Add allowOverflow flag to Timestamp::toTimezone (facebookincubator#9836)

Summary:
Allow integer overflow when converting timestamp to TimePoint.

Use in Spark function from_unixtime that allows overflow.

Fixes facebookincubator#9778

Pull Request resolved: facebookincubator#9836

Reviewed By: amitkdutta

Differential Revision: D57659010

Pulled By: mbasmanova

fbshipit-source-id: d60fd686c19dff02eebba1a0c0410056d189c6f5

velox/docs/functions/spark/datetime.rst

@@ -93,6 +93,12 @@ These functions support TIMESTAMP and DATE input types.
         SELECT from_unixtime(3600, 'yyyy'); -- '1970'
         SELECT from_unixtime(9223372036854775807, "yyyy-MM-dd HH:mm:ss");  -- '1969-12-31 23:59:59'
 
+    If we run the following query in the `Asia/Shanghai` time zone: ::
+
+        SELECT from_unixtime(100, 'yyyy-MM-dd HH:mm:ss'); -- '1970-01-01 08:01:40'
+        SELECT from_unixtime(3600, 'yyyy'); -- '1970'
+        SELECT from_unixtime(9223372036854775807, "yyyy-MM-dd HH:mm:ss");  -- '1970-01-01 07:59:59'
+
 .. spark:function:: from_utc_timestamp(timestamp, string) -> timestamp
 
     Returns the timestamp value from UTC timezone to the given timezone. ::

velox/functions/lib/DateTimeFormatter.cpp

@@ -1033,7 +1033,7 @@ int32_t DateTimeFormatter::format(
     bool allowOverflow) const {
   Timestamp t = timestamp;
   if (timezone != nullptr) {
-    t.toTimezone(*timezone);
+    t.toTimezone(*timezone, allowOverflow);
   }
   const auto timePoint = t.toTimePoint(allowOverflow);
   const auto daysTimePoint = date::floor<date::days>(timePoint);

velox/functions/sparksql/tests/DateTimeFunctionsTest.cpp

@@ -898,6 +898,15 @@ TEST_F(DateTimeFunctionsTest, fromUnixtime) {
 
   // 8 hours ahead UTC.
   setQueryTimeZone("Asia/Shanghai");
+// In debug mode, Timestamp constructor will throw exception if range check
+// fails.
+#ifdef NDEBUG
+  // Integer overflow in the internal conversion from seconds to milliseconds.
+  EXPECT_EQ(
+      fromUnixTime(std::numeric_limits<int64_t>::max(), "yyyy-MM-dd HH:mm:ss"),
+      "1970-01-01 07:59:59");
+#endif
+
   EXPECT_EQ(fromUnixTime(0, "yyyy-MM-dd HH:mm:ss"), "1970-01-01 08:00:00");
   EXPECT_EQ(fromUnixTime(120, "yyyy-MM-dd HH:mm"), "1970-01-01 08:02");
   EXPECT_EQ(fromUnixTime(-59, "yyyy-MM-dd HH:mm:ss"), "1970-01-01 07:59:01");

velox/type/Timestamp.cpp

@@ -118,8 +118,8 @@ Timestamp::toTimePoint(bool allowOverflow) const {
   return tp;
 }
 
-void Timestamp::toTimezone(const date::time_zone& zone) {
-  auto tp = toTimePoint();
+void Timestamp::toTimezone(const date::time_zone& zone, bool allowOverflow) {
+  auto tp = toTimePoint(allowOverflow);
   auto epoch = zone.to_local(tp).time_since_epoch();
   // NOTE: Round down to get the seconds of the current time point.
   seconds_ = std::chrono::floor<std::chrono::seconds>(epoch).count();

velox/type/Timestamp.h

@@ -187,7 +187,7 @@ struct Timestamp {
   /// Due to the limit of std::chrono, throws if timestamp is outside of
   /// [-32767-01-01, 32767-12-31] range.
   /// If allowOverflow is true, integer overflow is allowed in converting
-  /// timestmap to milliseconds.
+  /// timestamp to milliseconds.
   std::chrono::time_point<std::chrono::system_clock, std::chrono::milliseconds>
   toTimePoint(bool allowOverflow = false) const;
 
@@ -311,12 +311,14 @@ struct Timestamp {
   // Same as above, but accepts PrestoDB time zone ID.
   void toGMT(int16_t tzID);
 
-  // Assuming the timestamp represents a GMT time, converts it to the time at
-  // the same moment at zone.
-  // Example: Timestamp ts{0, 0};
-  // ts.Timezone("America/Los_Angeles");
-  // ts.toString() returns December 31, 1969 16:00:00
-  void toTimezone(const date::time_zone& zone);
+  /// Assuming the timestamp represents a GMT time, converts it to the time at
+  /// the same moment at zone.
+  /// @param allowOverflow If true, integer overflow is allowed when converting
+  /// timestamp to TimePoint. Otherwise, user exception is thrown for overflow.
+  /// Example: Timestamp ts{0, 0};
+  /// ts.Timezone("America/Los_Angeles");
+  /// ts.toString() returns December 31, 1969 16:00:00
+  void toTimezone(const date::time_zone& zone, bool allowOverflow = false);
 
   // Same as above, but accepts PrestoDB time zone ID.
   void toTimezone(int16_t tzID);