diff options
| -rw-r--r-- | src/time/time.go | 14 | ||||
| -rw-r--r-- | src/time/time_test.go | 42 |
2 files changed, 49 insertions, 7 deletions
diff --git a/src/time/time.go b/src/time/time.go index 8ae62308e5b..c8f8b9081a1 100644 --- a/src/time/time.go +++ b/src/time/time.go @@ -1373,17 +1373,17 @@ func Date(year int, month Month, day, hour, min, sec, nsec int, loc *Location) T unix := int64(abs) + (absoluteToInternal + internalToUnix) - // Look for zone offset for t, so we can adjust to UTC. - // The lookup function expects UTC, so we pass t in the + // Look for zone offset for expected time, so we can adjust to UTC. + // The lookup function expects UTC, so first we pass unix in the // hope that it will not be too close to a zone transition, // and then adjust if it is. _, offset, start, end := loc.lookup(unix) if offset != 0 { - switch utc := unix - int64(offset); { - case utc < start: - _, offset, _, _ = loc.lookup(start - 1) - case utc >= end: - _, offset, _, _ = loc.lookup(end) + utc := unix - int64(offset) + // If utc is valid for the time zone we found, then we have the right offset. + // If not, we get the correct offset by looking up utc in the location. + if utc < start || utc >= end { + _, offset, _, _ = loc.lookup(utc) } unix -= int64(offset) } diff --git a/src/time/time_test.go b/src/time/time_test.go index 154198a1ce6..d1b9e764f55 100644 --- a/src/time/time_test.go +++ b/src/time/time_test.go @@ -1465,3 +1465,45 @@ func TestConcurrentTimerResetStop(t *testing.T) { } wg.Wait() } + +// Issue 49284: time: ParseInLocation incorrectly because of Daylight Saving Time +func TestTimeWithZoneTransition(t *testing.T) { + ForceZipFileForTesting(true) + defer ForceZipFileForTesting(false) + + loc, err := LoadLocation("Asia/Shanghai") + if err != nil { + t.Fatal(err) + } + + tests := [...]struct { + give Time + want Time + }{ + // 14 Apr 1991 - Daylight Saving Time Started + // When time of "Asia/Shanghai" was about to reach + // Sunday, 14 April 1991, 02:00:00 clocks were turned forward 1 hour to + // Sunday, 14 April 1991, 03:00:00 local daylight time instead. + // The UTC time was 13 April 1991, 18:00:00 + 0: {Date(1991, April, 13, 17, 50, 0, 0, loc), Date(1991, April, 13, 9, 50, 0, 0, UTC)}, + 1: {Date(1991, April, 13, 18, 0, 0, 0, loc), Date(1991, April, 13, 10, 0, 0, 0, UTC)}, + 2: {Date(1991, April, 14, 1, 50, 0, 0, loc), Date(1991, April, 13, 17, 50, 0, 0, UTC)}, + 3: {Date(1991, April, 14, 3, 0, 0, 0, loc), Date(1991, April, 13, 18, 0, 0, 0, UTC)}, + + // 15 Sep 1991 - Daylight Saving Time Ended + // When local daylight time of "Asia/Shanghai" was about to reach + // Sunday, 15 September 1991, 02:00:00 clocks were turned backward 1 hour to + // Sunday, 15 September 1991, 01:00:00 local standard time instead. + // The UTC time was 14 September 1991, 17:00:00 + 4: {Date(1991, September, 14, 16, 50, 0, 0, loc), Date(1991, September, 14, 7, 50, 0, 0, UTC)}, + 5: {Date(1991, September, 14, 17, 0, 0, 0, loc), Date(1991, September, 14, 8, 0, 0, 0, UTC)}, + 6: {Date(1991, September, 15, 0, 50, 0, 0, loc), Date(1991, September, 14, 15, 50, 0, 0, UTC)}, + 7: {Date(1991, September, 15, 2, 00, 0, 0, loc), Date(1991, September, 14, 18, 00, 0, 0, UTC)}, + } + + for i, tt := range tests { + if !tt.give.Equal(tt.want) { + t.Errorf("#%d:: %#v is not equal to %#v", i, tt.give.Format(RFC3339), tt.want.Format(RFC3339)) + } + } +} |