On Fri, 26 Aug 2022 18:56:31 GMT, Naoto Sato <na...@openjdk.org> wrote:
>> After `test/jdk/java/util/TimeZone/CustomTzIDCheckDST.java` testcase was >> integrated, it failed on the AIX platform. >> >> Error output >> >> STDERR: >> stdout: []; >> stderr: [Exception in thread "main" java.lang.RuntimeException: Got >> unexpected timezone information: Thu Aug 25 09:29:10 CEST 2022 >> at CustomTzIDCheckDST.runTZTest(CustomTzIDCheckDST.java:71) >> at CustomTzIDCheckDST.main(CustomTzIDCheckDST.java:50) >> ] >> >> >> By my investigation, `TZ=MEZ-1MESZ,M3.5.0,M10.5.0` timezone was changed to >> `Europe/Berlin` timezone on AIX platform. >> It seems this situation is happened because older AIX did not support >> `MEZ-1MESZ,M3.5.0,M10.5.0` timezone by TZ environment variable. >> https://www.ibm.com/support/pages/managing-time-zone-variable-posix >> AIX special code was implemented into >> `src/java.base/unix/native/libjava/TimeZone_md.c`. >> Current AIX supports `TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00` style. >> I think implementation change is required. >> >> Some pre-submit tests are failed, but I think these are not related this >> change since modified parts are just for AIX platform. > > src/java.base/unix/native/libjava/TimeZone_md.c line 589: > >> 587: // But Hotspot does not support XPG_SUS_ENV=ON. >> 588: // Ignore daylight saving settings to calculate current time >> difference >> 589: localtm.tm_isdst = 0; > > Is it OK to reset it always? Could this defy the original purpose of the fix > to https://bugs.openjdk.org/browse/JDK-8285838? I executed test program [JDK-8285838](https://bugs.openjdk.org/browse/JDK-8285838) on RHEL8 x86_64. TZ="MEZ-1MESZ,M3.5.0,M10.5.0" means I'm on daylight saving time on today. By JDK18 $ TZ="MEZ-1MESZ,M3.5.0,M10.5.0" jdk-18/bin/java -showversion TimeTest.java openjdk version "18" 2022-03-22 OpenJDK Runtime Environment (build 18+36-2087) OpenJDK 64-Bit Server VM (build 18+36-2087, mixed mode, sharing) Calendar.getInstance().getTime() = Thu Sep 01 11:52:09 GMT+01:00 2022 SimpleDateFormat = 01.09.2022 11:52:09.747 By JDK20 $ TZ="MEZ-1MESZ,M3.5.0,M10.5.0" jdk-20-b12/bin/java -showversion TimeTest.java openjdk version "20-ea" 2023-03-21 OpenJDK Runtime Environment (build 20-ea+12-790) OpenJDK 64-Bit Server VM (build 20-ea+12-790, mixed mode, sharing) Calendar.getInstance().getTime() = Thu Sep 01 12:52:21 GMT+02:00 2022 SimpleDateFormat = 01.09.2022 12:52:21.269 Expected result is GMT+02:00. It means the output is the current time difference between GMT and MESZ. On modified build $ TZ="MEZ-1MESZ,M3.5.0,M10.5.0" jdk/build/aix-ppc64-server-release/images/jdk/bin/java TimeTest.java Calendar.getInstance().getTime() = Thu Sep 01 12:53:12 GMT+02:00 2022 SimpleDateFormat = 01.09.2022 12:53:12.930 According to AIX docs for mktime() https://www.ibm.com/docs/en/aix/7.2?topic=c-ctime-localtime-gmtime-mktime-difftime-asctime-tzset-subroutine > The value of the ```tm_isdst``` field determines the following actions of the > **mktime** subroutine: > "0" means "Initially presumes that Daylight Saving Time (DST) is not in > effect." If daylight saving time ends by August, timezone should be GMT+01:00 $ TZ="MEZ-1MESZ,M3.5.0,M8.5.0" jdk/build/aix-ppc64-server-release/images/jdk/bin/java TimeTest.java Calendar.getInstance().getTime() = Thu Sep 01 11:53:36 GMT+01:00 2022 SimpleDateFormat = 01.09.2022 11:53:36.189 According to simple C testcase $ cat sf.c #include <stdio.h> #include <stdlib.h> #include <time.h> int main(void) { char buf[100]; struct tm localtm; struct tm gmt; time_t clock = time(NULL); int gmt_off; #if defined(_AIX) putenv("XPG_SUS_ENV=ON"); #endif if (localtime_r(&clock, &localtm) == NULL) { return 1; } if (gmtime_r(&clock, &gmt) == NULL) { return 1; } strftime(buf, sizeof(buf),"%z", &localtm); printf("strftime: %s\n",buf); localtm.tm_isdst = 0; gmt_off = (int)(difftime(mktime(&localtm), mktime(&gmt)) / 60.0); sprintf(buf, (const char *)"%c%02.2d%02.2d", gmt_off < 0 ? '-' : '+' , abs(gmt_off / 60), gmt_off % 60); printf("difftime: %s\n",buf); return 0; } On RHEL8: $ TZ="MEZ-1MESZ,M3.5.0,M10.5.0" ./sf strftime: +0200 difftime: +0200 $ TZ="ZZZ-1ZZZZ-3,M3.5.0,M10.5.0" ./sf strftime: +0300 difftime: +0300 $ TZ="ZZZ-1ZZZZ-3,M3.5.0,M8.5.0" ./sf strftime: +0100 difftime: +0100 On AIX: $ TZ="MEZ-1MESZ,M3.5.0,M10.5.0" ./sf strftime: +0200 difftime: +0200 $ TZ="ZZZ-1ZZZZ-3,M3.5.0,M10.5.0" ./sf strftime: +0300 difftime: +0300 $ TZ="ZZZ-1ZZZZ-3,M3.5.0,M8.5.0" ./sf strftime: +0100 difftime: +0100 I assume the modified code should be fine. ------------- PR: https://git.openjdk.org/jdk/pull/10036
