- tz - lists.iana.org

Reason for removal of several TZ
by Thomas M Steenholdt Jan. 23, 2018

Jan. 23, 2018

Hi guys, Almost a year ago, commit 2999bb5bee719acbba8b9dd50fb9fb00c7788623 removed several TZ abbreviations and I'm trying to understand this. For my own use, what I'm after is WGT/WGST which are now "simply -03". WGT/WGST has been in tzdata for a long time, so the removal causes certain things to go belly up. The change was only implemented in Ubuntu recently, which is why this only turned into a problem for me now. WGT/WGST seems to be a widely accepted abbreviation for the West Greenland Time zone. So can someone explain to me the reason behind the removal and what would needed to get it re-implemented? Thanks. /Thomas

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Irish Standard Time vs Irish Summer Time
by Neil Fuller Jan. 22, 2018

Jan. 22, 2018

Just to weigh in from an Android OS perspective: the Europe/Dublin DST convention change is also problematic for the Android platform. Most of what I would want to say has been said. Like many, I missed the discussion in December about this change and I'm not sure I would have grasped the full impact if I had. I monitor the announcements list so it would have been most useful to me if this change had been flagged ahead of time there. I started looking at 2018a when I saw discussion internally to Google and I was surprised I hadn't seen an official announcement. It might help to understand the impact of this change and the indirect influence and interactions that the tzdata has in Android so I've included some information below on my ongoing assessment as an FYI. The NITZ standard[1] is probably the worst interaction I've seen so far. In the meantime Android will probably have to take the same approach that ICU has and patch the IANA data, or wait for 2018c to hopefully reverse the convention back to what it was before. As always, thanks to all of you for keeping the world turning! Neil. ------------- The latest Android code is downstream from both OpenJDK and ICU, with some of it's own time zone code on the side. There is a custom implementation of classes like java.util.TimeZone, but also code for time zone detection used in smartphone devices. Android will be exposed to any problems that the ICU/OpenJDK maintainers mentioned, plus any in other OS libraries used that I haven't looked at yet. Android uses tzdata in some places for transition calculations, but refers to ICU for things like names. There may be other interactions. If the tzdata had one interpretation, and ICU had another, Android's formatting code might return (for example) Irish Standard Time in Winter. I found a long-standing bug in the Android java.util.TimeZone code that forces the DST adjustment to always be >= 0 and another elsewhere that (obviously incorrectly) assumes DST always means +1 hour. The time zone detection code on Android can use the time zone offset data it has available on device and compare it against information sent by the carrier via NITZ[1] to see if it can identify the user's time zone. The NITZ documentation says: "When the LTZ is compensated for DST (summertime), the serving PLMN shall provide a DST parameter to indicate this. The adjustment for DST can be +1h or +2h." I'm looking into whether carriers / networks in Ireland have made the same interpretation as the new IANA data. I suspect their hands are tied by the NITZ standard which would probably prevent them passing a negative number. There's probably a feedback loop here between the NITZ standard, what carriers will send and what devices can accept that might take a while to stabilize on any new convention, if it happens at all. >From a support perspective, Android has three cohorts to deal with: 1) Devices running older versions of Android for which OEMs are still providing over-the-air (OTA) system image updates. These can potentially take code patches to correct issues. 2) Devices running older versions of Android that have the ability to receive time zone rules data updates but not code. 3) Latest code under development for future Android releases. If the Europe/Dublin change "sticks" in tzdata, the likely course for supporting existing devices would be to patch the Android tzdata and pretend the Europe/Dublin shift hasn't happened. Future devices could potentially support negative DST adjustments if all the problems are caught in advance. [1] https://en.wikipedia.org/wiki/NITZ , see reference 1 for the standard I quoted -- Google UK Limited Registered Office: 6 Pancras Square, London, N1C 4AG Registered in England Number: 3977902

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Changing times
by Arthur David Olson Jan. 22, 2018

Jan. 22, 2018

In days of old, there was only one consumer of the time zone data files: the time zone compiler that's part of the IANA package. Today there are multiple consumers. My sense: that multiplication predominates over any change in maintenance approach as a complicating factor. @dashdashado

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The Japanese time zone rule is wrong.
by 二階隆幸 Jan. 22, 2018

