Fix DateFormatter TimeZone Setter

CoreFoundation/NumberDate.subproj/CFTimeZone.c

@@ -793,7 +793,7 @@ static CFTimeZoneRef __CFTimeZoneCreateSystem(void) {
         size_t zoneInfoDirLen = CFStringGetLength(__tzZoneInfo);
         if (strncmp(linkbuf, tzZoneInfo, zoneInfoDirLen) == 0) {
             name = CFStringCreateWithBytes(kCFAllocatorSystemDefault, (uint8_t *)linkbuf + zoneInfoDirLen,
-                                           strlen(linkbuf) - zoneInfoDirLen + 1, kCFStringEncodingUTF8, false);
+                                           strlen(linkbuf) - zoneInfoDirLen, kCFStringEncodingUTF8, false);
         } else {
             name = CFStringCreateWithBytes(kCFAllocatorSystemDefault, (uint8_t *)linkbuf, strlen(linkbuf), kCFStringEncodingUTF8, false);
         }

Foundation/DateFormatter.swift

@@ -176,13 +176,13 @@ open class DateFormatter : Formatter {
     /*@NSCopying*/ internal var _timeZone: TimeZone? { willSet { _reset() } }
     open var timeZone: TimeZone! {
         get {
-            guard let timeZone = _timeZone else {
+            guard let tz = _timeZone else {
                 return (CFDateFormatterCopyProperty(_cfObject, kCFDateFormatterTimeZone) as! NSTimeZone)._swiftObject
             }
-            return timeZone
+            return tz
         }
         set {
-            _timeZone = timeZone
+            _timeZone = newValue
         }
     }
 

TestFoundation/TestCalendar.swift

@@ -331,7 +331,16 @@ class TestNSDateComponents: XCTestCase {
         // 2286-11-20 17:46:41
         let date4 = Date(timeIntervalSince1970: 10_000_000_001)
 
-        let diff1 = Calendar.current.dateComponents([.month, .year, .day], from: date1, to: date2)
+        // The date components below assume UTC/GMT time zone.
+        guard let timeZone = TimeZone(abbreviation: "UTC") else {
+            XCTFail("Unable to create UTC TimeZone for Test")
+            return
+        }
+
+        var calendar = Calendar.current
+        calendar.timeZone = timeZone
+
+        let diff1 = calendar.dateComponents([.month, .year, .day], from: date1, to: date2)
         XCTAssertEqual(diff1.year, 1)
         XCTAssertEqual(diff1.month, 5)
         XCTAssertEqual(diff1.isLeapMonth, false)
@@ -350,35 +359,35 @@ class TestNSDateComponents: XCTestCase {
         XCTAssertNil(diff1.calendar)
         XCTAssertNil(diff1.timeZone)
 
-        let diff2 = Calendar.current.dateComponents([.weekOfMonth], from: date2, to: date1)
+        let diff2 = calendar.dateComponents([.weekOfMonth], from: date2, to: date1)
         XCTAssertEqual(diff2.weekOfMonth, -76)
         XCTAssertEqual(diff2.isLeapMonth, false)
 
-        let diff3 = Calendar.current.dateComponents([.weekday], from: date2, to: date1)
+        let diff3 = calendar.dateComponents([.weekday], from: date2, to: date1)
         XCTAssertEqual(diff3.weekday, -536)
         XCTAssertEqual(diff3.isLeapMonth, false)
 
-        let diff4 = Calendar.current.dateComponents([.weekday, .weekOfMonth], from: date1, to: date2)
+        let diff4 = calendar.dateComponents([.weekday, .weekOfMonth], from: date1, to: date2)
         XCTAssertEqual(diff4.weekday, 4)
         XCTAssertEqual(diff4.weekOfMonth, 76)
         XCTAssertEqual(diff4.isLeapMonth, false)
 
-        let diff5 = Calendar.current.dateComponents([.weekday, .weekOfYear], from: date1, to: date2)
+        let diff5 = calendar.dateComponents([.weekday, .weekOfYear], from: date1, to: date2)
         XCTAssertEqual(diff5.weekday, 4)
         XCTAssertEqual(diff5.weekOfYear, 76)
         XCTAssertEqual(diff5.isLeapMonth, false)
 
-        let diff6 = Calendar.current.dateComponents([.month, .weekOfMonth], from: date1, to: date2)
+        let diff6 = calendar.dateComponents([.month, .weekOfMonth], from: date1, to: date2)
         XCTAssertEqual(diff6.month, 17)
         XCTAssertEqual(diff6.weekOfMonth, 2)
         XCTAssertEqual(diff6.isLeapMonth, false)
 
-        let diff7 = Calendar.current.dateComponents([.weekOfYear, .weekOfMonth], from: date2, to: date1)
+        let diff7 = calendar.dateComponents([.weekOfYear, .weekOfMonth], from: date2, to: date1)
         XCTAssertEqual(diff7.weekOfYear, -76)
         XCTAssertEqual(diff7.weekOfMonth, 0)
         XCTAssertEqual(diff7.isLeapMonth, false)
 
