc/GMT-6	6	-	GMT-6
Zone	Etc/GMT-5	5	-	GMT-5
Zone	Etc/GMT-4	4	-	GMT-4
Zone	Etc/GMT-3	3	-	GMT-3
Zone	Etc/GMT-2	2	-	GMT-2
Zone	Etc/GMT-1	1	-	GMT-1
Zone	Etc/GMT+1	-1	-	GMT+1
Zone	Etc/GMT+2	-2	-	GMT+2
Zone	Etc/GMT+3	-3	-	GMT+3
Zone	Etc/GMT+4	-4	-	GMT+4
Zone	Etc/GMT+5	-5	-	GMT+5
Zone	Etc/GMT+6	-6	-	GMT+6
Zone	Etc/GMT+7	-7	-	GMT+7
Zone	Etc/GMT+8	-8	-	GMT+8
Zone	Etc/GMT+9	-9	-	GMT+9
Zone	Etc/GMT+10	-10	-	GMT+10
Zone	Etc/GMT+11	-11	-	GMT+11
Zone	Etc/GMT+12	-12	-	GMT+12

This is output of "etcetera" file from "Olson tz database".
It is not deprecated, isn't it?

This are the "Etc*" zones from "backward" file:
Link	Etc/GMT			GMT+0
Link	Etc/GMT			GMT-0
Link	Etc/GMT			GMT0
Link	Etc/GMT			Greenwich
Link	Etc/UCT			UCT
Link	Etc/UTC			UTC
Link	Etc/UTC			Universal
Link	Etc/UTC			Zulu

So i think the "Etc/GMT±x" timezones from "etcetera" should be in output of:
DateTimeZone::listIdentifiers()
DateTimeZone::listIdentifiers(DateTimeZone::ALL)
DateTimeZone::listIdentifiers(DateTimeZone::UTC)

and not only in:
DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC)

what is your opinion?
 
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