Jan. 22, 2018

Hello, I'm Takayuki Nikai. I will report mistakes in Japanese time zone rules. Under Japanese law the daylight savings time boundary is written as 0:00, but tzdata is defined as 2:00. Also, the end of daylight saving time is Sunday, not Saturday. The source of information is Japanese law. http://www.shugiin.go.jp/internet/itdb_housei.nsf/html/houritsu/00219480428… http://www.shugiin.go.jp/internet/itdb_housei.nsf/html/houritsu/00719500331… > 四月の第一土曜日の午後十二時から九月の第二土曜日の翌日の午前零時までの間 > 第一条及び第二条第一項中「四月」を「五月」に改める。 In summary, it is written as follows. From 24:00 on the first Saturday in May, Until 0:00 on the day after the second Saturday in September. However, in Time Zone Database (2018a (Released 2018-01-12) which is currently distributed, it is starting from 2:00 as follows and it is wrong. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER / S Rule Japan 1948 only - May Sun>=1 2:00 1:00 D Rule Japan 1948 1951 - Sep Sat>=8 2:00 0 S Rule Japan 1949 only - Apr Sun>=1 2:00 1:00 D Rule Japan 1950 1951 - May Sun>=1 2:00 1:00 D I think that it will be correct as follows. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER / S Rule Japan 1948 only - May Sun>=1 0:00 1:00 D Rule Japan 1948 1951 - Sep Sun>=8 0:00 0 S Rule Japan 1949 only - Apr Sun>=1 0:00 1:00 D Rule Japan 1950 1951 - May Sun>=1 0:00 1:00 D An error will occur in past date time analysis. Please consider modification. -- +--------------------------------------------------------+ HealthCare Relations Co., Ltd. 二階隆幸 Nikai Takayuki 〒101-0054 東京都千代田区神田錦町3-13−7 名古路ビル本館1F TEL 042-485-7130 +--------------------------------------------------------+

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tzdb-2018b does not work after make clean
by 大山俊成 Jan. 22, 2018

Jan. 22, 2018

Hello, I'm Ohyama. I downloaded tzdb-2018b.tar.lz and did as followings make TOPDIR=$HOME/tzdir install $HOME/tzdir/usr/bin/zdump -v America/Los_Angeles it works good ! But once I do clean by make clean And again make TOPDIR=$HOME/tzdir install $HOME/tzdir/usr/bin/zdump -v America/Los_Angeles it does not works.(error message "America/Los_Angeles: No such file or directory") Something wrong with me?

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cppcheck in-efficiencies
by Khamit Ardashev Jan. 21, 2018

Jan. 21, 2018

I use cppcheck to scan my code, and it found these in-efficiencies, Could somebody fix them ? date/tz.cpp:755: performance: Variable 'u' is assigned in constructor body. Consider performing initialization in initialization list. date/date.h:7218: performance: Function parameter 'format' should be passed by reference. date/tz.cpp:220: performance: Function parameter 'path' should be passed by reference. date/tz.cpp:2417: performance: Function parameter 'format' should be passed by reference. Khamit Ardashev Flextrade Systems

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The Y2038 problem is 20 years away
by Tim Parenti Jan. 19, 2018

Jan. 19, 2018

It is now 03:14 UTC on 19 January 2018. Twenty years from now, POSIX and POSIX-based timestamps, which have more-or-less been counting seconds since 1970, will reach 2^31 and thus overflow signed 32-bit integers. Since all sorts of forward-looking date arithmetic abounds, it is inevitable that there are still active applications that will mishandle this. Twenty years out is an interesting point when more of those seams might start to show, and left unpatched, that would only increase as we approach 2038. It's much like Y2K, but in binary… and with seconds. So keep your eyes peeled in the near future for anything suddenly thinking it'll somehow be December 1901 in the slightly-more-distant future. You have some insight into just why that'll be happening. -- Tim Parenti

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Re: [tz] Irish Standard Time vs Irish Summer Time
by Patsy Franklin Jan. 19, 2018

Jan. 19, 2018

Hi, Will a resolution/patch be available for this soon? Thanks, Patsy

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video about Samoa's 2011 timezone switch
by Zefram Jan. 19, 2018

Jan. 19, 2018

An entertaining video about timezones, with particular reference to Samoa's 2011 move across the International Date Line: https://www.youtube.com/watch?v=rARMsjh4Zu0 -zefram

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broken compression in archive
by Zefram Jan. 18, 2018

