- tz - lists.iana.org

tzdb under the ASIS&T microscope
by Paul Eggert March 17, 2019

March 17, 2019

tzdb was the subject of an academic study published at the most recent annual meeting of the Association for Information Science & Technology: Hauser E. UNIX time, UTC, and datetime: Jussivity, prolepsis, and incorrigibility in modern timekeeping. Proc ASIS&T. 2018;55(1):161-70. https://doi.org/10.1002/pra2.2018.14505501018 For those of us not into the lingo, "jussivity" refers to how much a word or concept commands or exhorts us, and is related to the jussive mood of verbs in some languages. For example in the Latin phrase "doceas iter" ("teach the way") in the Aeneid, the mood of "doceas" means that people ought to teach the way. "Prolepsis" refers to foreshadowing, as in a proleptic calendar that is projected backward into the past or projected into the future. "Incorrigibility" refers to the property of a belief that a person cannot give up; here, the idea is that tzdb provides its own grounds for truth and its users can't (and don't want to) correct tzdb. As you can probably tell from my having to explain the words in the title, the tz mailing list was not the intended audience of this paper. Still, it can be amusing to see how outsiders see us.

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[PROPOSED] zic option for including data from a certain year onward
by Christopher Wong March 15, 2019

March 15, 2019

>From 4093e426a42421fd2d8579b07e8edb3fb116f561 Mon Sep 17 00:00:00 2001 From: Christopher Wong <christwo(a)axis.com> Date: Tue, 5 Feb 2019 15:02:57 +0100 Subject: [PATCH] zic.c: Add -k option to keep specified year and onward The -k option will take a year as input. It will strip away historical transition data before the specified year. The TZif files will be truncated. --- zic.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 69 insertions(+), 3 deletions(-) diff --git a/zic.c b/zic.c index 2ebc66a..9a3b1f5 100644 --- a/zic.c +++ b/zic.c @@ -178,6 +178,7 @@ static void mkdirs(char const *, bool); static void newabbr(const char * abbr); static zic_t oadd(zic_t t1, zic_t t2); static void outzone(const struct zone * zp, ptrdiff_t ntzones); +static zic_t ytime(zic_t year); static zic_t rpytime(const struct rule * rp, zic_t wantedy); static void rulesub(struct rule * rp, const char * loyearp, const char * hiyearp, @@ -610,6 +611,10 @@ static const char * leapsec; static const char * tzdefault; static const char * yitcommand; +/* This is used to truncate tzfiles. Only year specified by keepyear and + onward will be kept. Don't expect year to be outside range 0-9999. */ +static zic_t keepyear; + int main(int argc, char **argv) { @@ -640,7 +645,8 @@ main(int argc, char **argv) } else if (strcmp(argv[k], "--help") == 0) { usage(stdout, EXIT_SUCCESS); } - while ((c = getopt(argc, argv, "d:l:L:p:st:vy:")) != EOF && c != -1) + keepyear = ZIC_MIN; + while ((c = getopt(argc, argv, "d:k:l:L:p:st:vy:")) != EOF && c != -1) switch (c) { default: usage(stderr, EXIT_FAILURE); @@ -654,6 +660,22 @@ _("%s: More than one -d option specified\n"), return EXIT_FAILURE; } break; + case 'k': + if (keepyear == ZIC_MIN) { + keepyear = atoi(optarg); + /* Don't expect year to be outside range 0-9999. */ + if (keepyear < 0) + keepyear = 0; + if (keepyear > 9999) + keepyear = 9999; + } + else { + fprintf(stderr, +_("%s: More than one -k option specified\n"), + progname); + return EXIT_FAILURE; + } + break; case 'l': if (lcltime == NULL) lcltime = optarg; @@ -1749,7 +1771,7 @@ writezone(const char *const name, const char *const string, char version, register FILE * fp; register ptrdiff_t i, j; register int leapcnt32, leapi32; - register ptrdiff_t timecnt32, timei32; + register ptrdiff_t timecnt32, timei32, timei; register int pass; static const struct tzhead tzh0; static struct tzhead tzh; @@ -1865,6 +1887,37 @@ writezone(const char *const name, const char *const string, char version, --leapcnt32; ++leapi32; } + + timei = 0; + if (keepyear != ZIC_MIN) { + /* Discard transitions that happened before the keepyear. */ + int nbr_removes; + + nbr_removes = 0; + for (i = timei32; i < timecnt; ++i) + if (ats[i] < ytime(keepyear)) + ++nbr_removes; + timecnt32 -= nbr_removes; + timei32 += nbr_removes; + + nbr_removes = 0; + for (i = 0; i < timecnt; ++i) + if (ats[i] < ytime(keepyear)) + ++nbr_removes; + + if (nbr_removes > 0) { + /* Override the last removed transition time with the first transition + time that is the start point of the truncation range. Set defaulttype + to this first transition time. */ + --nbr_removes; + ats[nbr_removes] = ytime(keepyear); + defaulttype = types[nbr_removes]; + } + + timecnt -= nbr_removes; + timei += nbr_removes; + } + /* ** Remove old file, if any, to snap links. */ @@ -1910,7 +1963,7 @@ writezone(const char *const name, const char *const string, char version, thisleapi = leapi32; thisleapcnt = leapcnt32; } else { - thistimei = 0; + thistimei = timei; thistimecnt = timecnt; toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0; thisleapi = 0; @@ -3107,6 +3160,19 @@ tadd(zic_t t1, zic_t t2) } /* +** Given a year, compute the date (in seconds since January 1, +** 1970, 00:00). +*/ + +static zic_t +ytime(zic_t year) +{ + struct rule xr = { 0 }; + xr.r_dayofmonth = 1; + return rpytime(&xr, year); +} + +/* ** Given a rule, and a year, compute the date (in seconds since January 1, ** 1970, 00:00 LOCAL time) in that year that the rule refers to. */ -- 2.11.0 ?

