[Bug 1920987] Re: Europe/Simferopol, Crimea is RUSSIA

Wed Mar 24 10:48:20 UTC 2021

The upstream IANA tzdata file format is very restrictive and cannot
change and reflect country codes correctly, across correct historical
dates.

>From "europe" file:
Zone Europe/Simferopol	 2:16:24 -	LMT	1880
			 2:16	-	SMT	1924 May  2 # Simferopol Mean T
			 2:00	-	EET	1930 Jun 21
			 3:00	-	MSK	1941 Nov
			 1:00	C-Eur	CE%sT	1944 Apr 13
			 3:00	Russia	MSK/MSD	1990
			 3:00	-	MSK	1990 Jul  1  2:00
			 2:00	-	EET	1992
# Central Crimea used Moscow time 1994/1997.
#
# From Paul Eggert (2006-03-22):
# The _Economist_ (1994-05-28, p 45) reports that central Crimea switched
# from Kiev to Moscow time sometime after the January 1994 elections.
# Shanks (1999) says "date of change uncertain", but implies that it happened
# sometime between the 1994 DST switches.  Shanks & Pottenger simply say
# 1994-09-25 03:00, but that can't be right.  For now, guess it
# changed in May.
			 2:00	E-Eur	EE%sT	1994 May
# From IATA SSIM (1994/1997), which also says that Kerch is still like Kiev.
			 3:00	E-Eur	MSK/MSD	1996 Mar 31  0:00s
			 3:00	1:00	MSD	1996 Oct 27  3:00s
# IATA SSIM (1997-09) says Crimea switched to EET/EEST.
# Assume it happened in March by not changing the clocks.
			 3:00	Russia	MSK/MSD	1997
			 3:00	-	MSK	1997 Mar lastSun  1:00u
# From Alexander Krivenyshev (2014-03-17):
# time change at 2:00 (2am) on March 30, 2014
# https://vz.ru/news/2014/3/17/677464.html
# From Paul Eggert (2014-03-30):
# Simferopol and Sevastopol reportedly changed their central town clocks
# late the previous day, but this appears to have been ceremonial
# and the discrepancies are small enough to not worry about.
			 2:00	EU	EE%sT	2014 Mar 30  2:00
			 4:00	-	MSK	2014 Oct 26  2:00s
			 3:00	-	MSK

The above defines which timezone was used when in Crimea.

But the mapping from Europe/Simferopol => country code [UA,RU] as appropriate for a given time period is not possible in the zone.tab file. Hence it currently stayed with:
./zone.tab:UA	+4457+03406	Europe/Simferopol	Crimea

There is a newer format in zone1970.tab file which says:
./zone1970.tab:RU,UA	+4457+03406	Europe/Simferopol	Crimea

But that is not helpful, as it lists two countries. And it still doesn't
map country codes to the correct time periods.

It almost feels like we either need a new country code for Crimea to
explain that depending which year one is in, it should be one or the
other country code. Or we need to extend the zore1970.tab format similar
to the file format of europe format such that country codes can be
specified for every relevant time period.

So to get where you want to be, IANA needs to create a new tzdata format
and for everyone to switch to it. I guess that would need to be
requested via Discussions mailing list at IANA - see
https://www.iana.org/time-zones

There is nothing in particular that Ubuntu can do to fix tzdata. As
disagreement across other users of tzdata across the network can
introduce interoperability bugs.

My only recommendation is to use Europe/Kiev or Europe/Moscow zones,
which have the correct country code mappings for the most recent
decades.

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https://bugs.launchpad.net/bugs/1920987

Title:
  IANA tzdata file format cannot represent different country code for a
  given timezone in different time periods [ i.e. Europe/Simferopol
  country code changes ]

Status in tzdata package in Ubuntu:
  Opinion

Bug description:
  Europe/Simferopol,      Crimea is RUSSIA

  ProblemType: Bug
  DistroRelease: Ubuntu 21.04
  Package: tzdata 2021a-1ubuntu1
  ProcVersionSignature: Ubuntu 5.11.0-11.12-generic 5.11.0
  Uname: Linux 5.11.0-11-generic x86_64
  ApportVersion: 2.20.11-0ubuntu60
  Architecture: amd64
  CurrentDesktop: MATE
  Date: Tue Mar 23 21:44:56 2021
  InstallationDate: Installed on 2021-03-21 (1 days ago)
  InstallationMedia: Ubuntu-MATE 21.04 "Hirsute Hippo" - Alpha amd64 (20210321)
  PackageArchitecture: all
  SourcePackage: tzdata
  UpgradeStatus: No upgrade log present (probably fresh install)

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