Jan. 18, 2018

I'm doing some work on how to access historical tzdb versions, and I noticed that tz{code,data}94d.tar.Z are, despite their names, uncompressed tar files. To be precise, I refer to the files with these SHA-512 hashes: 9872b757ee3a8bf0ed3de1f0875f878b977b34bd2b60440b23a8c7308a7514d12a5d5d283387973e61b75e1a8eebd27009aab78eee4e12f1f1a5593f71941328 tzcode94d.tar.Z e1524951a5c261cc8eef1f3adadf5ebf8143293745fda9411a0090d6bb6e19f899dd7a6e55fe2f8f490a167a3da392020e49b369984bc1f5cbed87d664eb58de tzdata94d.tar.Z They're unique, in the present archive <ftp://ftp.iana.org/tz/releases/>, in having a mismatch between format and filename suffix. I think these files should be replaced, in the archive, with actual compressed (with compress(1)) versions of these tars, under the same name, so that the names are no longer misleading and they are in the same format as the surrounding files. The other way to make the names no longer misleading is to rename these files, dropping the ".Z" suffix, but this approach has the problem that these files would (still) have a different format from all the other tarballs. Note that this mismatch is not a mistake made in the original release of 94d, and the replacement that I'm proposing would not erase a record of the original release files. The original 94d release was of *gzipped* tar files, which are not in the present archive. Actual releases switched from .Z to .gz at 93g, but the archive files switch at tzdata95c and tzcode95d. Obviously someone recompressed the intervening tarballs somewhere along the chain of custody that led to the present archive, and it appears that the failure to (re)compress 94d happened in that process. -zefram

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Fwd: Issue with tzdata2018a.tar.gz Europe/Dublin Rule
by Vicky Jan. 18, 2018

Jan. 18, 2018

Hi, while parsing the data i found the issue in rule Europe/Dublin Negative DST.. Previous version or not in any other file there is no negative dst. DST either start and end . # The following is like GB-Eire and EU, except with standard time in # summer and negative daylight saving time in winter. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Eire 1971 only - Oct 31 2:00u -1:00 GMT Rule Eire 1972 1980 - Mar Sun>=16 2:00u 0 IST Rule Eire 1972 1980 - Oct Sun>=23 2:00u -1:00 GMT Rule Eire 1981 max - Mar lastSun 1:00u 0 IST Rule Eire 1981 1989 - Oct Sun>=23 1:00u -1:00 GMT Rule Eire 1990 1995 - Oct Sun>=22 1:00u -1:00 GMT Rule Eire 1996 max - Oct lastSun 1:00u -1:00 GMT Please explain why -ve dst offset compared with other files. Regards, Vaibhav

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Re: [tz] Build error on tzdb-2018a
by Paul Eggert Jan. 17, 2018

Jan. 17, 2018

Matias Fonzo wrote: > I can't update tzdb-2018a, I am getting this error: > > make: *** No rule to make target 'pacificnew', needed by 'version'. Thanks for reporting this packaging problem, which was not detected by the checks that I do before making a distribution. I have installed the attached patch to the development version; please give it a try. Because this problem was caught before I announced 2018a, I will hold off on making an announcement. Instead, I plan to wait a day or so for review of this patch, and then release 2018b with this patch.

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tzdata2018a released
by Seán Coffey Jan. 17, 2018

Jan. 17, 2018

It looks like 2018a has been released with a typo on the release date stamp : (Released 2010-01-12) [1] No announcement was sent to the announcement mailing list. Can the administration of such releases be made more transparent please ? The same type of admin issue happened during 2017. regards, Sean. [1] https://www.iana.org/time-zones

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Missing pacificnew data file
by Kerry Shetline Jan. 17, 2018

Jan. 17, 2018

Hi, I just downloaded the 2018a distribution of the tz database, with code. I tried to do a “make” and the make failed due to the missing pacificnew file. Copying that file from 2017c fixed the problem. The Java tool tzupdater also fails because of this missing file. I realize it might be that you are deliberately getting rid of this file, but your own make process is broken with the file missing, and I imagine other tools for updating time zone data besides tzupdater will also fail due to this file being gone. If you accidentally left pacificnew out, you might need to re-release the distribution. If getting rid of it was intentional, you’ll have to update your make process, or perhaps include a blank or commented-out copy of pacificnew. I also didn’t notice any changes in Brazil or Ireland as I expected to see from the release notes, which possibly is another problem. -Kerry

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Brazil moves DST start to November
by Steffen Thorsen Jan. 17, 2018

Jan. 17, 2018

According to many media sources, next year's DST start in Brazil will move to the first Sunday of November, and it will stay like that for the years after. Some examples in Portugese: https://noticias.r7.com/economia/por-eleicao-temer-reduz-periodo-de-horario… https://exame.abril.com.br/brasil/por-eleicao-temer-reduz-periodo-de-horari… We have made a brief English summary: https://www.timeanddate.com/news/time/brazil-delays-dst-2018.html Best regards, Steffen Thorsen - timeanddate.com

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Canada/East-Saskatchewan
by Derick Rethans Jan. 16, 2018

