April 2016 - tz - lists.iana.org

proposed time zone package changes (Samoa, Factory, et al.)
by Arthur David Olson 28 Aug '19

28 Aug '19

Below find proposed time zone package changes; the executive summary: * Makefile Change LOCALTIME default from "Factory" to "GMT"; do not compile "factory" file (but keep it in the distribution). * Theory Remove reference to "Factory" zone. * australasia Change end of DST in Samoa in 2011 from 2011-04-03 0:00 to 2011-04-03 1:00 (thanks to Raymond Hughes for a reference). * localtime.c Initialize ttinfo structures filled by tzparse (thanks to Ravindra for reporting a valgrind warning). * zic.c Fix generation of POSIX strings for zones with rules using "weekday<=n" forms of dates (thanks to Lei Liu for finding the problem). Also, limit output for non-POSIX-specificable zones defined to follow the same rules every year. (Note that no zones of either of the above types appear in the distribution; these changes cater to add-on zones). If no problems are found, 2010n will appear on 2010-10-25. --ado diff -r -c old/Makefile new/Makefile *** old/Makefile Mon Sep 27 09:24:25 2010 --- new/Makefile Tue Oct 12 12:36:50 2010 *************** *** 1,5 **** # <pre> ! # @(#)Makefile 8.8 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)Makefile 8.9 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 12,18 **** # make zonenames # to get a list of the values you can use for LOCALTIME. ! LOCALTIME= Factory # If you want something other than Eastern United States time as a template # for handling POSIX-style time zone environment variables, --- 12,18 ---- # make zonenames # to get a list of the values you can use for LOCALTIME. ! LOCALTIME= GMT # If you want something other than Eastern United States time as a template # for handling POSIX-style time zone environment variables, *************** *** 262,269 **** DOCS= README Theory $(MANS) date.1 Makefile PRIMARY_YDATA= africa antarctica asia australasia \ europe northamerica southamerica ! YDATA= $(PRIMARY_YDATA) pacificnew etcetera factory backward ! NDATA= systemv SDATA= solar87 solar88 solar89 TDATA= $(YDATA) $(NDATA) $(SDATA) TABDATA= iso3166.tab zone.tab --- 262,269 ---- DOCS= README Theory $(MANS) date.1 Makefile PRIMARY_YDATA= africa antarctica asia australasia \ europe northamerica southamerica ! YDATA= $(PRIMARY_YDATA) pacificnew etcetera backward ! NDATA= systemv factory SDATA= solar87 solar88 solar89 TDATA= $(YDATA) $(NDATA) $(SDATA) TABDATA= iso3166.tab zone.tab diff -r -c old/Theory new/Theory *** old/Theory Mon Sep 27 09:24:25 2010 --- new/Theory Tue Oct 12 12:36:50 2010 *************** *** 1,4 **** ! @(#)Theory 8.4 This file is in the public domain, so clarified as of 2009-05-17 by Arthur David Olson. --- 1,4 ---- ! @(#)Theory 8.5 This file is in the public domain, so clarified as of 2009-05-17 by Arthur David Olson. *************** *** 287,294 **** See the file `backward' for