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Re: [tz] tzcode2021e: uninitialized variable in localtime.c
by Paul Eggert Oct. 27, 2021

Oct. 27, 2021

On 10/22/21 07:49, Christos Zoulas wrote: > My linter reports "prevcorr" is uninitialized in the if statement > below the comment that starts "To avoid other botches". Thanks for mentioning that. This prompted me to find an obscure bug in localtime that would cause it to access an uninitialized local variable (which is undefined behavior) in cases involving 32-bit time_t code reading malformed 64-bit data. I installed the attached patch to fix the bug, and I hope this also pacifies your linter.

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[PROPOSED] Be more generous when dealing with v1 data
by Paul Eggert Oct. 27, 2021

Oct. 27, 2021

* NEWS: Mention this. * localtime.c (tzloadbody): In version 2 and later files, do not attempt to validate the version 1 header and data block; instead, ignore them except for the purpose of skipping over them, as per a recommendation in RFC 8536 section 4. Also, when the TZif file is version 1 and we break out near the end of the loop, do so only after altering nread and memmoving any later data; this avoids having later code attempt to parse the version 1 header as if it were a TZ string. --- NEWS | 6 +++++ localtime.c | 71 +++++++++++++++++++++++++++++++---------------------- 2 files changed, 47 insertions(+), 30 deletions(-) diff --git a/NEWS b/NEWS index d4a9823..0f684f7 100644 --- a/NEWS +++ b/NEWS @@ -14,6 +14,12 @@ Unreleased, experimental changes Fix bug when 32-bit time_t code reads malformed 64-bit TZif data. (Problem reported by Christos Zoulas.) + When reading a version 2 or later TZif file, the TZif reader now + validates the version 1 header and data block only enough to skip + over them, as recommended by RFC 8536 section 4. Also, the TZif + reader no longer mistakenly attempts to parse a version 1 TZIf + file header as a TZ string. + Release 2021e - 2021-10-21 18:41:00 -0700 diff --git a/localtime.c b/localtime.c index 6d736b2..39ef6e3 100644 --- a/localtime.c +++ b/localtime.c @@ -434,35 +434,45 @@ tzloadbody(char const *name, struct state *sp, bool doextend, if (close(fid) < 0) return errno; for (stored = 4; stored <= 8; stored *= 2) { - int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt); - int_fast32_t ttisutcnt = detzcode(up->tzhead.tzh_ttisutcnt); - int_fast64_t prevtr = -1; - int_fast32_t prevcorr; - int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt); - int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt); - int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt); - int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt); - char const *p = up->buf + tzheadsize; - /* Although tzfile(5) currently requires typecnt to be nonzero, - support future formats that may allow zero typecnt - in files that have a TZ string and no transitions. */ - if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS - && 0 <= typecnt && typecnt < TZ_MAX_TYPES - && 0 <= timecnt && timecnt < TZ_MAX_TIMES - && 0 <= charcnt && charcnt < TZ_MAX_CHARS - && (ttisstdcnt == typecnt || ttisstdcnt == 0) - && (ttisutcnt == typecnt || ttisutcnt == 0))) - return EINVAL; - if (nread - < (tzheadsize /* struct tzhead */ - + timecnt * stored /* ats */ + char version = up->tzhead.tzh_version[0]; + bool skip_datablock = stored == 4 && version; + int_fast32_t datablock_size; + int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt); + int_fast32_t ttisutcnt = detzcode(up->tzhead.tzh_ttisutcnt); + int_fast64_t prevtr = -1; + int_fast32_t prevcorr; + int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt); + int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt); + int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt); + int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt); + char const *p = up->buf + tzheadsize; + /* Although tzfile(5) currently requires typecnt to be nonzero, + support future formats that may allow zero typecnt + in files that have a TZ string and no transitions. */ + if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS + && 0 <= typecnt && typecnt < TZ_MAX_TYPES + && 0 <= timecnt && timecnt < TZ_MAX_TIMES + && 0 <= charcnt && charcnt < TZ_MAX_CHARS + && 0 <= ttisstdcnt && ttisstdcnt < TZ_MAX_TYPES + && 0 <= ttisutcnt && ttisutcnt < TZ_MAX_TYPES)) + return EINVAL; + datablock_size + = (timecnt * stored /* ats */ + timecnt /* types */ + typecnt * 6 /* ttinfos */ + charcnt /* chars */ + leapcnt * (stored + 4) /* lsinfos */ + ttisstdcnt /* ttisstds */ - + ttisutcnt)) /* ttisuts */ + + ttisutcnt); /* ttisuts */ + if (nread < tzheadsize + datablock_size) + return EINVAL; + if (skip_datablock) + p += datablock_size; + else { + if (! ((ttisstdcnt == typecnt || ttisstdcnt == 0) + && (ttisutcnt == typecnt || ttisutcnt == 0))) return EINVAL; + sp->leapcnt = leapcnt; sp->timecnt = timecnt; sp->typecnt = typecnt; @@ -578,13 +588,14 @@ tzloadbody(char const *name, struct state *sp, bool doextend, ttisp->tt_ttisut = *p++; } } - /* - ** If this is an old file, we're done. - */ - if (up->tzhead.tzh_version[0] == '\0') - break; - nread -= p - up->buf; - memmove(up->buf, p, nread); + } + + nread -= p - up->buf; + memmove(up->buf, p, nread); + + /* If this is an old file, we're done. */ + if (!version) + break; } if (doextend && nread > 2 && up->buf[0] == '\n' && up->buf[nread - 1] == '\n' && -- 2.31.1

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Extra transition type is generated by zic with -r specified
by Almaz Mingaleev Oct. 26, 2021

Oct. 26, 2021

I’ve tried to generate a TZif file with transitions up to 1 Jan 2100 using zic with -r and “-b fat”. However, an extra transition type is generated for many (all?) time zones. That type’s UTC offset is zero and it is used only for the last transition in the 64-bit section. What I did: mkdir /tmp/zic cd /tmp/zic git clone https://github.com/eggert/tz.git . make -C . zic make -C . NDATA= rearguard.zi mkdir data ./zic -b fat -r /@4102444800 -d ./data rearguard.zi Below is an investigation for Australia/Lord_Howe (I don’t think choice matters here). I couldn’t find a way to force zdump to print transitions for a given TZif file. Instead, please see human-readable dumps from the TZif from our internal tools immediately below and raw byte information at the bottom if you’d prefer to work with that. These are local time transition types for Australia/Lord_Howe: Types gmtOffset (seconds),isDst,ttisgmt,ttisstd,[gmtOffset ISO],[DST?] 38180,0,,,PT10H36M20S,STD 0,0,,,PT0S,STD <- this is odd 36000,0,,,PT10H,STD 41400,1,,,PT11H30M,DST 37800,0,,,PT10H30M,STD 39600,1,,,PT11H,DST Transitions: transition,type,[UTC time],[Type offset],[Type isDST] … 4063275000,5,2098-10-04T15:30:00Z,PT11H,DST 4078998000,4,2099-04-04T15:00:00Z,PT10H30M,STD 4094724600,5,2099-10-03T15:30:00Z,PT11H,DST 4102444800,1,2100-01-01T00:00:00Z,PT0S,STD <- this is odd So, after the upper bound specified in -r, the transitions say that GMT is used. As I’d expect, the 32-bit transitions are not affected when the upper bound in -r is after 2038. However, with -r /@1634833073 the 32-bit section also has 6 transition types and the last transition sets offset to 0. Is that a bug or is there a reason for such behaviour? Thanks, Almaz Byte manipulations: typecnt is 5 in 32-bit section: xxd -seek 36(4+1+15+4*4) -len 4 data/Australia/Lord_Howe 64-bit section starts at offset 674. timecnt is 0xF0(=240) in 64-bit section: xxd -seek 706(674 + 20 + 3 * 4) -len 4 data/Australia/Lord_Howe typecnt is 6 in 64-bit section: xxd -seek 710(706 + 4) -len 4 data/Australia/Lord_Howe So, 64-bit header has one extra transition type. Let’s check how it is used and what that transition is: 2638 = 674 + 44 + 240 * 8 xxd -seek 2638 -len 240 -c 1 data/Australia/Lord_Howe prints transition types: 00000b38: 05 . 00000b39: 04 . 00000b3a: 05 . 00000b3b: 04 . 00000b3c: 05 . 00000b3d: 01 . Transition type is changing from 4 to 5, but the last one is 1. xxd -seek 2878 -len 36 -c 6 data/Australia/Lord_Howe prints local time type records: 00000b3e: 0000 9524 0004 ...$.. 00000b44: 0000 0000 0000 ...... <- the last transition type 00000b4a: 0000 8ca0 0008 ...... 00000b50: 0000 a1b8 010d ...... 00000b56: 0000 93a8 0013 ...... 00000b5c: 0000 9ab0 0119 ...... Which means that 1st type’s offset is 0 and that the last rule for Lord Howe is actually GMT.

