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fix: Fix UTC<->Timezone conversion issue for DST start and end timestamp #2260

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fix: Fix UTC<->Timezone conversion issue for DST start and end timestamp #2260

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13 changes: 11 additions & 2 deletions src/main/java/com/google/cloud/spanner/jdbc/JdbcTypeConverter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,7 @@
import java.util.Arrays;
import java.util.Calendar;
import java.util.List;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;

/** Convenience class for converting values between Java, JDBC and Cloud Spanner. */
Expand Down Expand Up @@ -496,10 +497,18 @@ private static java.sql.Timestamp getOrSetTimestampInCalendar(
Calendar newCal = Calendar.getInstance(cal.getTimeZone());
// set the millisecond time on this calendar from the timestamp
newCal.setTimeInMillis(sqlTs.getTime());
newCal.set(Calendar.MILLISECOND, 0);

TimeZone timeZone = newCal.getTimeZone();
long totalMillis = newCal.getTimeInMillis();
// to calculate the offset for DST correctly, we need to add DST savings and check if
// given epoch milli is in daylight savings time.
if (getOrSet == GetOrSetTimestampInCalendar.GET) {
totalMillis += timeZone.getRawOffset() + timeZone.getDSTSavings();
}

// then shift the time of the calendar by the difference between UTC and the timezone of the
// given calendar
int offset = newCal.getTimeZone().getOffset(newCal.getTimeInMillis());
int offset = newCal.getTimeZone().getOffset(totalMillis);
newCal.add(
Calendar.MILLISECOND, getOrSet == GetOrSetTimestampInCalendar.GET ? offset : -offset);
// then use that to create a sql timestamp
Expand Down
25 changes: 25 additions & 0 deletions src/test/java/com/google/cloud/spanner/jdbc/JdbcTypeConverterTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,8 @@
import java.sql.Time;
import java.sql.Timestamp;
import java.text.DecimalFormat;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
Expand Down Expand Up @@ -959,6 +961,29 @@ public void testDateToSqlTimestampWithCalendar() {
.toSqlTimestamp());
}

@Test
public void testDateToSqlTimestampWithCalendarWithStartOfDST() {
TimeZone timeZone = TimeZone.getTimeZone("Europe/Oslo");

List<ZonedDateTime> zonedDateTimes =
Arrays.asList(
ZonedDateTime.of(2018, 3, 25, 2, 0, 0, 0, ZoneId.of("+01:00")),
ZonedDateTime.of(2018, 10, 28, 2, 0, 0, 0, ZoneId.of("+01:00")));

zonedDateTimes.forEach(
expected -> {
Timestamp expectedTimestamp = Timestamp.from(expected.toInstant());
Calendar cal = Calendar.getInstance(timeZone);
Timestamp storeTimestamp =
JdbcTypeConverter.setTimestampInCalendar(expectedTimestamp, cal);

Timestamp resultTimestamp = JdbcTypeConverter.getTimestampInCalendar(storeTimestamp, cal);
ZonedDateTime actual = resultTimestamp.toInstant().atZone(timeZone.toZoneId());

assertThat(actual).isEqualTo(expected.withZoneSameInstant(timeZone.toZoneId()));
});
}

@Test
public void testParseSqlTimeWithCalendar() {
assertThat(
Expand Down