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Fix crashes caused by a race condition in icu::OlsonTimeZone::initTransitionRules #1597

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Merged
merged 1 commit into from
Nov 14, 2025
Merged

Fix crashes caused by a race condition in icu::OlsonTimeZone::initTransitionRules #1597

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84 changes: 51 additions & 33 deletions Sources/FoundationInternationalization/TimeZone/TimeZone_ICU.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@ internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
}

// This is safe because it's only mutated at deinit time
nonisolated(unsafe) private let _timeZone : UnsafePointer<UTimeZone?>
nonisolated(unsafe) private let _timeZone : LockedState<UnsafePointer<UTimeZone?>>

// This type is safely sendable because it is guarded by a lock in _TimeZoneICU and we never vend it outside of the lock so it can only ever be accessed from within the lock
struct State : @unchecked Sendable {
Expand Down Expand Up @@ -86,8 +86,10 @@ internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
ucal_close(c)
}

let mutableT = UnsafeMutablePointer(mutating: _timeZone)
uatimezone_close(mutableT)
_timeZone.withLock {
let mutableT = UnsafeMutablePointer(mutating: $0)
uatimezone_close(mutableT)
}
}

required init?(identifier: String) {
Expand Down Expand Up @@ -117,8 +119,7 @@ internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
guard let timeZone else {
return nil
}

self._timeZone = UnsafePointer(timeZone)
self._timeZone = .init(initialState:timeZone)
self.name = name
lock = LockedState(initialState: State())
}
Expand All @@ -133,15 +134,16 @@ internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
}

func secondsFromGMT(for date: Date) -> Int {
var rawOffset: Int32 = 0
var dstOffset: Int32 = 0
var status: UErrorCode = U_ZERO_ERROR
uatimezone_getOffset(_timeZone, date.udate, 0, &rawOffset, &dstOffset, &status)
guard status.checkSuccessAndLogError("error getting uatimezone offset") else {
return 0
return _timeZone.withLock {
var rawOffset: Int32 = 0
var dstOffset: Int32 = 0
var status: UErrorCode = U_ZERO_ERROR
uatimezone_getOffset($0, date.udate, 0, &rawOffset, &dstOffset, &status)
guard status.checkSuccessAndLogError("error getting uatimezone offset") else {
return 0
}
return Int((rawOffset + dstOffset) / 1000)
}

return Int((rawOffset + dstOffset) / 1000)
}

func abbreviation(for date: Date) -> String? {
Expand All @@ -157,33 +159,38 @@ internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
}

func daylightSavingTimeOffset(for date: Date) -> TimeInterval {
var rawOffset_unused: Int32 = 0
var dstOffset: Int32 = 0
var status = U_ZERO_ERROR
uatimezone_getOffset(_timeZone, date.udate, 0, &rawOffset_unused, &dstOffset, &status)
if status.isSuccess {
_timeZone.withLock {
var rawOffset_unused: Int32 = 0
var dstOffset: Int32 = 0
var status = U_ZERO_ERROR
uatimezone_getOffset($0, date.udate, 0, &rawOffset_unused, &dstOffset, &status)
guard status.isSuccess else {
return 0.0
}
return TimeInterval(Double(dstOffset) / 1000.0)
} else {
return 0.0
}
}

func nextDaylightSavingTimeTransition(after date: Date) -> Date? {
var status = U_ZERO_ERROR
var answer = UDate(0.0)
let success = uatimezone_getTimeZoneTransitionDate(_timeZone, date.udate, UCAL_TZ_TRANSITION_NEXT, &answer, &status)
let limit = Date.validCalendarRange.upperBound
let answer: UDate? = _timeZone.withLock {
var status = U_ZERO_ERROR
var answer = UDate(0.0)
let success = uatimezone_getTimeZoneTransitionDate($0, date.udate, UCAL_TZ_TRANSITION_NEXT, &answer, &status)
guard (success != 0) && status.isSuccess && answer < limit.udate else {
return nil
}
return answer
}

let limit = Date.validCalendarRange.upperBound
guard (success != 0) && status.isSuccess && answer < limit.udate else {
return nil
}
return Date(udate: answer)
}
guard let answer else {
return nil
}

return Date(udate: answer)
}

func rawAndDaylightSavingTimeOffset(for date: Date, repeatedTimePolicy: TimeZone.DaylightSavingTimePolicy = .former, skippedTimePolicy: TimeZone.DaylightSavingTimePolicy = .former) -> (rawOffset: Int, daylightSavingOffset: TimeInterval) {
var rawOffset: Int32 = 0
var dstOffset: Int32 = 0
var status = U_ZERO_ERROR
let icuDuplicatedTime: UTimeZoneLocalOption
switch repeatedTimePolicy {
case .former:
Expand All @@ -200,7 +207,18 @@ internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
icuSkippedTime = UCAL_TZ_LOCAL_LATTER
}

uatimezone_getOffsetFromLocal(_timeZone, icuSkippedTime, icuDuplicatedTime, date.udate, &rawOffset, &dstOffset, &status)
let (rawOffset, dstOffset): (Int32, Int32) = _timeZone.withLock {
var rawOffset: Int32 = 0
var dstOffset: Int32 = 0
var status = U_ZERO_ERROR
uatimezone_getOffsetFromLocal($0, icuSkippedTime, icuDuplicatedTime, date.udate, &rawOffset, &dstOffset, &status)

guard status.isSuccess else {
return (0, 0)
}
return (rawOffset, dstOffset)
}

return (Int(rawOffset / 1000), TimeInterval(dstOffset / 1000))
}

Expand Down