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[PROPOSED] Improve Palestine predictions for 2025 and later
by Paul Eggert Oct. 25, 2021

Oct. 25, 2021

* NEWS: Mention this. * asia (Palestine): Guess Fri>=23, not lastFri, for fallback transitions in the future. Fri>=23 is more consistent with past practice than lastFri. The first differing prediction is a fallback on 2025-10-24, not 2025-10-31. --- NEWS | 10 ++++++++++ asia | 2 +- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/NEWS b/NEWS index a7aa269..d83e01c 100644 --- a/NEWS +++ b/NEWS @@ -1,5 +1,15 @@ News for the tz database +Unreleased, experimental changes + + Changes to future timestamps + + Predict Palestine fallbacks to be the first Friday on or after + October 23, not October's last Friday, to be more consistent with + past practice. The first differing prediction is a fallback on + 2025-10-24, not 2025-10-31. + + Release 2021e - 2021-10-21 18:41:00 -0700 Changes to future timestamps diff --git a/asia b/asia index dd228e5..6d6b1de 100644 --- a/asia +++ b/asia @@ -3445,7 +3445,7 @@ Rule Palestine 2019 only - Mar 29 0:00 1:00 S Rule Palestine 2019 only - Oct Sat>=24 0:00 0 - Rule Palestine 2020 max - Mar Sat>=24 0:00 1:00 S Rule Palestine 2020 only - Oct 24 1:00 0 - -Rule Palestine 2021 max - Oct lastFri 1:00 0 - +Rule Palestine 2021 max - Oct Fri>=23 1:00 0 - # Zone NAME STDOFF RULES FORMAT [UNTIL] Zone Asia/Gaza 2:17:52 - LMT 1900 Oct -- 2.31.1

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Wrong name of timezone
by Igor Melnyk Oct. 25, 2021

Oct. 25, 2021

Hello! There is *Europe**/Kiev* timezone related to Ukraine. But Ukraine has the Ukrainian language and *Kiev* is in russian language. The correct name of the capital city of Ukraine is *Kyiv.* It must be changed. I know that it's not easy to do that but you must have some way to do that. For example, rename *Europe/Kiev* to *Europe/Kyiv* and make *Europe/Kiev* to be a temporary alias or link to *Europe/Kyiv.* What do you think about it? Best regards, Igor Melnyk.

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Re: [tz] Palestine winter time
by Paul Eggert Oct. 22, 2021

Oct. 22, 2021

On 10/21/21 01:03, heba.hamad(a)mtit.gov.ps wrote: > Could you please confirm that Palestine winter time has been adopted in IANA time zone database Yes, tzdb release 2021e was published today with the updated Palestine winter time. The announcement is archived here: https://mm.icann.org/pipermail/tz-announce/2021-October/000069.html

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[tz-announce] 2021e release of tz code and data available
by Paul Eggert via tz-announce Oct. 22, 2021