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[PROPOSED] Fix 'make clean' problem with clean_*.dir
by Paul Eggert March 11, 2019

March 11, 2019

* Makefile (clean_misc, clean): Use rm -fr on patterns that can match directories, so that 'make clean' works even if there is a directory check_zishrink.dir. Stick with rm -f on patterns that should match only files, for safety. --- Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 4bc72a9..25f1d35 100644 --- a/Makefile +++ b/Makefile @@ -847,11 +847,13 @@ check_zishrink_posix check_zishrink_right: \ touch $@ clean_misc: + rm -fr check_*.dir rm -f *.o *.out $(TIME_T_ALTERNATIVES) \ check_* core typecheck_* \ date tzselect version.h zdump zic yearistype libtz.a clean: clean_misc - rm -fr *.dir *.zi tzdb-*/ $(TZS_NEW) + rm -fr *.dir tzdb-*/ + rm -f *.zi $(TZS_NEW) maintainer-clean: clean @echo 'This command is intended for maintainers to use; it' -- 2.20.1

1 0

Please remove tzdata2018f
by Ankur Rana March 11, 2019

March 11, 2019

Hello Paul/Team, While doing tzdata upgrade to version 2018f, we found below issue. java.lang.Exception: Failed while parsing file '/tmp/tz.tmp/asia' on line 1842 'Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S' at tools.tzdb.TzdbZoneRulesCompiler.parseFile(TzdbZoneRulesCompiler.java:377) at tools.tzdb.TzdbZoneRulesCompiler.compile(TzdbZoneRulesCompiler.java:191) at tools.tzdb.TzdbZoneRulesCompiler.<init>(TzdbZoneRulesCompiler.java:307) at com.sun.tools.tzupdater.ExternalModule.compileToJSRBinary(ExternalModule.java:226) at com.sun.tools.tzupdater.TimezoneUpdater.run(TimezoneUpdater.java:222) at com.sun.tools.tzupdater.TimezoneUpdater.main(TimezoneUpdater.java:643) Caused by: tools.tzdb.DateTimeException: Invalid value for SecondOfDay value: 90000 at tools.tzdb.ChronoField.checkValidValue(ChronoField.java:173) at tools.tzdb.LocalTime.ofSecondOfDay(LocalTime.java:210) at tools.tzdb.TzdbZoneRulesCompiler.parseMonthDayTime(TzdbZoneRulesCompiler.java:475) at tools.tzdb.TzdbZoneRulesCompiler.parseRuleLine(TzdbZoneRulesCompiler.java:399) at tools.tzdb.TzdbZoneRulesCompiler.parseFile(TzdbZoneRulesCompiler.java:354) ... 5 more We further found that the issue was addressed in version 2018g. To avoid any reoccurrence of same, would it be possible to prevent the tzdata version 2018f from downloading on iana site? [Ericsson]<http://www.ericsson.com/> ANKUR RANA Senior Software Developer Bussiness Area Digital Services - Development Unit Ericsson Block A, King Canyon "ASF Insignia" THE IT/ITES SEZ, Faridabad Road, Gawal Pahari, Gurgaon 122003, India Phone +91-124-3088600 Mobile +91-9811264594 ankur.rana(a)ericsson.com www.ericsson.com [http://www.ericsson.com/current_campaign]<http://www.ericsson.com/current_campaign> Legal entity: Ericsson India Global Services Pvt Ltd, registered office in Gurgaon. This Communication is Confidential. We only send and receive email on the basis of the terms set out at www.ericsson.com/email_disclaimer<http://www.ericsson.com/email_disclaimer>

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Why is `Etc/UCT` not an alias of `Etc/UTC`?
by Isiah Meadows March 10, 2019

March 10, 2019

They seem to refer to the same thing, so it doesn't make much sense to me why they're considered different. I also looked in the relevant file in the source, `/etcetera`, and there doesn't seem to be any rationale for it. Was this an oversight? ----- Isiah Meadows contact(a)isiahmeadows.com www.isiahmeadows.com