-        let diff8 = Calendar.current.dateComponents([.era, .quarter, .year, .month, .day, .hour, .minute, .second, .nanosecond, .calendar, .timeZone], from: date2, to: date3)
+        let diff8 = calendar.dateComponents([.era, .quarter, .year, .month, .day, .hour, .minute, .second, .nanosecond, .calendar, .timeZone], from: date2, to: date3)
         XCTAssertEqual(diff8.era, 0)
         XCTAssertEqual(diff8.year, 315)
         XCTAssertEqual(diff8.quarter, 0)
@@ -392,7 +401,7 @@ class TestNSDateComponents: XCTestCase {
         XCTAssertNil(diff8.calendar)
         XCTAssertNil(diff8.timeZone)
 
-        let diff9 = Calendar.current.dateComponents([.era, .quarter, .year, .month, .day, .hour, .minute, .second, .nanosecond, .calendar, .timeZone], from: date4, to: date3)
+        let diff9 = calendar.dateComponents([.era, .quarter, .year, .month, .day, .hour, .minute, .second, .nanosecond, .calendar, .timeZone], from: date4, to: date3)
         XCTAssertEqual(diff9.era, 0)
         XCTAssertEqual(diff9.year, 0)
         XCTAssertEqual(diff9.quarter, 0)

TestFoundation/TestDateFormatter.swift

@@ -24,6 +24,8 @@ class TestDateFormatter: XCTestCase {
             ("test_dateFormatString", test_dateFormatString),
             ("test_setLocaleToNil", test_setLocaleToNil),
             ("test_setTimeZoneToNil", test_setTimeZoneToNil),
+            ("test_setTimeZone", test_setTimeZone),
+            ("test_expectedTimeZone", test_expectedTimeZone),
         ]
     }
 
@@ -356,4 +358,54 @@ class TestDateFormatter: XCTestCase {
         // Time zone should go back to the system one.
         XCTAssertEqual(f.timeZone, NSTimeZone.system)
     }
+
+    func test_setTimeZone() {
+        // Test two different time zones. Should ensure that if one
+        // happens to be TimeZone.current, we still get a valid test.
+        let newYork = TimeZone(identifier: "America/New_York")!
+        let losAngeles = TimeZone(identifier: "America/Los_Angeles")!
+
+        XCTAssertNotEqual(newYork, losAngeles)
+
+        // Case 1: New York
+        let f = DateFormatter()
+        f.timeZone = newYork
+        XCTAssertEqual(f.timeZone, newYork)
+
+        // Case 2: Los Angeles
+        f.timeZone = losAngeles
+        XCTAssertEqual(f.timeZone, losAngeles)
+    }
+
+    func test_expectedTimeZone() {
+        let gmt = TimeZone(abbreviation: DEFAULT_TIMEZONE)
+        let newYork = TimeZone(identifier: "America/New_York")!
+        let losAngeles = TimeZone(identifier: "America/Los_Angeles")!
+
+        XCTAssertNotEqual(newYork, losAngeles)
+
+        let now = Date()
+
+        let f = DateFormatter()
+        f.dateFormat = "z"
+        f.locale = Locale(identifier: "en_US_POSIX")
+
+        // Case 1: TimeZone.current
+        // This case can catch some issues that cause TimeZone.current to be
+        // treated like GMT, but it doesn't work if TimeZone.current is GMT.
+        // If you do find an issue like this caused by this first case,
+        // it would benefit from a more specific test that fails when
+        // TimeZone.current is GMT as well.
+        // (ex. TestTimeZone.test_systemTimeZoneName)
+        f.timeZone = TimeZone.current
+        XCTAssertEqual(f.string(from: now), TimeZone.current.abbreviation())
+
+        // Case 2: New York
+        f.timeZone = newYork
+        XCTAssertEqual(f.string(from: now), newYork.abbreviation())
+
+        // Case 3: Los Angeles
+        f.timeZone = losAngeles
+        XCTAssertEqual(f.string(from: now), losAngeles.abbreviation())
+    }
 }

TestFoundation/TestTimeZone.swift

@@ -7,6 +7,8 @@
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 
+import CoreFoundation
+
 class TestTimeZone: XCTestCase {
 
     static var allTests: [(String, (TestTimeZone) -> () throws -> Void)] {
@@ -29,6 +31,7 @@ class TestTimeZone: XCTestCase {
 
             ("test_customMirror", test_tz_customMirror),
             ("test_knownTimeZones", test_knownTimeZones),
+            ("test_systemTimeZoneName", test_systemTimeZoneName),
         ]
     }
 
@@ -198,4 +201,17 @@ class TestTimeZone: XCTestCase {
             XCTAssertNotNil(TimeZone(identifier: tz), "Cant instantiate valid timeZone: \(tz)")
         }
     }
+
+    func test_systemTimeZoneName() {
+        // Ensure that the system time zone creates names the same way as creating them with an identifier.
+        // If it isn't the same, bugs in DateFormat can result, but in this specific case, the bad length
+        // is only visible to CoreFoundation APIs, and the Swift versions hide it, making it hard to detect.
+        let timeZone = CFTimeZoneCopySystem()
+        let timeZoneName = CFTimeZoneGetName(timeZone)
+
+        let createdTimeZone = TimeZone(identifier: TimeZone.current.identifier)!
+
+        XCTAssertEqual(CFStringGetLength(timeZoneName), TimeZone.current.identifier.count)
+        XCTAssertEqual(CFStringGetLength(timeZoneName), createdTimeZone.identifier.count)
+    }
 }