Oct. 22, 2021

The 2021e release of the tz code and data is available. This release reflects the following changes: Changes to future timestamps Palestine will fall back 10-29 (not 10-30) at 01:00. (Thanks to P Chan and Heba Hemad.) Here are links to the release files: https://www.iana.org/time-zones/repository/releases/tzcode2021e.tar.gz https://www.iana.org/time-zones/repository/releases/tzdata2021e.tar.gz https://www.iana.org/time-zones/repository/releases/tzdb-2021e.tar.lz The following convenience links are also available, although they may point to the previous release until the relevant caches are refreshed: https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz Links are also available via plain HTTP, and via FTP from ftp://ftp.iana.org/tz/releases with the same basenames as above. Each release file has a GPG signature, which can be retrieved by appending ".asc" to the above URLs. Copies of these signatures are appended to this message. This release corresponds to commit b102002e5300d94c369796d5b70bae22b5af720d dated 2021-10-21 18:41:00 -0700 and tagged '2021e' in the development GitHub repository at <https://github.com/eggert/tz>. Here are the SHA-512 checksums for the release files: 87b0335129ea41c5f42f687f548712e5da892baa8494cecf5d34851beceecf6ae52f22104696ed187713cf9e502570eb2041e277dfd3c043c11d0253bfde685a tzcode2021e.tar.gz c1e8d04e049157ed5d4af0868855bbd75517e3d7e1db9c41d5283ff260109de46b6fac6be94828201d093e163d868044ac2a9db2bf0aeab800e264d0c73a9119 tzdata2021e.tar.gz 8abd662f07a91eed5b77d03eaa3e9ef59ce08b4e3fc14f9857095c3d4f2039e8ac216fc985b0cf87a823eacad064197c8ecb76ba531a9fc700014d7f0057aba8 tzdb-2021e.tar.lz Here are the GPG digital signatures for the release files: -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFyF3cACgkQ7ZfpDmKq fjQKRw//c5HpFCN0vcPUIC/OQKTF/SXFOANCpHWypc/vgTVXFAsVu0zIKWdBuXXI 0zQDpbTcTJ2FfI5Z1JGNzeKa2G4Wy71lwwPu2mGDt0WCCAqh/l15XvgVEAM96YLG WZRK+WLKIVWgZ67NA2xWAt9VLgtA643Cgym1DCpsr9jTDAhGSYq8D0XC5OQHtfw2 oyzv4InTW+0EI14FQcQ3VqImLwGSefeYPfMBRjrAspqrTLez78vW914IWNKcgEoC pKCkq9+14u0L+G5j5E+f27gbRtZ4hZnIn5uNgItomJmGObW6khn0Huf+G6U1BAal 2zLSAYMubr1kq/6dP62QUivi1W2S3YRZDh20YsKxn214HW5qK5LdQKYruBGKOFou 7oAe91W3UW0vSJuboXj0Dbdc3p8Oay97eJ/kRDVKJZ95/UOQtwrkQi2wCbm19eC8 kvHdejbIrOvdl+ZpvkHIggQGSOchyXUASeqnX/9zirOAX0N05insC/ybJLAwepFm FqpvcfwjrJKCotAjFEEex1uIT5kgQwIumvtxLef3bGQgYtF1yfWMD0NSJAR1iAU2 BzXuikOLPNbHWpC41ODgRxBVaQnMpliC0WGJ/HiVT78ukEkx0MpcxyfnxjEDD7fz F3GlJlj/bw5rvsPrFzbSjYyzXfrn0u1y8/vgehUmtSj1K7MmB6I= =CliF -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFyF3cACgkQ7ZfpDmKq fjSLPw/9EDTMMp0ySiPkYgXICy+hYq78xDOpF5IU34tcvmL2j3OZiM49X//CQzNF 7kLoEkYenpjJZ9QU8V0w+26UJF3js/R3a9gLU3ybPZ7+o+NOanQK68z5EvggWGfm 0yVCGbPhsKNoP/2Xtpv3gLiT6WoBvJF6k16mRQtiE7ngLJ3OUpaWaQAZ73F+sMTY I5F++cAdTvOTHw6M4ORmvp8OMg2df1KVXf2MINQZkx3OVxw+y6zaMwcKUJHz81eY KCDO6DJyoj48/WNDxfIiYVk2YoOVm9I3HiqgmrojmniJFLCq/PkWGqU61gmNCSRv 5vLjb9qnfWQG8E3E44pdH8aqZt7z7kYdcL89y5UnDBlJMmoh/cPigjfBmAot7Erw 5Mj8pp/a7tcvHKIoGZscIzjRnffYDHTD6rNwStVvTfKyGE7O6Fa63yUnndCudqdu 6nZCQNkELrn9ber4ieJR6d46LOVFvqlMhCzhknZRUBkbtU4ltwBze8RvrGGhdyJ3 s9YQtGpY1uEcNF4JWzqkE9sXtPnevFERUT1hZdQpJ2NM0mrVKAfdLhryvJyi+t30 fbMbyqmYRhPuyk7OUPbduTIXc4IIpSzAaeQRFwZqDGSOuOj+8JSk6EX9Kwel7ahp 2PIzzyffxL7m2kG9+iAKckRHz0nyvoYGHQl1gsah9qUVx2Q/JIo= =kEHz -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFyF3cACgkQ7ZfpDmKq fjSLPw/9EDTMMp0ySiPkYgXICy+hYq78xDOpF5IU34tcvmL2j3OZiM49X//CQzNF 7kLoEkYenpjJZ9QU8V0w+26UJF3js/R3a9gLU3ybPZ7+o+NOanQK68z5EvggWGfm 0yVCGbPhsKNoP/2Xtpv3gLiT6WoBvJF6k16mRQtiE7ngLJ3OUpaWaQAZ73F+sMTY I5F++cAdTvOTHw6M4ORmvp8OMg2df1KVXf2MINQZkx3OVxw+y6zaMwcKUJHz81eY KCDO6DJyoj48/WNDxfIiYVk2YoOVm9I3HiqgmrojmniJFLCq/PkWGqU61gmNCSRv 5vLjb9qnfWQG8E3E44pdH8aqZt7z7kYdcL89y5UnDBlJMmoh/cPigjfBmAot7Erw 5Mj8pp/a7tcvHKIoGZscIzjRnffYDHTD6rNwStVvTfKyGE7O6Fa63yUnndCudqdu 6nZCQNkELrn9ber4ieJR6d46LOVFvqlMhCzhknZRUBkbtU4ltwBze8RvrGGhdyJ3 s9YQtGpY1uEcNF4JWzqkE9sXtPnevFERUT1hZdQpJ2NM0mrVKAfdLhryvJyi+t30 fbMbyqmYRhPuyk7OUPbduTIXc4IIpSzAaeQRFwZqDGSOuOj+8JSk6EX9Kwel7ahp 2PIzzyffxL7m2kG9+iAKckRHz0nyvoYGHQl1gsah9qUVx2Q/JIo= =kEHz -----END PGP SIGNATURE----- PS. If your tzdata parser does not yet support negative DST offsets or times past 24:00, or if it insists on a 'pacificnew' file that is no longer present, this release's data entries can be turned into a rearguard-format tarball that should work even with these older parsers. This is intended to be a temporary transition aid for these parsers. To generate a rearguard-format tarball, obtain the full distribution as described above, and run the command 'make rearguard_tarballs' on a development host. Or you can run 'make rearguard.zi' to generate a single file that can be fed directly to a parser that works like 'zic'.

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Re: [tz] Palestine winter time
by Paul Eggert Oct. 21, 2021

Oct. 21, 2021

On 10/20/21 01:47, heba.hamad(a)mtit.gov.ps wrote: > winter time will begin in Palestine from Friday 10-29 ,01:00 AM by 60 minutes backwards. Thank you for letting us know. Attached is a proposed change to tzdb, installed into its development version <https://github.com/eggert/tz>. We plan to have a new tzdb release soon. This change implements this year's transition, and also guesses that winter time will begin on October's last Friday at 01:00 in 2022 and later years, to be consistent with 2021. If this guess is wrong, please let us know as far in advance as possible, because rule changes trickle out only slowly to cell phones and computers.

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The origin of time zone regions
by Arthur David Olson Oct. 21, 2021

Oct. 21, 2021

A middling-length story with a small point. In the seventies and eighties, I helped develop two-dimensional PAGE* image analysis software. Black and white images had a thousand or so spots; the positions of the spots and their size provided information on the characteristics and abundances of proteins in samples. Step one was to get the positions and sizes of spots in a single image. Step two was to compare two images, pairing up the spots. Some spots would only appear in one image and have no pairs; in other cases, two (or more) spots would appear in one image where only one appeared in the other; one spot would be paired with multiple spots. The final step was to consider groups of images. For this purpose, there were groups of spots where (to quote an article on the matter) “each spot in a group is paired with some other spot in the group and no spot in any group is paired with any spot in any other group.” In the mid-eighties, work started on the time zone database. And time zone regions ended up being defined as being places where all the clocks agreed. The small point: the nature of time zone regions has less to do with chronometry or geopolitics than it does with gel analysis. @dashdashado _ * https://www.sciencedirect.com/topics/neuroscience/two-dimensional-gel-elect…

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Re: [tz] Pre-1970 data
by Stijn “Adhemar” Vandamme Oct. 20, 2021

