[tz] zdump bug in Asia/Singapore

[Arthur David Olson]

The attached change (which also appears in tab-mangled form below) dealt
with the problem on the system I'm using. It arranges things so that when
the step-by-half-a-day time value goes over the maximum cutoff time, a
final transition test is made.

(This seems better than excusing the behavior based on zdump.8's language
about cutoffs being "near the starts of the years.")

    @dashdashado

1.1
927 lines
1.2
927 lines
*** /tmp/,azdump.c    2014-09-06 19:56:41.335772400 -0400
--- /tmp/,bzdump.c    2014-09-06 19:56:41.423777400 -0400
***************
*** 654,665 ****
          tmp = my_localtime_rz(tz, &t, &tm);
          if (tmp)
            ab = saveabbr(&abbrev, &abbrevsize, &tm);
!         for ( ; ; ) {
              newt = (t < absolute_max_time - SECSPERDAY / 2
                  ? t + SECSPERDAY / 2
                  : absolute_max_time);
              if (cuthitime <= newt)
!                 break;
              newtmp = localtime_rz(tz, &newt, &newtm);
              if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
                  (delta(&newtm, &tm) != (newt - t) ||
--- 654,665 ----
          tmp = my_localtime_rz(tz, &t, &tm);
          if (tmp)
            ab = saveabbr(&abbrev, &abbrevsize, &tm);
!         while (t < cuthitime) {
              newt = (t < absolute_max_time - SECSPERDAY / 2
                  ? t + SECSPERDAY / 2
                  : absolute_max_time);
              if (cuthitime <= newt)
!                 newt = cuthitime;
              newtmp = localtime_rz(tz, &newt, &newtm);
              if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
                  (delta(&newtm, &tm) != (newt - t) ||



On Sat, Sep 6, 2014 at 6:54 PM, Tim Parenti <tim at timtimeonline.com> wrote:

>  While sorting out some issues for tzdist, I noticed a bug in zdump,
> which is still present in 2014g.
>
>  Running zdump on Asia/Singapore for both 1981 and 1982 together produces
> the expected transition from UTC+7:30 to UTC+8 at the boundary between
> those years:
>
> $ ./zdump.exe -vc 1981,1983 Asia/Singapore
> Asia/Singapore  -9223372036854775808 = NULL
> Asia/Singapore  -9223372036854689408 = NULL
> Asia/Singapore  Thu Dec 31 16:29:59 1981 UT = Thu Dec 31 23:59:59 1981 SGT
> isdst=0
> Asia/Singapore  Thu Dec 31 16:30:00 1981 UT = Fri Jan  1 00:30:00 1982 SGT
> isdst=0
> Asia/Singapore  9223372036854689407 = NULL
> Asia/Singapore  9223372036854775807 = NULL
>
>  However, running it on 1981 and 1982 individually does not:
>
> $ ./zdump.exe -vc 1981,1982 Asia/Singapore
> Asia/Singapore  -9223372036854775808 = NULL
> Asia/Singapore  -9223372036854689408 = NULL
> Asia/Singapore  9223372036854689407 = NULL
> Asia/Singapore  9223372036854775807 = NULL
>
> $ ./zdump.exe -vc 1982,1983 Asia/Singapore
> Asia/Singapore  -9223372036854775808 = NULL
> Asia/Singapore  -9223372036854689408 = NULL
> Asia/Singapore  9223372036854689407 = NULL
> Asia/Singapore  9223372036854775807 = NULL
>
>  Initially, I thought this might have to do with the fact that the
> transition is specified as a Zone continuation line rather than as a Rule,
> since zdump properly handled my extended edge-case examples to Jon Skeet a
> while back:
> http://mm.icann.org/pipermail/tz/2014-July/021162.html
>
>  zdump also properly handles Asia/Dhaka's DST transition at the end of
> 2009, but fails in some other similar cases.
>
>  So it looks like it's more to do with the transition taking place too
> close to the year boundary.  Part of the problem may be the transition
> happening in different years, UTC and local, but that doesn't seem to be
> all that's going on.
>
> Attached are some test cases to run against various versions of Singapore
> with 1981,1982 and 1982,1983; and various versions of Dhaka with 2009,2010
> and 2010,2011.  All of these should work, but most currently don't.  (The
> ones that do are marked.)
>
> --
> Tim Parenti
>
>
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1.1
927 lines
1.2
927 lines
*** /tmp/,azdump.c	2014-09-06 19:56:41.335772400 -0400
--- /tmp/,bzdump.c	2014-09-06 19:56:41.423777400 -0400
***************
*** 654,665 ****
  		tmp = my_localtime_rz(tz, &t, &tm);
  		if (tmp)
  		  ab = saveabbr(&abbrev, &abbrevsize, &tm);
! 		for ( ; ; ) {
  			newt = (t < absolute_max_time - SECSPERDAY / 2
  				? t + SECSPERDAY / 2
  				: absolute_max_time);
  			if (cuthitime <= newt)
! 				break;
  			newtmp = localtime_rz(tz, &newt, &newtm);
  			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
  				(delta(&newtm, &tm) != (newt - t) ||
--- 654,665 ----
  		tmp = my_localtime_rz(tz, &t, &tm);
  		if (tmp)
  		  ab = saveabbr(&abbrev, &abbrevsize, &tm);
! 		while (t < cuthitime) {
  			newt = (t < absolute_max_time - SECSPERDAY / 2
  				? t + SECSPERDAY / 2
  				: absolute_max_time);
  			if (cuthitime <= newt)
! 				newt = cuthitime;
  			newtmp = localtime_rz(tz, &newt, &newtm);
  			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
  				(delta(&newtm, &tm) != (newt - t) ||