most of these older names (e.g. `US/Eastern' instead of `America/New_York'). The other old-fashioned names still supported are ! `WET', `CET', `MET', `EET' (see the file `europe'), ! and `Factory' (see the file `factory'). ----- Time zone abbreviations ----- --- 287,293 ---- See the file `backward' for most of these older names (e.g. `US/Eastern' instead of `America/New_York'). The other old-fashioned names still supported are ! `WET', `CET', `MET', and `EET' (see the file `europe'). ----- Time zone abbreviations ----- diff -r -c old/australasia new/australasia *** old/australasia Mon Sep 27 09:24:27 2010 --- new/australasia Tue Oct 12 13:14:56 2010 *************** *** 1,5 **** # <pre> ! # @(#)australasia 8.18 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)australasia 8.19 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 487,497 **** # http://www.parliament.gov.ws/documents/acts/Daylight%20Saving%20Act%20%2020… # </a> Zone Pacific/Apia 12:33:04 - LMT 1879 Jul 5 -11:26:56 - LMT 1911 -11:30 - SAMT 1950 # Samoa Time -11:00 - WST 2010 Sep 26 ! -11:00 1:00 WSDT 2011 Apr 3 -11:00 - WST # Solomon Is --- 487,507 ---- # http://www.parliament.gov.ws/documents/acts/Daylight%20Saving%20Act%20%2020… # </a> + # From Raymond Hughes (2010-10-07): + # Please see + # <a href="http://www.mcil.gov.ws"> + # http://www.mcil.gov.ws + # </a>, + # the Ministry of Commerce, Industry and Labour (sideframe) "Last Sunday + # September 2010 (26/09/10) - adjust clocks forward from 12:00 midnight + # to 01:00am and First Sunday April 2011 (03/04/11) - adjust clocks + # backwards from 1:00am to 12:00am" + Zone Pacific/Apia 12:33:04 - LMT 1879 Jul 5 -11:26:56 - LMT 1911 -11:30 - SAMT 1950 # Samoa Time -11:00 - WST 2010 Sep 26 ! -11:00 1:00 WSDT 2011 Apr 3 1:00 -11:00 - WST # Solomon Is diff -r -c old/localtime.c new/localtime.c *** old/localtime.c Mon Sep 27 09:24:26 2010 --- new/localtime.c Tue Oct 12 12:36:51 2010 *************** *** 5,11 **** #ifndef lint #ifndef NOID ! static char elsieid[] = "@(#)localtime.c 8.14"; #endif /* !defined NOID */ #endif /* !defined lint */ --- 5,11 ---- #ifndef lint #ifndef NOID ! static char elsieid[] = "@(#)localtime.c 8.15"; #endif /* !defined NOID */ #endif /* !defined lint */ *************** *** 914,919 **** --- 914,920 ---- register unsigned char * typep; register char * cp; register int load_result; + static struct ttinfo zttinfo; INITIALIZE(dstname); stdname = name; *************** *** 986,991 **** --- 987,993 ---- /* ** Two transitions per year, from EPOCH_YEAR forward. */ + sp->ttis[0] = sp->ttis[1] = zttinfo; sp->ttis[0].tt_gmtoff = -dstoffset; sp->ttis[0].tt_isdst = 1; sp->ttis[0].tt_abbrind = stdlen + 1; *************** *** 1099,1106 **** } /* ** Finally, fill in ttis. - ** ttisstd and ttisgmt need not be handled. */ sp->ttis[0].tt_gmtoff = -stdoffset; sp->ttis[0].tt_isdst = FALSE; sp->ttis[0].tt_abbrind = 0; --- 1101,1108 ---- } /* ** Finally, fill