https://github.com/llvmbot created
https://github.com/llvm/llvm-project/pull/127531
Backport 941f7cbf5a3e7aa9f36b002dc22cfdb4ff50fea8
Requested by: @mordante
>From 2b96bbb64e0de22f9ac41aca6a3249cfbe8e8fa0 Mon Sep 17 00:00:00 2001
From: Mark de Wever <ko...@xs4all.nl>
Date: Mon, 17 Feb 2025 19:08:07 +0100
Subject: [PATCH] [libc++][TZDB] Fixes mapping of nonexisting time. (#127330)
All non-existing local times in a contiguous range should map to the
same time point. This fixes a bug, were the times inside the range were
mapped to the wrong time.
Fixes: #113654
(cherry picked from commit 941f7cbf5a3e7aa9f36b002dc22cfdb4ff50fea8)
---
libcxx/include/__chrono/time_zone.h | 8 ++++++--
.../time.zone.members/to_sys_choose.pass.cpp | 17 +++++++++++++++--
2 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/libcxx/include/__chrono/time_zone.h
b/libcxx/include/__chrono/time_zone.h
index ab5c22eceaaf1..d18d59d2736bf 100644
--- a/libcxx/include/__chrono/time_zone.h
+++ b/libcxx/include/__chrono/time_zone.h
@@ -103,10 +103,14 @@ class _LIBCPP_AVAILABILITY_TZDB time_zone {
to_sys(const local_time<_Duration>& __time, choose __z) const {
local_info __info = get_info(__time);
switch (__info.result) {
- case local_info::unique:
- case local_info::nonexistent: // first and second are the same
+ case local_info::unique: // first and second are the same
return sys_time<common_type_t<_Duration,
seconds>>{__time.time_since_epoch() - __info.first.offset};
+ case local_info::nonexistent:
+ // first and second are the same
+ // All non-existing values are converted to the same time.
+ return sys_time<common_type_t<_Duration, seconds>>{__info.first.end};
+
case local_info::ambiguous:
switch (__z) {
case choose::earliest:
diff --git
a/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/to_sys_choose.pass.cpp
b/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/to_sys_choose.pass.cpp
index bad4ef352e9b9..1147c9fadf9ae 100644
---
a/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/to_sys_choose.pass.cpp
+++
b/libcxx/test/std/time/time.zone/time.zone.timezone/time.zone.members/to_sys_choose.pass.cpp
@@ -88,7 +88,7 @@ static void test_nonexistent() {
// Pick an historic date where it's well known what the time zone rules were.
// This makes it unlikely updates to the database change these rules.
std::chrono::local_time<std::chrono::seconds> time{
- (std::chrono::sys_days{std::chrono::March / 30 / 1986} + 2h +
30min).time_since_epoch()};
+ (std::chrono::sys_days{std::chrono::March / 30 / 1986} +
2h).time_since_epoch()};
std::chrono::sys_seconds expected{time.time_since_epoch() - 1h};
@@ -100,6 +100,13 @@ static void test_nonexistent() {
assert(tz->to_sys(time + 0us, std::chrono::choose::latest) == expected);
assert(tz->to_sys(time + 0ms, std::chrono::choose::earliest) == expected);
assert(tz->to_sys(time + 0s, std::chrono::choose::latest) == expected);
+
+ // The entire nonexisting hour should map to the same time.
+ // For nonexistant the value of std::chrono::choose has no effect.
+ assert(tz->to_sys(time + 1s, std::chrono::choose::earliest) == expected);
+ assert(tz->to_sys(time + 1min, std::chrono::choose::latest) == expected);
+ assert(tz->to_sys(time + 30min, std::chrono::choose::earliest) == expected);
+ assert(tz->to_sys(time + 59min + 59s, std::chrono::choose::latest) ==
expected);
}
// Tests ambiguous conversions.
@@ -120,7 +127,7 @@ static void test_ambiguous() {
// Pick an historic date where it's well known what the time zone rules were.
// This makes it unlikely updates to the database change these rules.
std::chrono::local_time<std::chrono::seconds> time{
- (std::chrono::sys_days{std::chrono::September / 28 / 1986} + 2h +
30min).time_since_epoch()};
+ (std::chrono::sys_days{std::chrono::September / 28 / 1986} +
2h).time_since_epoch()};
std::chrono::sys_seconds earlier{time.time_since_epoch() - 2h};
std::chrono::sys_seconds later{time.time_since_epoch() - 1h};
@@ -133,6 +140,12 @@ static void test_ambiguous() {
assert(tz->to_sys(time + 0us, std::chrono::choose::latest) == later);
assert(tz->to_sys(time + 0ms, std::chrono::choose::earliest) == earlier);
assert(tz->to_sys(time + 0s, std::chrono::choose::latest) == later);
+
+ // Test times in the ambigious hour
+ assert(tz->to_sys(time + 1s, std::chrono::choose::earliest) == earlier + 1s);
+ assert(tz->to_sys(time + 1min, std::chrono::choose::latest) == later + 1min);
+ assert(tz->to_sys(time + 30min, std::chrono::choose::earliest) == earlier +
30min);
+ assert(tz->to_sys(time + 59min + 59s, std::chrono::choose::latest) == later
+ 59min + 59s);
}
// This test does the basic validations of this function. The library function
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