Jan. 16, 2018

Hi, I saw that the PHP build with the new timezone database (2017.3) failed due to Canada/East-Saskatchewan suddenly being gone. What's up with that? https://travis-ci.org/php/php-src/jobs/291636544#L1280 cheers, Derick -- https://derickrethans.nl | https://xdebug.org | https://dram.io Like Xdebug? Consider a donation: https://xdebug.org/donate.php twitter: @derickr and @xdebug

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leap-seconds.list file is out of date
by R. Bonomi Jan. 15, 2018

Jan. 15, 2018

The iana.org file only contains info through Bulletin C54, but Bulletin C55 is out. Reference: the leap-seconds.list file at usno.mil

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Mongolian time zone.
by Phake Nick Jan. 13, 2018

Jan. 13, 2018

Currently, tz database say Mongolia use UTC+7/8/9 as timezone. However, after quick google search, I found a question about time of Mongolia in a Mongolia question and answer time at [1]. The page itself is facing technical problem to me so I accessed it via Google cache which I subsequently thrown the cache into Google translate and archived the result at [2]. According to the page from 2016, three different users of the site answered the question with same answer, and all of them are saying Mongolia have three different timezone: 6, 7, 8. This is different from the information recorded in tz database. So, is the information in tz database incorrect? And then, another question on the site [3] (archived in [4]) asked about when did Mongolia start officially using the world time and someone answered since 1997. What does that mean? (On the other hand, another answer to a similar question say 1961... [5][6] or is that an error in machine translation?) [1]: http://acyy.mn/3379/монгол-улс-хэд-хэддүгээр-цагын-бүсэд-оршдог-вэ [2]: http://archive.is/y3jpH [3]: http://acyy.mn/8620/монгол-хэдэн-оноос-дэлхийн-бүсийн-цагийг-хэрэглэж-эхлэс… [4]: http://archive.is/PQBVk [5]: http://acyy.mn/7379/му-хэдэн-оноос-дэлхийн-цагийг-баримтлах-болсон-бэ [6]: http://archive.is/e39nW

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Sao Tome Principe change of time zone
by Steffen Thorsen Jan. 9, 2018

Jan. 9, 2018

Multiple sources tell that Sao Tome changed from UTC to UTC+1 as they entered the year 2018: https://www.dn.pt/lusa/interior/relogios-avancam-uma-hora-em-sao-tome-e-pri… http://pt.rfi.fr/sao-tome-e-principe/20180101-sao-tome-e-principe-muda-de-h… http://www.stp-press.st/2017/12/23/sao-tome-e-principe-vai-mudar-hora-a-par… So it seems the Africa/Sao_Tome zone needs to activated again! Our English summary: https://www.timeanddate.com/news/time/sao-tome-principe-time-zone-change.ht… Best regards, Steffen Thorsen - timeanddate.com

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[PATCH] * northamerica: Add note re Chicago time before 1883.
by Paul Eggert Jan. 8, 2018

Jan. 8, 2018

--- northamerica | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/northamerica b/northamerica index 505300a..a014126 100644 --- a/northamerica +++ b/northamerica @@ -348,6 +348,18 @@ Zone America/New_York -4:56:02 - LMT 1883 Nov 18 12:03:58 # Nebraska, eastern North Dakota, Oklahoma, eastern South Dakota, # western Tennessee, most of Texas, Wisconsin +# From Paul Eggert (2018-01-07): +# In 1869 the Chicago Astronomical Society contracted with the city to keep +# time. Though delayed by the Great Fire, by 1880 a wire ran from the +# Dearborn Observatory (on the University of Chicago campus) to City Hall, +# which then sent signals to police and fire stations. However, railroads got +# their time signals from the Allegheny Observatory, the Madison Observatory, +# the Ann Arbor Observatory, etc., so their clocks did not agree with each +# other or with the city's official time. The confusion took some years to +# clear up. See: +# Moser M. How Chicago gave America its time zones. Chicago. 2018-01-04. +# http://www.chicagomag.com/city-life/January-2018/How-Chicago-Gave-America-I… + # From Larry M. Smith (2006-04-26) re Wisconsin: # https://docs.legis.wisconsin.gov/statutes/statutes/175.pdf # is currently enforced at the 01:00 time of change. Because the local -- 2.7.4

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Three time zones meeting at one location
by Paul Eggert Dec. 29, 2017

Dec. 29, 2017

In yesterday's My Modern Met, Jessica Stewart says that in over 20 locations in the world, three different time zones converge. Surveyor Generals Corner in Australia and Treriksrøysa (for the point where Finland, Norway, and Russia meet) are two examples. For time zone hounds it may be an amusing read, if only to spot the mistakes. Stewart J. Places around the world where three time zones meet in the same spot. My Modern Met. 2017-12-28. https://mymodernmet.com/three-different-time-zones-facts/