in ttis. */ + sp->ttis[0] = sp->ttis[1] = zttinfo; sp->ttis[0].tt_gmtoff = -stdoffset; sp->ttis[0].tt_isdst = FALSE; sp->ttis[0].tt_abbrind = 0; *************** *** 1113,1118 **** --- 1115,1121 ---- dstlen = 0; sp->typecnt = 1; /* only standard time */ sp->timecnt = 0; + sp->ttis[0] = zttinfo; sp->ttis[0].tt_gmtoff = -stdoffset; sp->ttis[0].tt_isdst = 0; sp->ttis[0].tt_abbrind = 0; diff -r -c old/zic.c new/zic.c *** old/zic.c Mon Sep 27 09:24:26 2010 --- new/zic.c Tue Oct 12 13:37:29 2010 *************** *** 3,9 **** ** 2006-07-17 by Arthur David Olson. */ ! static char elsieid[] = "@(#)zic.c 8.22"; #include "private.h" #include "locale.h" --- 3,9 ---- ** 2006-07-17 by Arthur David Olson. */ ! static char elsieid[] = "@(#)zic.c 8.24"; #include "private.h" #include "locale.h" *************** *** 1881,1896 **** register int week; if (rp->r_dycode == DC_DOWGEQ) { ! week = 1 + rp->r_dayofmonth / DAYSPERWEEK; ! if ((week - 1) * DAYSPERWEEK + 1 != rp->r_dayofmonth) return -1; } else if (rp->r_dycode == DC_DOWLEQ) { if (rp->r_dayofmonth == len_months[1][rp->r_month]) week = 5; else { ! week = 1 + rp->r_dayofmonth / DAYSPERWEEK; ! if (week * DAYSPERWEEK - 1 != rp->r_dayofmonth) return -1; } } else return -1; /* "cannot happen" */ (void) sprintf(result, "M%d.%d.%d", --- 1881,1896 ---- register int week; if (rp->r_dycode == DC_DOWGEQ) { ! if ((rp->r_dayofmonth % DAYSPERWEEK) != 1) return -1; + week = 1 + rp->r_dayofmonth / DAYSPERWEEK; } else if (rp->r_dycode == DC_DOWLEQ) { if (rp->r_dayofmonth == len_months[1][rp->r_month]) week = 5; else { ! if ((rp->r_dayofmonth % DAYSPERWEEK) != 0) return -1; + week = rp->r_dayofmonth / DAYSPERWEEK; } } else return -1; /* "cannot happen" */ (void) sprintf(result, "M%d.%d.%d", *************** *** 2018,2023 **** --- 2018,2024 ---- register char * envvar; register int max_abbr_len; register int max_envvar_len; + register int prodstic; /* all rules are min to max */ max_abbr_len = 2 + max_format_len + max_abbrvar_len; max_envvar_len = 2 * max_abbr_len + 5 * 9; *************** *** 2032,2037 **** --- 2033,2039 ---- timecnt = 0; typecnt = 0; charcnt = 0; + prodstic = zonecount == 1; /* ** Thanks to Earl Chew ** for noting the need to unconditionally initialize startttisstd. *************** *** 2053,2058 **** --- 2055,2062 ---- updateminmax(rp->r_loyear); if (rp->r_hiwasnum) updateminmax(rp->r_hiyear); + if (rp->r_lowasnum || rp->r_hiwasnum) + prodstic = FALSE; } } /* *************** *** 2075,2080 **** --- 2079,2094 ---- if (max_year <= INT_MAX - YEARSPERREPEAT) max_year += YEARSPERREPEAT; else max_year = INT_MAX; + /* + ** Regardless of any of the above, + ** for a "proDSTic" zone which specifies that its rules + ** always have and always will be in effect, + ** we only need one cycle to define the zone. + */ + if (prodstic) { + min_year = 1900; + max_year = min_year + YEARSPERREPEAT; + } } /* ** For the benefit of older systems,

