tzdb 2026b: การเปลี่ยนเขตเวลา 1 รายการ

Changes to code

• zic no longer mishandles a last transition to a new time type. NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA: This zic fix is needed for the temporary hack (mentioned above) that works around the Canadian timekeeping bug in Unicode CLDR. Without the fix, the temporary hack causes zic versions 2023d through 2026a, in their default mode that generates slim output, to generate a TZif file that violates Internet RFC 9636 §3.3. The buggy file in turn causes some TZif readers, including tzcode itself, to ignore America/Vancouver’s 2026-11-01 02:00 transition from PDT (tm_isdst=1) to MST (tm_isdst=0). Although the buggy file does not cause any known TZif reader to mishandle UT offsets, caution is advised when using zic 2023d through 2026a to compile data from more-recent tz releases. To work around this problem when using these older zic versions, use ‘zic -b fat’.
• zic no longer overflows a buffer when generating a TZ string like "PST-167:59:58PDT-167:59:59,M11.5.6/-167:59:59,M12.5.6/-167:59:59", which can occur with adversarial input. (Thanks to Naveed Khan.)
• zic no longer generates a longer TZif file than necessary when an earlier time zone abbreviation is a suffix of a later one. As a nice side effect, zic no longer overflows a buffer when given a long series of abbreviations, each a suffix of the next. (Buffer overflow reported by Arthur Chan.)
• zic no longer overflows an int when processing input like ‘Zone Ouch 2147483648:00:00 - LMT’. The int overflow can lead to buffer overflow in adversarial cases. (Thanks to Naveed Khan.)
• zic now checks for signals more often.