Oct. 20, 2021

The “should timezones be merged when they contain identical offsets from 1970 onwards” discussion has been going on for quite a while on the tz mailing list. Still, contributions that I find insightful are still being made. Stephen Colebourne recently made this observation: > The key observation is that the segregation between these two groups > > of IDs *did not exist* until around 2014. It was only in 2018 that the > > ISO country rule was removed. > This change was reflected in the documentation <theory.html> as recently as 20/21 February 2019 < https://github.com/eggert/tz/commit/5f48dee82bc111b21f3610893e3b788e37396bce > < https://github.com/eggert/tz/commit/6176aefe79e83ddb8f255849b85c149f34d46aba > And Stephen made this spot-on point of analysis: > FWIW, it is clear to me that there is an aspect of imposing a > > US-centric timezone system on other parts of the world. The recent > > tzdb approach of focussing entirely on timezone regions makes perfect > > sense for the US, where region boundaries do not follow state lines, > > and ordinary members of the public need to be aware of whether they > > are in US/Mountain or US/Central. This simply isn't the timezone model > > in many other parts of the world. In places like Europe and Asia, the > > timezone is driven primarily by the country you live in - an ordinary > > member of the public in Iceland is never going to associate with some > > abstract timezone region stretching down the Atlantic that is not > > named, not legally defined and is little more than a random outcome > > based on tzdb's choice of 1970. Even in somewhere like Norway, an > > ordinary member of the public will understand that although they > > follow CET, their timezone is actually driven by their Government in > > Oslo. The brilliance of the original rule - "ID as needed for > > post-1970 data, with at least one per ISO country" - was that it > > seamlessly handled *both* models of timezone in one unified set of > > IDs. Removal of the ISO country part has completely destabilised that > > balance. > If I may throw in my two-penny, it would pertain to the documentation of this policy. Presently, <theory.html> does mention - that timezones are zones whose clocks all agree about timestamps that occur after the 1970 POSIX Epoch; - that 1970 is indeed a somewhat-arbitrary cutoff, but that moving it earlier even by a decade or two would impose significant challenges, due to the wide variety of local practices before computer timekeeping became prevalent; - that pre-1970 clock transitions are recorded for location-based timezones, but that the database is not designed for and does not suffice for applications requiring accurate handling of all past times everywhere; - that the previous “at-least-one-timezone-per-country-with-officially-designated-ISO-3166-1-two-letter-country-code” rule is dropped for this imposed too high a maintenance burden; and - that some information outside the scope of the database (implied: pre-1970) is collected in a file backzone that is distributed along with the database proper, but that this file is less reliable and does not necessarily follow database guidelines. What astonishes me in this issue is that high-quality information is being removed from the database proper into backzone, without this being mentioned in the documentation <theory.html>. Granted, <theory.html> does not explicitly state an “at-least-attempt-to-get-monotonically-closer-to-the-truth-with-increasing-versions” policy, but one would think that’s implied in maintaining a (versioned) database, unless explicitly stated otherwise. The other way around (moving information from backzone to the database proper, e.g. when historical information is double-checked and confirmed to be in accordance with database guidelines) is totally acceptable without mentioning in the documentation <theory.html>. Indeed, even though I know that correcting pre-1970 data is not the priority of this project, I’ve seen some great sluthing of historical time zone offsets presented on the tz mailing list in the past, and I kinda assumed that the results of such research found its way to the database proper (or backzone when doubts remained). In my opinion, removing high-quality information — thereby having correct offsets changed into incorrect offsets in information systems that rely on the tz database and keep it up-to-date on the default settings (which disregard backzone) — should cease, and should preferably be undone where such damage has already occured. Seeing how much problems pursuing “fairness” under the new rules causes, perhaps it’s worth reinstating the previous “at-least-one-timezone-per-country-with-officially-designated-ISO-3166-1-two-letter-country-code” rule, either officially or unofficially. (And for what it’s worth, this comes from someone who generally tries to avoid relying on country lists such as ISO 3166-1, due to strong political belief in the desirability of independence or at least increased self-governance for several countries/regions currently lacking an officially-designated ISO 3166-1 two-letter country code, including Flanders, Wallonia, Scotland, Catalonia, Basque Country, Canary Islands, Tibet, and others.) But alternatively, if this project persists in its “removing-high-quality-information and merging-for-merging’s-sake” policy, then at the very least this should be mentioned clearly, unambiguously and conspicuously highlighted (bold, bigger font size, bright but fully saturated background colour, following an animated warning icon, the lot) in the documentation <theory.html>: PREVIOUSLY OR CURRENTLY CORRECT PRE-1970 OFFSET INFORMATION IS > INTENTIONALLY BEING CHANGED AND/OR MAY INTENTIONALLY BE CHANGED IN LATER > VERSIONS OF THE tz DATABASE INTO INCORRECT OFFSET INFORMATION for the > braindead reason of merging timezones for merging’s sake. > USERS MUST NOT RELY ON UNDISPUTEDLY AND UNCONTESTEDLY CORRECT AND VERIFIED > OFFSET INFORMATION REMAINING CORRECT in the database proper, except for > timezones that have post-1970 particularities which prevent them from being > merged with foreign timezones. (And even then — who knows what the > coordinator-maintainer will come up with next…) > Information systems that rely on tz for offset information, including for > pre-1970 datetimes-with-timezone-identifier, ought to pass this warning on > to their users. > — Adhemar

1 0

Palestine winter time
by heba.hamad＠mtit.gov.ps Oct. 20, 2021

Oct. 20, 2021

Dear Sir, I’m Heba Hamad .I have been appointed as a focal point by the Ministry of telecommunication and information technology (state of Palestine) to communicate with you. We would like to inform you that winter time will begin in Palestine from Friday 10-29 ,01:00 AM by 60 minutes backwards. Kindly find the attachment below that includes the decision of the Palestinian cabinet. With Respects, Sent from Mail for Windows

4 4

Palestine winter time
by P Chan Oct. 18, 2021

Oct. 18, 2021

http://wafa.ps/Pages/Details/34701 https://www.facebook.com/wafagency/posts/4457787417632704 Palestine winter time will start from midnight 2021-10-29 (Thursday-Friday).

4 4

[tz-announce] 2021d release of tz code and data available
by Paul Eggert via tz-announce Oct. 15, 2021