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Syntax highlighting for Sublime Text
by Gilmore Davidson 16 Aug '17

16 Aug '17

Hi, I’ve created some tzdata syntax highlighting rules for the Sublime Text editor: https://packagecontrol.io/packages/zoneinfo <https://packagecontrol.io/packages/zoneinfo> I have no idea if anyone other than me uses that particular text editor for looking at tzdata files. But I thought I’d mention it just in case it’s useful to someone. Cheers, Gil

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Re: [tz] Version in zoneinfo files?
by Guy Harris 10 Feb '17

10 Feb '17

On Oct 25, 2015, at 10:55 AM, Paul G <paul(a)ganssle.io> wrote: > I'm not suggesting that it be impossible to create a weird result when asking for the version, just that there's a standard place for the version to go, and preferably the standard default gives you something that you expected. I.e., something that works most of the time is sufficient? So what exactly is the intended use of this version field? > As it is now, you're virtually guaranteed to have a lot of incompatibility because there's nothing you can point to that says, "This is the canonical way to store version information about zoneinfo files", and no standard has emerged on how to do this as is. > > On 10/25/2015 01:51 PM, Guy Harris wrote: >> >> On Oct 25, 2015, at 10:37 AM, Paul G <paul(a)ganssle.io> wrote: >> >>> On 10/25/2015 01:35 PM, Guy Harris wrote: >>> >>>> So where would zic get the version information to put into the binary files? >>> >>> My understanding is that it's the VERSION= line of the Makefile in the tzdata tarballs. >> >> I.e., you're proposing that the value of the VERSION value in the Makefile be passed as an argument to zic, and zic would put the value of that argument into a field in the files? >> >> So, if the goal is to provide a "reliable way to get the version information in a cross-platform way", what would ensure that this field be set properly, for some value of "properly", everywhere that binary tzdata files are generated? >> >> I.e., what is to guarantee that >> >> 1) nobody downstream change VERSION if they aren't changing the zic files from what's distributed >> >> and >> >> 2) people change it "properly" if the files don't correspond to a particular version of files that were distributed (e.g., if some downstream supplier takes 2015q and adds some changes mentioned on the list to it before 2015r comes out with those changes plus other changes, they should call the resulting files something other than "2015q" or "2015r")? >> >

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Proposal: validation text file with releases
by Jon Skeet 19 Dec '16

19 Dec '16

Background: I'm the primary developer for Noda Time <http://nodatime.org> which consumes the tz data. I'm currently refactoring the code to do this... and I've come across some code (originally ported from Joda Time) which I now understand in terms of what it's doing, but not exactly why. For a little while now, the Noda Time source repo has included a text dump file <https://github.com/nodatime/nodatime/blob/master/src/NodaTime.Test/TestData…>, containing a text dump of every transition (up to 2100, at the moment) for every time zone. It looks like this, picking just one example: Zone: Africa/Maseru LMT: [StartOfTime, 1892-02-07T22:08:00Z) +01:52 (+00) SAST: [1892-02-07T22:08:00Z, 1903-02-28T22:30:00Z) +01:30 (+00) SAST: [1903-02-28T22:30:00Z, 1942-09-20T00:00:00Z) +02 (+00) SAST: [1942-09-20T00:00:00Z, 1943-03-20T23:00:00Z) +03 (+01) SAST: [1943-03-20T23:00:00Z, 1943-09-19T00:00:00Z) +02 (+00) SAST: [1943-09-19T00:00:00Z, 1944-03-18T23:00:00Z) +03 (+01) SAST: [1944-03-18T23:00:00Z, EndOfTime) +02 (+00) I use this file for confidence when refactoring my time zone handling code - if the new code comes up with the same set of transitions as the old code, it's probably okay. (This is just one line of defence, of course - there are unit tests, though not as many as I'd like.) It strikes me that having a similar file (I'm not wedded to the format, but it should have all the same information, one way or another) released alongside the main data files would be really handy for *all* implementors - it would be a good way of validating consistency across multiple platforms, with the release data being canonical. For any platforms which didn't want to actually consume the rules as rules, but just wanted a list of transitions, it could even effectively replace their use of the data. One other benefit: diffing the dump between two releases would make it clear what had changed in *effect*, rather than just in terms of rules. One sticking point is size. The current file for Noda Time is about 4MB, although it zips down to about 300K. Some thoughts around this: - We wouldn't need to distribute it in the same file as the data - just as we have data and code file, there could be a "textdump" file or whatever we'd want to call it. These could be retroactively generated for previous releases, too. - As you can see, there's redundancy in the format above, in that it's a list of "zone intervals" (as I call them in Noda Time) rather than a list of transitions - the end of each interval is always the start of the next interval. - For zones which settle into an infinite daylight saving pattern, I currently generate from the start of time to 2100 (and then a single zone interval for the end of time as Noda Time understands it; we'd need to work out what form that would take, if any). If we decided that "year of release + 30 years" was enough, that would cut down the size considerably. Any thoughts? If the feeling is broadly positive, the next step would be to nail down the text format, then find a willing victim/volunteer to write the C code. (You really don't want me writing C...) Jon

