diff options
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 99 |
1 files changed, 98 insertions, 1 deletions
@@ -1,5 +1,100 @@ News for the tz database +Release 2026a - 2026-03-01 22:59:49 -0800 + + Briefly: + Moldova has used EU transition times since 2022. + The "right" TZif files are no longer installed by default. + -DTZ_RUNTIME_LEAPS=0 disables runtime support for leap seconds. + TZif files are no longer limited to 50 bytes of abbreviations. + zic is no longer limited to 50 leap seconds. + Several integer overflow bugs have been fixed. + + Changes to past and future timestamps + + Since 2022 Moldova has observed EU transition times, that is, it + has sprung forward at 03:00, not 02:00, and has fallen back at + 04:00, not 03:00. (Thanks to Heitor David Pinto.) + + Changes to data + + Remove Europe/Chisinau from zonenow.tab, as it now agrees with + Europe/Athens for future timestamps. + + Changes to build procedure + + The Makefile no longer by default installs an alternate set + of TZif files for system clocks that count leap seconds. + Install with 'make REDO=posix_right' to get the old default, + which is rarely used in major downstream distributions. + If your system clock counts leap seconds (contrary to POSIX), + it is better to install with 'make REDO=right_only'. + This change does not affect the leapseconds file, which is still + installed as before. + + The Makefile's POSIXRULES option, which was declared obsolete in + release 2019b, has been removed. The Makefile's build procedure + thus no longer optionally installs the obsolete posixrules file. + + Changes to code + + Compiling with the new option -DTZ_RUNTIME_LEAPS=0 disables + runtime support for leap seconds. Although this conforms to + POSIX, shrinks tzcode's attack surface, and is more efficient, + it fails to support Internet RFC 9636's leap seconds. + + zic now can generate, and localtime.c can now use, TZif files that + hold up to 256 bytes of abbreviations, counting trailing NULs. + The previous limit was 50 bytes, and some tzdata TZif files were + already consuming 40 bytes. zic -v warns if it generates a file + that exceeds the old 50-byte limit. + + zic -L can now generate TZif files with more than 50 leap seconds. + This helps test TZif readers not limited to 50 leap seconds, as + tzcode's localtime.c is; it has little immediate need for + practical timekeeping as there have been only 27 leap seconds and + possibly there will be no more, due to planned changes to UTC. + zic -v warns if its output exceeds the old 50-second limit. + + localtime.c no longer accesses the posixrules file generated by + zic -p. Hence for obsolete and nonconforming settings like + TZ="AST4ADT" it now typically falls back on US DST rules, rather + than attempting to override this fallback with the contents of the + posixrules file. This removes library support that was declared + obsolete in release 2019b, and fixes some undefined behavior. + (Undefined behavior reported by GitHub user Naveed8951.) + + The posix2time, posix2time_z, time2posix, and time2posix_z + functions now set errno=EOVERFLOW and return ((time_t) -1) if the + result is not representable. Formerly they had undefined behavior + that could in practice result in crashing, looping indefinitely, + or returning an incorrect result. As before, these functions are + defined only when localtime.c is compiled with the -DSTD_INSPIRED + option. + + Some other undefined behavior, triggered by TZif files containing + outlandish but conforming UT offsets or leap second corrections, + has also been fixed. (Some of these bugs reported by Naveed8951.) + + localtime.c no longer rejects TZif files that exactly fit in its + internal structures, fixing off-by-one typos introduced in 2014g. + + zic no longer generates a no-op transition when + simultaneous Rule and Zone changes cancel each other out. + This occurs in tzdata only in Asia/Tbilisi on 1997-03-30. + (Thanks to Renchunhui for a test case showing the bug.) + + zic no longer assumes you can fflush a read-only stream. + (Problem reported by Christos Zoulas.) + + zic no longer generates UT offsets equal to -2**31 and localtime.c + no longer accepts them, as they can cause trouble in both + localtime.c and its callers. RFC 9636 prohibits such offsets. + + zic -p now warns that the -p option is obsolete and likely + ineffective. + + Release 2025c - 2025-12-10 14:42:37 -0800 Briefly: @@ -69,6 +164,8 @@ Release 2025c - 2025-12-10 14:42:37 -0800 The new CFLAGS options -DHAVE_STRUCT_STAT_ST_CTIM=0 and -DHAVE_STRUCT_TIMESPEC=0 port to non-POSIX.1-2008 platforms that lack st_ctim and struct timespec, respectively. + On these platforms, the code falls back on st_ctime to + implement -DTZ_CHANGE_INTERVAL=N. tzset etc. now treat ' ' like '_' in time zone abbreviations, just as they treat other invalid bytes. This continues the @@ -89,7 +186,7 @@ Release 2025c - 2025-12-10 14:42:37 -0800 The new CFLAGS option -TTHREAD_TM_MULTI causes localtime to return a pointer to thread-specific memory, as FreeBSD does, instead of - to the same memory in all threads. This supports unportable + to the same memory in all threads. This supports nonportable programs that incorrectly use localtime instead of localtime_r. This option affects gmtime and offtime similarly to localtime. Because the corresponding storage is freed on thread exit, this |