Oct. 15, 2021

The 2021d release of the tz code and data is available. This release reflects the following changes, which were either circulated on the tz mailing list or are relatively minor technical or administrative changes: Briefly: Fiji suspends DST for the 2021/2022 season. 'zic -r' marks unspecified timestamps with "-00". Changes to future timestamps Fiji will suspend observance of DST for the 2021/2022 season. Assume for now that it will return next year. (Thanks to Jashneel Kumar and P Chan.) Changes to code 'zic -r' now uses "-00" time zone abbreviations for intervals with UT offsets that are unspecified due to -r truncation. This implements a change in draft Internet RFC 8536bis. Here are links to the release files: https://www.iana.org/time-zones/repository/releases/tzcode2021d.tar.gz https://www.iana.org/time-zones/repository/releases/tzdata2021d.tar.gz https://www.iana.org/time-zones/repository/releases/tzdb-2021d.tar.lz The following convenience links are also available, although they may point to the previous release until the relevant caches are refreshed: https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz Links are also available via plain HTTP, and via FTP from ftp://ftp.iana.org/tz/releases with the same basenames as above. Each release file has a GPG signature, which can be retrieved by appending ".asc" to the above URLs. Copies of these signatures are appended to this message. This release corresponds to commit 4de3d7f2499328c97e652242a36fed9523741d12 dated 2021-10-15 13:48:18 -0700 and tagged '2021d' in the development GitHub repository at <https://github.com/eggert/tz>. Here are the SHA-512 checksums for the release files: dbd7e3df02a11676600aa7efa14592feb2ac9ab5807b0d395e0c29ff1ed4a31580120287df9fe0c65a78162157dcd31d9fbe90a2a93bfd891d59ae3668a3adda tzcode2021d.tar.gz e25e85679256cfa57072cc8902aad1ca1df5ddc4a06844ca38bd57c8b5ad386e38303654dc85525f4fb470a924db4deb3576827a14d3ff87f4a1c679414b95c9 tzdata2021d.tar.gz 6ccb3ed6ebf35643cb49d503f18b7c66957de098f41870fd14ac37489b0931abd6d3e7bf5c2797e69f56f44b31ff9f9068ffa40f5aa29260ecda9d0aac878103 tzdb-2021d.tar.lz Here are the GPG digital signatures for the release files: -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFp6ekACgkQ7ZfpDmKq fjQtmBAApD1Am4P0gbEECXOABxrnE258QrPRqPhupj45gW0kMD5BehW+yO2oIzOU zDmgLbWyG5CmbD2lSt2fq1mZKhfqYD2J4QJlwwiPGHriNKZZCVIQniXZVRFUzQz/ oObtIzNm5mgR6OUhWDcbzYZsa10eJ7HTMrDOGViZ7T1DyLj5yobSXqkC/Q/ZlEvM Vpnl9nDieey2GgXvobfpR+Bby6NB26Pojjab9Mbw9jyRtcvnf6GmdBn6v4aoDwKc ZUqcb9qjv7NXnN5o9nCUSK7/ad+RoVZJAVDe84Quj1Vn8ydfZ0/1+i6bF3mM6Bpi I3riuPKkv7AHW2iRgZPnnqH7U+X32gb55/+WleokkasZj7e8i1QjJW7L0b91YOHN USz1McquYNsh/n9IDph4Zw1tBpbmLYAy3HQPaR6OzO8fc9paw5nsoics/5fQ5WoZ 2T2EavJfa045XKxwzd57w9YthQgW27Ep6UMpVCEGjYCBfVt8MfmiB787apGJdeJj NeVaKfSfpE4PTWvrtfTXPCIVIbIhlA5UUXyhEBXrMJw/FVxf8rAHGi/zvmrgl48X iY/xMG4yWpUYwZqWG0NBeGE0tvj8Yj2NagWj/UnGXcte3MvgmjkFSnKhj+UZrcA+ 1ehgE8pGicWEl0xl7uW6uwJ1IgWBMHYIkxpslJdTru+nnfbBIaA= =Bvd6 -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFp6ekACgkQ7ZfpDmKq fjTbSA/9HBEpib2dXzZg06u4WuVwFEbzu1AUblHm7I9PAzoxtTvJJqH0dMCrHDlj wldeHGclbBxLq8wF33Ajh7bvgISDhmjQCm/ux7nS0ctRnPkV4Pj2j6lsfk/gYVIB agFefLTTrdHaIrPxZ9TK7c63X+6HMfFDnE+nOrJXimls/gW/Xu/VeMDtngrCIoB3 JTSbPePbaSlA+NMn+RRhfb6jlw/Slbm7n5Zpf+VSZs2HN4+bNpHuFLbl5oMbPOrQ C+va/yKJXrNYroGOfIlz/ZnM24ZGDterLh9BBLe+zy3Ni+dhuH0x406C8zkZXSDu U1BZvHK3f84beSF0H1SbkGyjkfVSIol1o2p69mMdcyZzewng3n+MLB8lNxyMkmyk f8cTKviE0V+xoEe/yV8+0+uDhli+oLMudqNGy8eCRNgrnRkCsP513LMX73bagohQ xjtBd+cp2VSzhV4vXsJJE7mIwzofnZaGqdR/jyHND+4gx80TQo8Ftc29wRGbwCCI WU37r17EmcOPg+emOciIf8nYCPnIvKGBBZ0UcCEuvaZXXYhyg+2c82z7A+bIPZaS 6wQZhqptoWB07tJOMxcgCCV7I1fT8+GLlLLlJQXladooOa06mVzsFk8VlUX4PRl3 bIQGNgqRtoE/RnhbxgD0A4ToYUqdMvYzcoCGIGpg/4zmyFZWcaY= =NgZm -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFp6esACgkQ7ZfpDmKq fjSsWg/+NCtwn4E06FCtkR08EV0R8uG4xI6HyQc8JsB5DiFkt+evge2Bu+De03y5 nUJ1eaWbg27MLMfdYI7q5tET9G5RRcFUSZx5Zpj+Bv++KHEz7QSB5ZajE2n2qi93 AkXtFEQn8n0sCKbxdpikiUtKyZbIhcBZkzpAVU3sDdphoLUJFI2YPUCwNL5sPnzH 9pI9/iXCvu1mDW0Mg+mdBO6BuMVmTZneSJ+qtWVRvDPBvWJu8vDr16YiNaTYXkX6 atnvTDmjc3RP5DAjFzItBjsZWcLfrWWQ9WezYXWGDmJS+ijxSH0eYAUfXdHESMMd ggNwlsYZumla1p8yGmHP7YkUynds2hZYV8ySCZhfaCjq/AYANs2hzYLIY5reQ6mJ XxRoGOECc2uCmIVwFjYAALghW0GnDAy6M/l+qgzSxAr92Y0GdlFSdv8yWvIBYPyg /gFKrS+IkLHPJEF5vcpxCpCJC2XR2lJLAzoAgLUc14kD5enmVUjJzia8CpKahq2S argJwtnUl+pZT5QLfOSC46jG2o+RnhSarPSNb21cs+eNnPMA31aXDIRrGDCJ6UXf nRAU1t7eq4bbb/cvEGgJ9ZCfoQpBhYT4QO8as4JXnzkHrB7PuUiqw2sOXixF6H46 MSKRQq/uWI6XiAbXpUDFh67EeH/U1YkR8mx67Uii6pcGLvK2ptM= =Brw7 -----END PGP SIGNATURE----- PS. If your tzdata parser does not yet support negative DST offsets or times past 24:00, or if it insists on a 'pacificnew' file that is no longer present, this release's data entries can be turned into a rearguard-format tarball that should work even with these older parsers. This is intended to be a temporary transition aid for these parsers. To generate a rearguard-format tarball, obtain the full distribution as described above, and run the command 'make rearguard_tarballs' on a development host. Or you can run 'make rearguard.zi' to generate a single file that can be fed directly to a parser that works like 'zic'.

1 0

[PROPOSED 1/3] Document that -00 means local time is unspecified
by Paul Eggert Oct. 15, 2021

Oct. 15, 2021

* tzfile.5, zic.8: Document longstanding practice in time zone abbreviations. This better matches draft RFC 8536bis. --- tzfile.5 | 4 +++- zic.8 | 3 +++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/tzfile.5 b/tzfile.5 index 74564cb..e2f11b4 100644 --- a/tzfile.5 +++ b/tzfile.5 @@ -118,7 +118,9 @@ and serves as an index into the array of time zone abbreviation bytes that follow the .B ttinfo -structure(s) in the file. +entries in the file; if the designated string is "\*-00", the +.B ttinfo +entry is a placeholder indicating that local time is unspecified. The .B tt_utoff value is never equal to \-2**31, to let 32-bit clients negate it without diff --git a/zic.8 b/zic.8 index 3727922..89fc827 100644 --- a/zic.8 +++ b/zic.8 @@ -559,6 +559,9 @@ alphanumeric ASCII characters, .q "+" and .q "\*-". +By convention, the time zone abbreviation +.q "\*-00" +is a placeholder that means local time is unspecified. .TP .B UNTIL The time at which the UT offset or the rule(s) change for a location. -- 2.30.2

1 2

Kiev >> Kyiv
by Pavlo Komendant Oct. 12, 2021

Oct. 12, 2021

Hello, Could you please amend the Ukraine capital in the time zone? Kyiv is the correct spelling of the Ukraine capital https://en.wikipedia.org/wiki/Kyiv Thank you! -- Pavlo