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Proposed Change to Maine's Time Zone *No Current Action Needed* Update
by C Yohman March 8, 2019

March 8, 2019

http://legislature.maine.gov/bills/getPDF.asp?paper=HP0659&item=1&snum=129 Text of No. 885, Rep. Baileys Proposal This one is light on substance too and impeded by: 15 United States Code, Section 260a https://www.law.cornell.edu/uscode/text/15/260a

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Proposed Change to Maine's Time Zone *No Current Action Needed* Update
by C Yohman March 8, 2019

March 8, 2019

Text of No. 144, Rep. Kessler's Proposal http://legislature.maine.gov/bills/getPDF.asp?paper=HP0126&item=1&snum=129 Seems light on substance. I remain firm that this likely goes nowhere.

1 0

Proposed Change to Maine's Time Zone *No Current Action Needed*
by C Yohman March 8, 2019

March 8, 2019

Long-time lurker, first time poster. I'm putting this on the periphery, in case it comes to pass (Probability: infinitesimal). Variations come about every decade. Not that it matters in this context, but the change would make sense for the eastern half of the state with commerce ties to New Brunswick and The Maritimes. Not so much for the western half of the state where the commerce ties are strong to New Hampshire & Massachusetts. That's just a slice of the perspective. Ironically, the two measures were introduced by two southern Maine representatives. Summary: "The two bills are proposed by Democratic lawmakers and take different approaches to eliminating the time change. Rep. Chris Kessler of South Portland’s bill would move Maine into the Atlantic time zone, which would mean the state would no longer set clocks back in fall. Rep. Donna Bailey, of Saco, has proposed keeping Maine in daylight saving time all year if the federal government also does so. Florida passed a similar bill." Source: https://www.pressherald.com/2019/03/07/bills-would-say-good-night-to-daylig… (Limited access. Google Chrome -> New Incognito Window is your option for multiple free views) Further Sources: https://wgme.com/news/local/bill-would-move-maine-into-atlantic-time-zone Rep. Kessler & Rep. Bailey have been contacted for the Reference LD # or further information. Sample email sent: Representative Kessler, Citizen of Waterboro, Maine here (work in Portland, commute through a sliver of South Portland), but I read your name is attached to one of the bills. "Rep. Chris Kessler of South Portland’s bill would move Maine into the Atlantic time zone, which would mean the state would no longer set clocks back in fall." https://www.pressherald.com/2019/03/07/bills-would-say-good-night-to-daylig… I have no opinion on the matter, but if there was a change there would likely need to be a change to tzdata, the database that keeps track of timezones across the world. https://www.iana.org/time-zones Ultimately, at a basic level, it allows you to set the correct timezone on your electronic devices. What is the LD number for the measure, or where can I read the proposed text to understand the proposed change better? Regards, Chance Yohman Follow-Up: Hearing scheduled for March 11th. Will update when I know.

1 0

Arbitrary default system time?
by Arthur David Olson March 7, 2019

March 7, 2019

A question about current operating systems. They have differing ways of establishing a system-wide default local time zone at installation time. Are the current ways flexible enough to allow establishing a zone that's not in the database (for example, Freedonia Standard Time--FST--for a newly created country)? (If not, adding a zic option to help with the matter might be of use.) @dashdashado

2 1

Re: [tz] Israel DST in 1980 and 1984 ?
by Alois Treindl March 7, 2019

March 7, 2019

-------- Forwarded Message -------- Subject: Re: [tz] Israel DST in 1980 and 1984 ? Date: Wed, 6 Mar 2019 20:49:56 +0200 From: Isaac Starkman To: Alois Treindl <alois(a)astro.ch> Dear Alois, It is correct. Summer time was in that period in 1980 and 1984, see https://www.ynet.co.il/articles/0,7340,L-3951073,00.html You can of course read it in translation. I checked the local newspapers for that years. It started on midnight and end at 01.00 am Isaac On Wed, Mar 6, 2019 at 6:42 PM Alois Treindl <alois(a)astro.ch <mailto:alois@astro.ch>> wrote: Dear Isaac, can you comment on the validity of this document? Best regards Alois -------- Forwarded Message -------- Subject: [tz] Israel DST in 1980 and 1984 ? Date: Wed, 6 Mar 2019 17:40:19 +0100 From: Alois Treindl <alois(a)astro.ch> <mailto:alois@astro.ch> To: tz(a)iana.org <mailto:tz@iana.org> I have been pointed to this document http://www.moin.gov.il/Documents/%D7%A9%D7%A2%D7%95%D7%9F%20%D7%A7%D7%99%D7… whose authenticity and origin I cannot affirm, lacking Hebrew. It concerns the years 1980 and 1984, 2 August 1980 - 13 Sept 1980 5 May 1984 - 25 August 1984 and claims that DST was in force during those periods.

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