From: Benjamin Drung <benjamin.drung@canonical.com>
Date: Mon, 20 Mar 2023 17:49:11 +0100
Subject: Dynamically determine list of available and common timezones

The Debian/Ubuntu packages of pytz include a patch to not install pytz's
zoneinfo database and instead load data from the system zoneinfo
database. This keeps pytz up to date when system timezone updates are
installed which is generally a good idea.

The `pytz/__init__.py` includes `common_timezones` and `all_timezones`
lists, which enumerate the time zones in the database pytz was released
with. If pytz is instead using the system database, these lists may not
be correct (e.g. missing newly added time zones).

Dynamically determine `all_timezones` and `common_timezones`. For
`all_timezones` use `zoneinfo` from Python 3.9 and for
`common_timezones` parse `/usr/share/zoneinfo/zone1970.tab`.

Bug: https://launchpad.net/bugs/207604
Forwarded: not-needed
Signed-off-by: Benjamin Drung <benjamin.drung@canonical.com>
---
 pytz/__init__.py | 941 ++-----------------------------------------------------
 1 file changed, 21 insertions(+), 920 deletions(-)

Index: python-tz-2025.2/src/pytz/__init__.py
===================================================================
--- python-tz-2025.2.orig/src/pytz/__init__.py
+++ python-tz-2025.2/src/pytz/__init__.py
@@ -522,6 +522,134 @@ def _read_timezones_from_zone_tab() -> s
         timezones.add(line.split("\t")[2])
     return timezones
 
+_extra_common_timezones_set = {
+ 'Africa/Accra',
+ 'Africa/Addis_Ababa',
+ 'Africa/Asmara',
+ 'Africa/Bamako',
+ 'Africa/Bangui',
+ 'Africa/Banjul',
+ 'Africa/Blantyre',
+ 'Africa/Brazzaville',
+ 'Africa/Bujumbura',
+ 'Africa/Conakry',
+ 'Africa/Dakar',
+ 'Africa/Dar_es_Salaam',
+ 'Africa/Djibouti',
+ 'Africa/Douala',
+ 'Africa/Freetown',
+ 'Africa/Gaborone',
+ 'Africa/Harare',
+ 'Africa/Kampala',
+ 'Africa/Kigali',
+ 'Africa/Kinshasa',
+ 'Africa/Libreville',
+ 'Africa/Lome',
+ 'Africa/Luanda',
+ 'Africa/Lubumbashi',
+ 'Africa/Lusaka',
+ 'Africa/Malabo',
+ 'Africa/Maseru',
+ 'Africa/Mbabane',
+ 'Africa/Mogadishu',
+ 'Africa/Niamey',
+ 'Africa/Nouakchott',
+ 'Africa/Ouagadougou',
+ 'Africa/Porto-Novo',
+ 'America/Anguilla',
+ 'America/Antigua',
+ 'America/Aruba',
+ 'America/Atikokan',
+ 'America/Blanc-Sablon',
+ 'America/Cayman',
+ 'America/Creston',
+ 'America/Curacao',
+ 'America/Dominica',
+ 'America/Grenada',
+ 'America/Guadeloupe',
+ 'America/Kralendijk',
+ 'America/Lower_Princes',
+ 'America/Marigot',
+ 'America/Montserrat',
+ 'America/Nassau',
+ 'America/Port_of_Spain',
+ 'America/St_Barthelemy',
+ 'America/St_Kitts',
+ 'America/St_Lucia',
+ 'America/St_Thomas',
+ 'America/St_Vincent',
+ 'America/Tortola',
+ 'Antarctica/DumontDUrville',
+ 'Antarctica/McMurdo',
+ 'Antarctica/Syowa',
+ 'Antarctica/Vostok',
+ 'Arctic/Longyearbyen',
+ 'Asia/Aden',
+ 'Asia/Bahrain',
+ 'Asia/Kuala_Lumpur',
+ 'Asia/Kuwait',
+ 'Asia/Muscat',
+ 'Asia/Phnom_Penh',
+ 'Asia/Vientiane',
+ 'Atlantic/Reykjavik',
+ 'Atlantic/St_Helena',
+ 'Canada/Atlantic',
+ 'Canada/Central',
+ 'Canada/Eastern',
+ 'Canada/Mountain',
+ 'Canada/Newfoundland',
+'Canada/Pacific',
+ 'Europe/Amsterdam',
+ 'Europe/Bratislava',
+ 'Europe/Busingen',
+ 'Europe/Copenhagen',
+ 'Europe/Guernsey',
+ 'Europe/Isle_of_Man',
+ 'Europe/Jersey',
+ 'Europe/Ljubljana',
+ 'Europe/Luxembourg',
+ 'Europe/Mariehamn',
+ 'Europe/Monaco',
+ 'Europe/Oslo',
+ 'Europe/Podgorica',
+ 'Europe/San_Marino',
+ 'Europe/Sarajevo',
+ 'Europe/Skopje',
+ 'Europe/Stockholm',
+ 'Europe/Vaduz',
+ 'Europe/Vatican',
+ 'Europe/Zagreb',
+ 'GMT',
+ 'Indian/Antananarivo',
+ 'Indian/Christmas',
+ 'Indian/Cocos',
+ 'Indian/Comoro',
+ 'Indian/Kerguelen',
+ 'Indian/Mahe',
+ 'Indian/Mayotte',
+ 'Indian/Reunion',
+ 'Pacific/Chuuk',
+ 'Pacific/Funafuti',
+ 'Pacific/Majuro',
+ 'Pacific/Midway',
+ 'Pacific/Pohnpei',
+ 'Pacific/Saipan',
+ 'Pacific/Wake',
+ 'Pacific/Wallis',
+ 'US/Alaska',
+ 'US/Arizona',
+ 'US/Central',
+ 'US/Eastern',
+ 'US/Hawaii',
+ 'US/Mountain',
+ 'US/Pacific',
+ 'UTC'}
+
+all_timezones_set = zoneinfo.available_timezones() - {"Factory", "localtime"}
+common_timezones_set = (_read_timezones_from_zone_tab() | _extra_common_timezones_set) & all_timezones_set
+
+all_timezones = sorted(all_timezones_set)
+common_timezones = sorted(common_timezones_set)
 
 if __name__ == '__main__':
     _test()