3 2

Daylight Saving in Fiji Islands
by Jashneel Kumar Oct. 11, 2021

Oct. 11, 2021

Dear Support, Please note that there will be no daylight saving this year. Appreciate if the same can be reflected in your system to ensure that the time does not change. Looking forward to the confirmation. Regards, [New_VF_Icon_RGB_RED] Jashneel Kumar Manager Data Networks & Services Jashneel.Kumar(a)vodafone.com.fj<mailto:Jashneel.Kumar@vodafone.com.fj> Vodafone Fiji PTE Limited, 168 Princes Rd, Tamavua, Suva, Fiji Islands www.vodafone.com.fj<http://www.vodafone.com.fj/> Together we can [Vodafone] ________________________________ The content of this email including any attachments is confidential and may contain information that is proprietary and privileged. If you are not the intended recipient be advised that you have received this email in error and that any use, dissemination, forwarding, printing or copying of this email is strictly prohibited. If you have received this email in error please notify E-mail Administrator on info(a)vodafone.com.fj Please also destroy and delete this message from your system. Vodafone Fiji PTE Limited does not guarantee that this message is free from computer virus or any other defect. The reader accepts full responsibility for taking defensive and counteractive action needed to rectify the computer virus or other defects caused. Vodafone Fiji PTE Limited : Private Mail Bag, Suva, Fiji | Telephone : +679 3312000 | E-Mail : info(a)vodafone.com.fj Please consider your environmental responsibility before printing this e-mail [https://www.vodafone.com.fj//images/default-source/logo/logo-2x.png] Vodafone Fiji PTE Ltd <https://www.vodafone.com.fj/>

5 6

Typo in zic(8) man page
by Jonathan Wakely Oct. 8, 2021

Oct. 8, 2021

The description of a RULES field in a zone line says: "giving of the amount of time to be added" The first "of" looks like a typo.

2 1

Classifying IDs
by Stephen Colebourne Oct. 8, 2021

Oct. 8, 2021

Following on from the previous thread [1] I wanted to try and classify the IDs we have, which may or may not identify missing IDs. Again, please avoid talking about pre-1970 data at this point. Obsolete ------------ IDs that are obsolete and should never be used. They date from many years ago whe tzdb was just starting. Yet these still do appear in downstream UIs even today (of course UIs should not use the tzdb ID list, but in reality lots do). Examples: Portugal, NZ-CHAT, Navajo, Libya. Proposal: Provide 3-6 months notice, then move obsolete IDs to a new file "obsolete" which downstream projects are strongly encouraged not to include. (I would argue that the time has come to properly remove these IDs, which are very inconsistent in terms of which are provided and which not, eg Portugal, but not Spain) Deprecated, same location ------------------------------------ IDs that have been deprecated with a single clear alternative ID being provided. Both IDs represent the same physical location/city. Spelling changes: Asia/Katmandu (replaced by Asia/Kathmandu), Asia/Rangoon (replaced by Asia/Yangon) ID structure changes: America/Louisville (replaced by America/Kentucky/Louisville) Proposal: Ensure all of these are in `backward` Consider: Is there any way to move these IDs to the obsolete file? Maybe after 5 years? Or do we just accept backwards compatibility restrictions on these? Legally described mega-zones ----------------------------------------- IDs for locations where a federal or supra-national body defines rules, eg the EU or US DOT. Examples: US/Mountain, CET, WET Consider: Can we write down a rule to identify when something like this should be included? Then move the matching IDs to the main files (eg. are the EU and US DOT the only two examples here?) Regions ----------- IDs for abstract regions that have had the same wall clock since 1970. Examples: Europe/Berlin, America/New_York, Africa/Abidjan Proposal: Ensure all of these are in the main files. Consider: Should there be new IDs for each of these abstract regions to indicate they are a separate and distinct concept? eg. "Region/Berlin". (Maybe something to consider in future threads as it isn't clear what the benefit of doing so is without considering pre-1970 which I'm still trying to avoid) Non-region locations --------------------------- IDs for locations that are not region IDs. Each ID will have the same wall clock since 1970 as one of the region IDs. Examples: Europe/Oslo, Europe/Amsterdam, Atlantic/Reykjavik Consider: Can we write down a rule that covers which IDs are included here? And therefore when a new ID can be added to this set? If we can define a rule, then these can be split so rule-following IDs are in the main files and rule-breaking ones are in `backward` (although ideally they should be separate from the spelling changes). Obviously, we can say these IDs only exist for backwards compatibility, but that seems like a weak justification, and doesn't tackle the issue of when a new ID would be added to the list (which has been a point of tension). As is well known, I think the obvious rule is that the IDs follow the ISO-3166-1 standard (rule: one ID per ISO code, additional IDs may be added where clocks have diverged since 1970). Using ISO-3166 can be justified by IANA domain policy [2]: "We are not in the business of deciding what is and what is not a country. Instead, we employ a neutral standard maintained by the ISO 3166 Maintenance Agency. Our policy is to create new country-code top-level domains when the country or territory is listed on the ISO 3166-1 standard." As per the previous thread, these non-region location IDs are actively used in downstream business applications, and it is not OK that only works because tzdb happens to have IDs for backwards compatibility. There needs to be a better justification than that - these non-region locations need to be fully supported, with a consistent rule used to define what is and is not fully supported. Fixed/etc type rules -------------------------- IDs with a fixed offset Examples: GMT, UTC, Etc/GMT-9 Proposal: No change, retain in the main files unless a particular ID is considered obsolete or deprecated Are there any more classifications I've missed? Stephen [1] https://mm.icann.org/pipermail/tz/2021-September/030857.html [2] https://www.iana.org/help/eligible-tlds

7 17

Downstream use of 2021c
by Philip Paeps Oct. 8, 2021

Oct. 8, 2021

Since the tzdata 2021c release removed most of the controversial link changes, I wonder how other downstreams feel about importing it. I spent some time this morning looking at the downstreams I know about. FreeBSD has 2021c in main but is still on 2021a plus Samoa and Jordan in the supported stable branches. Debian is in the same state as FreeBSD. NetBSD, OpenBSD and Ubuntu are on 2021a + Samoa and Jordan. Fedora is on 2021b. CentOS is on 2021a. A casual glance at other Linux distributions shows they are either on 2021a or 2021c. I am not familiar with their support models so I can't read anything into that. Python "pytz" seems to be on 2021c. Python "tzdata" seems to be in a similar state to FreeBSD, though I'm not sure I'm interpreting the release model correctly. I know Paul G is on this mailing list though. As far as I can tell, PostgreSQL is still on 2021a without modifications for Samoa and Jordan. Tom will correct me if I'm reading that wrong. I don't know enough about PHP, Java or any of the other well-known (let alone less well-known) downstreams to figure out what they're doing. This is looking terribly fragmented. Spare a thought for a hypothetical engineer tasked with debugging a Java application on Debian with some Python scripts on Fedora talking to a PostgreSQL database running on FreeBSD... While discussions on this list appear to have become more constructive, it looks like we're still lacking a clear consensus on the long-term direction. I feel that 2021c is a pretty reasonable compromise and would be willing to merge it to the supported FreeBSD releases. Is this something other downstreams would consider too? Alternatively, can we reach an interim consensus for a 2021d release that we'd all be willing to merge? Philip -- Philip Paeps Senior Reality Engineer Alternative Enterprises

