MDEV-38029 my_tzinfo-t fails for certain TZ values on musl #4452
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Pull Request Overview
This PR fixes test failures in my_tzinfo-t on musl-based Linux distributions (such as Alpine) by working around a musl libc bug that incorrectly calculates DST transitions for certain timezone values.
- Adds conditional skipping of 6 timezone offset/abbreviation tests when musl is detected and specific problematic TZ values are used
- Skips tests for
PST8PDTandGST-1GDTtimezones which exhibit the bug on musl
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unittest/mysys/my_tzinfo-t.c
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| #if defined __linux__ && !defined __GLIBC__ && !defined __UCLIBC__ | ||
| /* | ||
| MUSL incorrectly calculates UTC offsets and abbreviations | ||
| for certain values of TZ (DST related).See MDEV-38029 |
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Missing space after period. Should be "TZ (DST related). See MDEV-38029" instead of "TZ (DST related).See MDEV-38029".
Suggested change
| for certain values of TZ (DST related).See MDEV-38029 | |
| for certain values of TZ (DST related). See MDEV-38029 |
The test fails for TZ values such as `PST8PDT` (present but outdated in tzdb) and custom forms like `GST-1GDT`. On musl, these values do not trigger the expected DST transitions, leading to incorrect DST offsets or abbreviations. This appears to be a musl libc bug; the same TZ values behave correctly elsewhere, including Windows. We work around it by skipping the affected tests when musl is detected.
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For what my comment's worth, this patch works for me, thanks a lot. |
grooverdan
approved these changes
Nov 20, 2025
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Description
The test fails for TZ values such as
PST8PDT(present but outdated in tzdb) and custom forms likeGST-1GDT. On musl, these values do not trigger the expected DST transitions, leading to incorrect DST offsets or abbreviations.This appears to be a musl libc bug; the same TZ values behave correctly elsewhere, including Windows. We work around it by skipping the affected tests when musl is detected.
Release Notes
Fixed unittest my_tzinfo-t to pass on musl based Linux distributions such as Alpine
How can this PR be tested?
Run the test on affected distro, like I did
desktop:~/xxx$ ./unittest/mysys/my_tzinfo-t
1..38
ok 1 # skip no test for default timezone name UTC
ok 2 - GMT offset is whole number of minutes 0
ok 3 - UTC: Offset for timestamp 1690000000 is 0/0
ok 4 - tz abbreviation UTC
ok 5 - GMT offset is whole number of minutes 0
ok 6 - UTC: Offset for timestamp 1700000000 is 0/0
ok 7 - tz abbreviation UTC
ok 8 - GMT offset is whole number of minutes 0
ok 9 - UTC: Offset for timestamp 1763552561 is 0/0
ok 10 - tz abbreviation UTC
ok 11 - PST8PDT: timezone_name = PDT
ok 12 # skip musl UTC offset/abbreviation bug, tzname PST8PDT, see MDEV-38029
ok 13 # skip musl UTC offset/abbreviation bug, tzname PST8PDT, see MDEV-38029
ok 14 # skip musl UTC offset/abbreviation bug, tzname PST8PDT, see MDEV-38029
ok 15 # skip musl UTC offset/abbreviation bug, tzname PST8PDT, see MDEV-38029
ok 16 # skip musl UTC offset/abbreviation bug, tzname PST8PDT, see MDEV-38029
ok 17 # skip musl UTC offset/abbreviation bug, tzname PST8PDT, see MDEV-38029
ok 18 - GMT: timezone_name = GMT
ok 19 - GMT: Summer GMT offset 0
ok 20 - GMT: Offset for timestamp 1690000000 is 0/0
ok 21 - GMT: Summer time abbreviation GMT
ok 22 - GMT: Winter GMT offset 0
ok 23 - GMT: Offset for timestamp 1700000000 is 0/0
ok 24 - GMT: Winter time abbreviation GMT
ok 25 - GST-1GDT: timezone_name = GDT
ok 26 # skip musl UTC offset/abbreviation bug, tzname GST-1GDT, see MDEV-38029
ok 27 # skip musl UTC offset/abbreviation bug, tzname GST-1GDT, see MDEV-38029
ok 28 # skip musl UTC offset/abbreviation bug, tzname GST-1GDT, see MDEV-38029
ok 29 # skip musl UTC offset/abbreviation bug, tzname GST-1GDT, see MDEV-38029
ok 30 # skip musl UTC offset/abbreviation bug, tzname GST-1GDT, see MDEV-38029
ok 31 # skip musl UTC offset/abbreviation bug, tzname GST-1GDT, see MDEV-38029
ok 32 - IST-5:30: timezone_name = IST
ok 33 - IST-5:30: Summer GMT offset 19800
ok 34 - IST-5:30: Offset for timestamp 1690000000 is 19800/19800
ok 35 - IST-5:30: Summer time abbreviation IST
ok 36 - IST-5:30: Winter GMT offset 19800
ok 37 - IST-5:30: Offset for timestamp 1700000000 is 19800/19800
ok 38 - IST-5:30: Winter time abbreviation IST
Test took 0.00 sec
If the changes are not amenable to automated testing, please explain why not and carefully describe how to test manually.
Basing the PR against the correct MariaDB version
mainbranch.PR quality check