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Bugfix: Use Locale.ROOT for ISO8601 date formatting to prevent localized digits #126

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Merged
marcprux merged 1 commit into from
Jul 17, 2026
Merged

Bugfix: Use Locale.ROOT for ISO8601 date formatting to prevent localized digits #126

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4 changes: 1 addition & 3 deletions Sources/SkipFoundation/Date.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -181,9 +181,7 @@ public struct Date : Hashable, CustomStringConvertible, Comparable, Codable, Kot

public func ISO8601Format(_ style: Date.ISO8601FormatStyle = .iso8601) -> String {
// TODO: use the style parameters
// local time zone specific
// return java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX", java.util.Locale.getDefault()).format(platformValue)
var dateFormat = java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", java.util.Locale.getDefault())
var dateFormat = java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", java.util.Locale.ROOT)
dateFormat.timeZone = java.util.TimeZone.getTimeZone("GMT")
return dateFormat.format(platformValue)
}
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20 changes: 20 additions & 0 deletions Tests/SkipFoundationTests/Foundation/DateTests.swift
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Expand Up @@ -49,6 +49,26 @@ final class DateTests: XCTestCase {
XCTAssertEqual("4001-01-01T00:00:00Z", Date.distantFuture.ISO8601Format())
}

func testISO8601FormattingIsLocaleIndependent() throws {
let date = Date(timeIntervalSince1970: 1_783_042_560)

#if SKIP
// Simulates a device configured with Eastern Arabic numerals (0-9 -> ٠-٩).
// This replicates the OS-level system settings that would distort technical
// string formatting when relying on `Locale.getDefault()`.
let originalLocale = java.util.Locale.getDefault()
let arabicNumbersLocale = java.util.Locale.Builder()
.setLanguage("ar")
.setExtension(java.util.Locale.UNICODE_LOCALE_EXTENSION, "nu-arab")
.build()

java.util.Locale.setDefault(arabicNumbersLocale)
defer { java.util.Locale.setDefault(originalLocale) }
#endif

XCTAssertEqual("2026-07-03T01:36:00Z", date.ISO8601Format())
}

func testDateFormatting() throws {
func fmt(_ format: String, _ date: Date) -> String {
let fmt = DateFormatter()
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