11 20

Use cases for source data
by Gilmore Davidson Oct. 8, 2021

Oct. 8, 2021

Stephen Colebourne's recent attempts to define requirements and use cases for tzdb got me thinking about the source data files. There have been several discussions over the years regarding the intended stability of the source format, separate from TZif binary files. These generally arise when the answer to a data query is "use this special compile-time flag". The most recent example is from Stephen at http://mm.icann.org/pipermail/tz/2021-September/030561.html The subtlety is in how the data set is consumed. While many downstream > projects use the makefile, not all do. A significant portion of > downstream users make use of the source files directly, with their own > parsers. ie. there is no ability to use a compile-time option. Those > parsers are not setup to use backzone even if it were a valid option > I think some of these discussions come about because there's disagreement about the intended use of the source files. The impression I've got from this list over the years is that the source files weren't intended to be a stable API; only the compiled TZif binary files were intended to be consumed downstream (and in later years, the .zi text representations). But many projects do use the source files as their primary interface, leading to tension when the format changes. So this is my attempt to list the use cases that people have for the source data files. This could prompt a wider discussion about what counts as a defined, stable interface for tzdb. Not every consumer of tzdb data is relying solely on the pre-compiled binary files. NOTE: This is a separate issue from the recent pre-/post-1970 data discussions. I'm trying to stay away from wading into that topic. ----------------------- Consumers of the source data text files: 1) The zic compiler for producing TZif binary files and .zi text files in an official tzdb release. 2) People reading the file comments to understand the history of certain zones. 3) Libraries/projects that need to parse/compile the data into a different representation than that provided by zic. This is often, but not exclusively, to preserve the distinction between Link and Zone entries, either for API or data compression reasons. 4) Data analysis or visualisations that care about knowing the higher-level Rule definitions ("transition on the last Sunday of October every year") rather than the exact transition timestamps for each year. 5) IDE or text editor plugins that provide syntax highlighting for the source files. All of these are based just on my own experiences and from lurking on this list. Any corrections/additions are welcome.

2 1

Re: [tz] On ISO country for timezones (Re: Classifying IDs)
by dpatte Oct. 7, 2021

Oct. 7, 2021

I believe you are missing an important part of this discussion.There is a strong need for a repository of pre 1970 data, especially for historical research applications. As this is the only tz database, tz has also become the main database for this older data.For any populated place on earth researchers need such a repository. If I want to add the pre 1970 tz history for Ottawa Canada where should it be stored? Since it is called tz, and it also has other pre 1970 data, tz seems the appropriate place.But if no simple method of adding open-ended historical data is negotiated here, then the only other option is to fork tz and work on it as a separate project.Secondly, since the number of locations that could eventually be supported in a historical tz database is potentially very large, it cannot not be micromanaged, and this suggests that each historical zone should use an international standard for naming - iso - for simplicity and clarity.Canada/Ontario/OttawaAre we going to have two tz databases, or just one. That is the question here.Sent from my Galaxy -------- Original message --------From: Steffen Nurpmeso via tz <tz(a)iana.org> Date: 2021-10-07 09:35 (GMT-05:00) To: Stephen Colebourne <scolebourne(a)joda.org> Cc: tz(a)iana.org Subject: Re: [tz] On ISO country for timezones (Re: Classifying IDs) Stephen Colebourne wrote in <CACzrW9Cau-q2e+yoBcg=7Rztu19zZN582Xca9ZMYbz=H_0iOpw(a)mail.gmail.com>: |On Thu, 7 Oct 2021 at 07:08, Watson Ladd via tz <tz(a)iana.org> wrote: ... |I agree with backwards compatibility. The primary concern here is |whether an ID is considered deprecated or not.IDs shall be stable and not change at all. At maximum they shouldbe moved to backward, for example if a zone is renamed (which mayhappen for example for Ukraine in a not too distant future, ifthat is still necessary then, and it looks as if it would be).I would always have been all for making infinite stability of IDsa documented assertion.Even if not, your "six months" claim is nothing but an aggressivestatement. I think this entire thread is shadowboxing and noisefor nothing.Looking at the interface of your JAVA framework i think getID()should simply return the correct ID, which may be a link if it isone, and just in case this is not what getID() already returns.In my opinion there are only two problems with IANA TZ and howPaul Eggert manages it as a maintainer. That is the same PaulEggert who contributes to this software since 1995, an astonishing26 years. Corroding the maintainership with a continuous streamof noise is disgusting.The first is combining of datasets to equal-post-1970 bundles,which is going on for many years. But the data is there, it is inbackzone, and everybody can easily install a complete TZ DB onone's own request. Yet noone did, even though many packagers areon this list. This is schizophrenic. But maybe it is onlybecause of black and yellow people do not matter as much as someblue-eyed white people from northern Europe, which does not trulycome as a surprise given the audience who possibly reads this now,and given the fact that colonianisation ended only about 55 yearsago, and de facto was only turned from armed political to armedmaterial oppression.The second is that documentation did not follow suit the codeimprovements, as has been recently shown for tzselect(8) and the-t option. That tzselect(8) uses the administrative zone1970.taband not the end-user-preferrable zone.tab is a different thing.If you want to enforce upon the maintainer of the TZ database thatthe pre-1970 data is joined back into the normal data, or that"backzone" is splitted into "backzone" and "unreliable", and/orthat "backzone" is included by default, and/or that "ZFLAGS='-r@0'" is made default, then create a thread and try to gain enoughhums, but please stop this subversion by spreading uncertainty andthat even upon topics which never were under discussion as far asi know, and i also read this list for a decade now.It must anyway be said it was nicer once i only had thedistribution and did not know about the list :)Ciao from Germany,--steffen||Der Kragenbaer, The moon bear,|der holt sich munter he cheerfully and one by one|einen nach dem anderen runter wa.ks himself off|(By Robert Gernhardt)

