Landing: 57a09e2f362a
Project / Subsystem
gcc / libstdc++
Date
2026-07-17
Author
Tomasz Kamiński
Commit
57a09e2f362ab8a8be84250fd4266b333a74b977
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- libstdc++
- patch_id
- —
- commit_hash
- 57a09e2f362ab8a8be84250fd4266b333a74b977
- source_type
- github
- headline
- libstdc++: Fix condition for stopping lazy zone expansion
- tldr
- Corrects zone expansion logic in C++20 timezone database to handle DST transitions accurately.
- author
- Tomasz Kamiński
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • libstdc++
- • time zone
- • c++20
- • bugfix
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-17T00:00:00.000Z
The C++20 timezone database’s lazy zone expansion logic has been corrected. Previously, it incorrectly assumed expansion could only resume from a standard time (STD) zone. This patch modifies the condition to properly handle transitions between daylight saving time (DST) zones, ensuring more accurate time zone data handling. A test case for a specific historical transition in the America/Dawson timezone is included.