[tz] [PROPOSED] zic option for including data from a certain year onward

[Christopher Wong]

I rebased to the latest and did some testing. I didn't got any more segmentation fault, so that is fixed.

However, I encountered something else related to the truncation. I compiled with the following range 1977-1984 :

./zic -L /dev/null   -d $ZONEINFO  -r @220924800/@441763200  ${tz}

./zdump -v $ZONEINFO/Australia/Perth

The result I got was:

/home/christwo/dists/tz/test_zic_github/Australia/Perth  -9223372036854775808 = NULL
/home/christwo/dists/tz/test_zic_github/Australia/Perth  -9223372036854689408 = NULL
/home/christwo/dists/tz/test_zic_github/Australia/Perth  Sat Oct 29 17:59:59 1983 UT = Sun Oct 30 01:59:59 1983 AWST isdst=0 gmtoff=28800
/home/christwo/dists/tz/test_zic_github/Australia/Perth  Sat Oct 29 18:00:00 1983 UT = Sun Oct 30 03:00:00 1983 AWDT isdst=1 gmtoff=32400
/home/christwo/dists/tz/test_zic_github/Australia/Perth  9223372036854689407 = NULL
/home/christwo/dists/tz/test_zic_github/Australia/Perth  9223372036854775807 = NULL

I was expecting many dates before 1983. 

I made a hexdump from the Australia/Perth TZif file:

00000000  54 5a 69 66 32 00 00 00  00 00 00 00 00 00 00 00  |TZif2...........|
00000010  00 00 00 00 00 00 00 02  00 00 00 02 00 00 00 00  |................|
00000020  00 00 00 03 00 00 00 02  00 00 00 0a 0d 2b 0b 80  |.............+..|
00000030  1a 01 62 a0 1a 54 c5 81  00 01 01 00 00 70 80 00  |..b..T.......p..|
00000040  00 00 00 7e 90 01 05 41  57 53 54 00 41 57 44 54  |...~...AWST.AWDT|
00000050  00 01 01 00 00 54 5a 69  66 32 00 00 00 00 00 00  |.....TZif2......|
00000060  00 00 00 00 00 00 00 00  00 00 00 00 02 00 00 00  |................|
00000070  02 00 00 00 00 00 00 00  03 00 00 00 02 00 00 00  |................|
00000080  0a 00 00 00 00 0d 2b 0b  80 00 00 00 00 1a 01 62  |......+........b|
00000090  a0 00 00 00 00 1a 54 c5  81 00 01 01 00 00 70 80  |......T.......p.|
000000a0  00 00 00 00 7e 90 01 05  41 57 53 54 00 41 57 44  |....~...AWST.AWD|
000000b0  54 00 01 01 00 00 0a 0a                           |T.......|
000000b8

>From it I extracted the timestamps below, should the last transition be 1s after range end?

0d 2b 0b 80     220924800	Saturday, January 1, 1977 0:00:00 
1a 01 62 a0	    436298400	Saturday, October 29, 1983 18:00:00 
1a 54 c5 81	    441763201	Sunday, January 1, 1984 0:00:01 

According to RFC 8536:

   When truncating the end of a TZif file, the service MUST supply in
   the version 2+ data a last transition time that is the end point of
   the truncation range

I was kind of expecting the last transition to be within my supplied range or am I misinterpreting the RFC?

BR,
Christopher Wong

________________________________________
From: Paul Eggert <eggert at cs.ucla.edu>
Sent: Thursday, March 14, 2019 17:30
To: Christopher Wong
Cc: Scott Nelson; Time Zone Mailing List
Subject: Re: [tz] [PROPOSED] zic option for including data from a certain year onward

On 3/12/19 5:01 AM, Christopher Wong wrote:
> If I do:
> make clean
> make ... install
> as you specified, then I don't see the segmentation faults either. I guess, I just didn't do it the right way.

No, your approach should have worked, even though -y is obsolescent and
your use of it had no effect and we should remove -y one of these days.
I installed the attached patch to fix the bug that you found. Thanks for
reporting it.