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Blog Post: On the Timing of Time Zone Changes
by Matt Johnson 25 Jul '16

25 Jul '16

I've written a blog post describing the chaos that ensues when governments don't provide enough notice of their changes to time zones. http://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-changes/ <http://aka.ms/weboutlook> Enjoy! -Matt

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Egypt to have DST again
by Steffen Thorsen 02 Jul '16

02 Jul '16

Several of our users have reported on new DST plans in Egypt, which is confirmed by several sources that all say Egypt will have DST from July 7 until the end of October. Unfortunately, "end of October" is very vague, but we at timeanddate.com would assume a rule like this for it, based on their historic end dates: Rule Egypt 2016 max - Oct lastThu 23:00s 0 - We also assume it will start at the end of July 7 (midnight between Thursday and Friday). http://english.ahram.org.eg/NewsContentP/1/204655/Egypt/Daylight-savings-ti… http://www.nileinternational.net/en/?p=25806 I found it interesting that EgyptAir seems to have assumed DST to start in April (like it previously did in 2010), and therefore this obviously causes problems with the schedules: http://www.egyptair.com/en/about-egyptair/news-and-press/Pages/CANCELLATION… Best regards, Steffen Thorsen - timeanddate.com

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Re: [tz] YouTube videos on time zones
by Steve Jones 30 May '16

30 May '16

At 01:14 PM 3/8/2016, Matt Johnson wrote: >If these two aren't in our art file, they probably should be. One mustn't forget the trailer for "Daylight Saving", the movie: https://www.youtube.com/watch?v=k4EUTMPuvHo Regards, Steve Jones

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New time zone library
by Matt Johnson 29 May '16

29 May '16

Please add to the tz-link file under Other tz compilers: Lau's Tzdata library for the Elixir language automatically downloads and compiles tz source data, and exposes APIs for use. It is freely available under the MIT license. https://github.com/lau/tzdata Thanks, Matt

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Programmatic way of determining the latest release number?
by Jon Skeet 30 Apr '16

30 Apr '16

Hi folks, I'm aware of the ability to use ftp://ftp.iana.org/tz/tzcode-latest.tar.gz and the similar data URL to get the latest actual files, but is there a URL which either serves an HTTP redirect to the latest version, or gives the latest version number in some other easily-retrievable machine-readable format? I could parse the content of http://www.iana.org/time-zones, but that doesn't feel like a very robust approach :) Presumably this might all drop out of the tzdist work, but I was wondering whether there was a low-tech way at the moment. Jon

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Re: [tz] Issue in Time Zone Database for Kazakhstan's zones
by Paul Eggert 29 Apr '16

29 Apr '16

On 04/28/2016 10:27 AM, Zhanibek Adilbekov wrote: > > formats of zones are changed, e.g. for Asia/Almaty it changed from > ALMT to +06. I'm not familiar with TZ files, but I suppose this > changes are the reason of incompatibility for some apps. > Yes, I think that's relevant to the Plasma Digital Clock bug. I found what appears to be a related bug in the way that Qt handles data from tz 2016b, so the problem is not limited to tz 2016d. I can reproduce the problem by using just the Qt base, without involving KDE or Plasma. The Qt base parses tz data directly (!), and appears to do so incorrectly. I have filed a Qt bug report here: https://bugreports.qt.io/browse/QTBUG-53071 zic.c already has workarounds for buggy programs that misparse tzdata files containing time stamps far in the past, by putting in a no-change transition before the Big Bang. Perhaps there could be a similar workaround for this Qt bug, as Qt appears to mishandle tzdata files where the predicted future uses a POSIX TZ string that assumes POSIX.1-2001 or later. That is, perhaps we can work around the Qt bug by appending to the binary data some sort of no-change transition far enough in the future that we can expect Qt to be fixed in the field before most users care about those future time stamps. The year 2116, say?

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