2 1

TZDB use cases
by Stephen Colebourne Oct. 7, 2021

Oct. 7, 2021

In this thread I want to try and capture the *requirements* for the project from the perspective of a downstream user. Given this, we may then have a chance to analyse whether the project needs a change of rules. NOTE: The discussion below is not a proposal, nor does it seek to explore which locations get pre-1970 data. Lets keep that for another thread. -------- 1) "What is the time now?" To answer this question you need a dataset that records the current timezone rules for each region in the world. Over time that data will naturally build up to form a historic record. To aid the project, a 1970 rule has been adopted for data management. In some parts of the world, clocks have agreed since 1970 across large parts of a continent. In other parts of the world, different parts of the same country have had different rules since 1970. Viewing the data through a post-1970 lens splits the planet into regions where clocks have agreed since 1970. Some of these regions are quite abstract, for example the region including Iceland, Ivory Coast, and St Helena. An abstract region would need to be split if one of the parts of the region changed its timezone rules. If a user had previously selected to follow one of these abstract regions, they might have to change their timezone settings. For example, if a user in Iceland selected their abstract region by the recommended ID based on the largest city they would get `Africa/Abidjan`, but if the Ivory Coast changed their rules, users in Iceland would have to change their selected timezone. The minimum set of IDs is one ID for each abstract region. The current ID scheme selects the largest city in the abstract region. My interpretation: * An abstract region should theoretically have an ID separate to the IDs of the cities/countries in the region * Trying the ID of the abstract region to the largest city in the region is prone to failure if that city changes timezone rules but the rest of the abstract region stays the same. * An abstract region ID would naturally have no pre-1970 data, as it doesn't define data in a single city/location. * The alternative is to encourage users to use their local city, which means that IDs like Europe/Amsterdam and Europe/Oslo cannot be deprecated -------- 2) "What was the time at some instant in the past?" The project can answer this question pretty reliably for dates from 1970 onwards because of the data set in #1. The project can never realistically answer the question reliably or accurately before 1970 for *all* locations. For example, timezone rules were entirely local in the US for about 20 years, meaning that hundreds of entries would be needed to correctly capture the data. In addition, much of the historic data globally is unknown and not viable to research, even if someone wanted to do so. It is possible to research and record historic timezone rules for *some* locations. Europe/London being one example. The project generally operates on the basis that if an ID exists, historical data can be recorded against it, although which file that data lives in has varied over time. IDs are generally not created solely to document historic data. There is no minimum set of IDs for this use case - the set of possible IDs is unbounded. My interpretation: * The majority of pre-1970 data isn't much use * Some pre-1970 data is high quality, and almost certainly relied upon (eg Europe/London) * Without a massive increase in scope the best that can be done pre-1970 is to record data against IDs created for some other reason. -------- 3) "An event will happen at this time in the future" If an end-user wants to store an event in the future, eg. a one hour meeting next month, the correct approach is to store the date, time and zone ID, not the offset (which is not yet known for certain).Even if the local timezone authority changes the tz rules between now and the event, the time of the event is still correct. https://stackoverflow.com/questions/19166995/java-calendar-date-and-time-ma… For this approach to work, the ID that is stored must be aligned with the timezone authority. Business contracts are frequently written to describe future events. For example, payment must be made by 2pm Paris time on a given date. The minimum set of IDs for this use case is one ID per timezone authority. This is typically the country but not necessarily, examples being decisions devolved to states/nations etc. My interpretation: * Using TZDB IDs for future events/contracts is very widespread * In most parts of the world, this requires one ID per country, in some parts of the world additional IDs would ideally be needed such as per state in the US * One ID for each ISO country (as was the guideline in the past) is a reasonable minimum expectation of end users * While one might argue IDs for future events are not TZDBs problem, I believe the reality is that they are because usage in this way is already very widespread -------- 4) "An event will happen at this time in the future relative to a shared/common definition" Some future events are declared relative to a definition that is supra-national or federal. For example, US Mountain, US Pacific, EU Central etc. A TV show might be defined to air at 8pm Mountain Time in one months time. It will air at that time regardless of whether any of the states that are currently on Mountain Time change to Pacific Time. For example, even if Denver (and Colorado) moved to Pacific Time or stopped following DST, Mountain Time would still exist and the TV show would still air at 8pm Mountain. The minimum set of IDs for this use case is one ID per shared/common definition. These IDs are not full aliases for a country or city ID, although they may currently share data. To support this use case, these IDs cannot be deprecated. My interpretation: * Some shared zone IDs are distinct and separate enough to warrant a full ID * US Mountain time is not the same as Denver time when considering the future, the IDs could diverge * In TZDB terms, the Link from US/Mountain to America/Denver is fine to define the data, but US/Mountain should not be considered deprecated as it has a real and distinct meaning separate from America/Denver * It would be useful to agree what the criteria for including these shared/federal rules is. -------- 5) "Data should be backwards compatible" The project has various associated downstream projects. Many of these have an expectation of backwards compatibility. This compatibility extends to the binary format, the source format, and the data contained within. This use case wants to see the project just continue with the data it has, enhancing it over time. The project has a pretty good record in terms of not removing IDs. For example, IDs exist for "Portugal" and "Poland", but not "Italy" or "Spain" simply because they were defined once upon a time. My understanding is that IDs in the `backward` file represent deprecated IDs that should not be used going forward. Yet, downstream projects focussed on backwards compatibility will generally use the `backward` file in full. The minimum set of IDs for this use case is the set of IDs that existed in the previous release. My interpretation: * Many users care about compatibility * The current IDs are not going away * Inconsistency has existed in TZDB for many years, see "Portugal" vs "Spain" - no one wants to fix that * It is hard at present to identify IDs that are deprecated because of proper aliasing, such as spelling changes, vs those where the ID is a real location but its TZDB status has been reduced. * Change may be possible with a long notice period --------- Please note that the above is not a proposal, but an exploration of the design space. If you have any use cases I've missed feel free to write them up. thanks Stephen

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timezone Verschlimmbesserung
by Tony Finch Oct. 6, 2021

Oct. 6, 2021

Paul Eggert's rationale is informative https://mm.icann.org/pipermail/tz/2021-September/030764.html But I think there are a few more things to say. The aim of merging timezones was to avoid political issues and to reduce the maintenance burden. It seems to me that it has failed to achieve those goals. There have been several very long discussions on the topic, and the recent arguments are making exactly the same points as were made in 2013. So I think the changes have increased the amount of political discussion and controversy on the tz list, not reduced it. https://mm.icann.org/pipermail/tz/2013-May/thread.html https://mm.icann.org/pipermail/tz/2013-August/thread.html https://mm.icann.org/pipermail/tz/2013-September/thread.html Paul says in his rationale that it was a lot of extra work, and in other messages he said that he has found it hard to keep up with the discussions. So merging timezones has increased the maintenance burden, not reduced it. I have identified two policy changes that caused this argument. In 2013, Paul Eggert started a new policy of merging timezones that are the same since 1970. As far as I can tell, no-one wanted this other than Paul. This merging policy was applied first to places with small populations, and (because of alphabetical order) to Africa, which is not well-represented by the people on the TZ list. Some of the merges also ignored the guideline that each country should have at least one timezone to call its own. The other policy change was to drop the guideline that each country should have at least one timezone. This change occurred in 2019, buried at the end of a very long discussion about Vietnam, and presented as a fait accompli. https://mm.icann.org/pipermail/tz/2019-February/027602.html This was after a great deal of discussion about the need to retain country information in the tz database, back in 2013 when these changes started. As I understand it, the equity / fairness issue is that the timezone merges were implemented in an unfair manner, affecting Africa (since 2014, against the guidelines as written at the time) but not Europe. So although Paul says the merges worked without significant incident, they did in fact cause a political complaint - exactly what the merges were supposed to avoid. The current argument was triggered by the question of whether this fairness issue should be addressed by undoing the data loss in the compiled tz files that caused the complaint, or by imposing the data loss more strictly. I think the way to fix this is to revert both policy changes, and revert all the timezone merges. Tony. -- f.anthony.n.finch <dot(a)dotat.at> https://dotat.at/ Lundy, Fastnet, Irish Sea: Northwest 4 to 6, backing southwest 5 to 7, perhaps gale 8 later. Slight or moderate until later in Irish Sea and Lundy, otherwise moderate or rough. Rain or showers. Good, occasionally poor.

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Italy April 1944 discrepancy between comment and data
by Alois Treindl Oct. 5, 2021

Oct. 5, 2021

For Italy in 1944 zone Europe/Rome there is a discrepancy between the comment and the data. comment: # From Paul Eggert (2016-10-27): # Go with INRiM for DST rules, except as corrected by Inglis for 1944 # for the Kingdom of Italy. This is consistent with Renzo Baldini. # Model Rome's occupation by using C-Eur rules from 1943-09-10 # to 1944-06-04; although Rome was an open city during this period, it # was effectively controlled by Germany. Data for Italy is Rule Italy 1944 only - Apr 2 2:00s 1:00 S Data for C-Eur is: Rule C-Eur 1944 1945 - Apr Mon>=1 2:00s 1:00 S where Mon>=1 in 1944 is April 3. So Rome is NOT following C-Eur. I think the rule for Itay is right, only the comment is misleading.

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legal status of information on TZ database
by nadir altinbas Oct. 5, 2021

Oct. 5, 2021

Hye, Is there a RFC document in which "explain rights and responsibilities of icann TZ coordination , about to solve regulation problems become from legal conflicts that third party person or company got and use of changes on TZ database country data by damage of their economic contracts agreement ?04.10.2021regards, Nadir Altinbasnadiraltinbas(a)yahoo.com n.altinbas

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