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Lithuania calls on EU to stop adjusting clocks for daylight savings
by Lord Buddha Dec. 23, 2017

Dec. 23, 2017

https://www.theguardian.com/world/2017/dec/22/lithuania-calls-on-eu-to-stop…

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Transitions after those included in zoneinfo binaries?
by Paul G Dec. 21, 2017

Dec. 21, 2017

I recently noticed a discrepancy between the python-dateutil and pytz libraries when calculating offsets for dates after the last included transition in the zonefile binaries. What it boils down to is that when it runs out of transitions, python-dateutil selects the "standard" offset and pytz assumes that after the last transition the value "holds". In the southern hemisphere, this produces two different behaviors. Obviously there's no "right" answer here, since these are predictions about what time zones will be applied 20 years in the future (and even if the rules stayed the same, the "end date" is entirely artificial). Still, I wonder if it might be worth a bit of discussion and possibly a note in the Theory file? Barring a representation of the data that exposes the rules directly (in which case no such artificial limitation would be necessary), I think either fallback is defensible. Best, Paul

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Complexities of time rendered graphically
by Steve Jones Dec. 19, 2017

Dec. 19, 2017

Folks: Today's XKCD comic is amusing: https://xkcd.com/1930/ Steve Jones [image: Emacs!]

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default value of TZDEFAULT
by scs＠eskimo.com Dec. 18, 2017

Dec. 18, 2017

[This is a tzcode issue, not tzdata. Your regular discussion of zone definition and naming issues will resume shortly. :-) ] Consider this simple little program: #include <stdio.h> #include <time.h> int main() { time_t t = time(NULL); struct tm *tmp = localtime(&t); puts(asctime(tmp)); return 0; } There's nothing special about this program (that's the point). But suppose I download tzcode or tzdb and then compile the little program (call it lt.c) along with a just-built localtime(), like this: make localtime.o cc -o lt lt.c localtime.o But if I then run 'lt', it is likely not to work -- there's a pretty good chance it will print the current time in UTC, not my local time zone. If it fails, one reason is that it didn't successfully find my system's already-installed tz files. (That is, I made no attempt to build or install any new tz files.) The reason it didn't find them is obvious enough, and the Makefile contains all the hints I need: TOPDIR= /usr/local # "Compiled" time zone information is placed in the "TZDIR" directory # (and subdirectories). # Use an absolute path name for TZDIR unless you're just testing the software. # TZDIR_BASENAME should not contain "/" and should not be ".", ".." or empty. TZDIR_BASENAME= zoneinfo TZDIR= $(TOPDIR)/etc/$(TZDIR_BASENAME) And, sure enough, on my system, the already-installed tz files are not in /usr/local, they're in /usr/share. So it looks like if I change TOPDIR to /usr/share, or TZDIR to /usr/share/zoneinfo, I should be able to fix it. But no! It still doesn't work, and the reason is, my user environment doesn't have the TZ environment variable set; I'm assuming that the system's default time zone will be used. And, out of the box, the tzcode distribution assumes that the local time zone is defined by a file 'localtime' *in TZDIR*; that is, it essentially assumes that TZDEFAULT is $TZDIR/localtime. But some (perhaps even many) systems put it in /etc/localtime. That's where my (MacOS) system puts it, and a lot of Linux systems put it there, too. The upshot is that on such a system, if you compile and use localtime.c straight out of the tzcode distribution, it won't find your localtime file, and will end up falling back to UTC unless TZ is set. Since the Makefile already lets you set your own version of TZDIR (overriding the setting in tzfile.h), I think it makes sense to do the same thing for TZDEFAULT. Patch attached. With this patch in place, and with the Makefile edited to say TZDEFAULT = "/etc/localtime" fresh compiles of localtime.o correctly find my system's localtime file, and the lt program finally prints local time, as expected. (This tweak to TZDEFAULT's usage helps the extraction case -- that is, when the code tries to fetch the default zone, but not necessarily the tz file building case. I'm not sure whether 'make install' will do the right thing when TZDEFAULT is set, but it definitely doesn't do the right thing if DESTDIR and TZDEFAULT are both set. Is using DESTDIR supported? The Makefile should probably document it if so.) Diagnosing problems involving misconfigured TZDIR and TZDEFAULT variables can be surprisingly difficult. The localtime code doesn't have any way of telling you it's having trouble finding tz files in general, or the localtime file in particular. I'll address that issue in a separate thread. Steve Summit scs(a)eskimo.com

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