feat: add GetTimestamp support via codegen dispatcher

spark/src/main/scala/org/apache/comet/serde/QueryPlanSerde.scala

@@ -233,6 +233,7 @@ object QueryPlanSerde extends Logging with CometExprShim with CometTypeShim {
       classOf[FromUnixTime] -> CometFromUnixTime,
       classOf[FromUTCTimestamp] -> CometFromUTCTimestamp,
       classOf[ToUTCTimestamp] -> CometToUTCTimestamp,
+      classOf[GetTimestamp] -> CometGetTimestamp,
       classOf[LastDay] -> CometLastDay,
       classOf[Hour] -> CometHour,
       classOf[MakeDate] -> CometMakeDate,

spark/src/main/scala/org/apache/comet/serde/datetime.scala

@@ -21,7 +21,7 @@ package org.apache.comet.serde
 
 import java.util.Locale
 
-import org.apache.spark.sql.catalyst.expressions.{AddMonths, Attribute, ConvertTimezone, DateAdd, DateDiff, DateFormatClass, DateFromUnixDate, DateSub, DayOfMonth, DayOfWeek, DayOfYear, Days, FromUTCTimestamp, GetDateField, Hour, Hours, LastDay, Literal, MakeDate, MakeTimestamp, MicrosToTimestamp, MillisToTimestamp, Minute, Month, MonthsBetween, NextDay, Quarter, Second, SecondsToTimestamp, ToUnixTimestamp, ToUTCTimestamp, TruncDate, TruncTimestamp, UnixDate, UnixMicros, UnixMillis, UnixSeconds, UnixTimestamp, WeekDay, WeekOfYear, Year}
+import org.apache.spark.sql.catalyst.expressions.{AddMonths, Attribute, ConvertTimezone, DateAdd, DateDiff, DateFormatClass, DateFromUnixDate, DateSub, DayOfMonth, DayOfWeek, DayOfYear, Days, FromUTCTimestamp, GetDateField, GetTimestamp, Hour, Hours, LastDay, Literal, MakeDate, MakeTimestamp, MicrosToTimestamp, MillisToTimestamp, Minute, Month, MonthsBetween, NextDay, Quarter, Second, SecondsToTimestamp, ToUnixTimestamp, ToUTCTimestamp, TruncDate, TruncTimestamp, UnixDate, UnixMicros, UnixMillis, UnixSeconds, UnixTimestamp, WeekDay, WeekOfYear, Year}
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types.{DateType, DoubleType, FloatType, IntegerType, LongType, StringType, TimestampNTZType, TimestampType}
 import org.apache.spark.unsafe.types.UTF8String
@@ -789,3 +789,5 @@ object CometUnixMillis extends CometCodegenDispatch[UnixMillis]
 object CometUnixMicros extends CometCodegenDispatch[UnixMicros]
 
 object CometToUnixTimestamp extends CometCodegenDispatch[ToUnixTimestamp]
+
+object CometGetTimestamp extends CometCodegenDispatch[GetTimestamp]

spark/src/test/resources/sql-tests/expressions/datetime/get_timestamp.sql

@@ -0,0 +1,95 @@
+-- Licensed to the Apache Software Foundation (ASF) under one
+-- or more contributor license agreements.  See the NOTICE file
+-- distributed with this work for additional information
+-- regarding copyright ownership.  The ASF licenses this file
+-- to you under the Apache License, Version 2.0 (the
+-- "License"); you may not use this file except in compliance
+-- with the License.  You may obtain a copy of the License at
+--
+--   http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing,
+-- software distributed under the License is distributed on an
+-- "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+-- KIND, either express or implied.  See the License for the
+-- specific language governing permissions and limitations
+-- under the License.
+
+-- Routes GetTimestamp through the codegen dispatcher.
+-- GetTimestamp is generated by to_timestamp(string, format), to_date(string, format)
+-- and try_to_timestamp(string, format).
+-- Config: spark.sql.session.timeZone=UTC
+-- Config: spark.comet.exec.scalaUDF.codegen.enabled=true
+
+statement
+CREATE TABLE test_get_timestamp(s string) USING parquet
+
+statement
+INSERT INTO test_get_timestamp VALUES
+  ('2024-06-15 10:30:45'),
+  ('1970-01-01 00:00:00'),
+  ('1969-12-31 23:59:59'),
+  ('2024-13-01 00:00:00'),
+  ('garbage'),
+  (''),
+  (NULL)
+
+-- to_timestamp(string, format) -> GetTimestamp with TimestampType output
+query
+SELECT to_timestamp(s, 'yyyy-MM-dd HH:mm:ss') FROM test_get_timestamp
+
+-- to_date(string, format) -> Cast(GetTimestamp(...), DateType)
+query
+SELECT to_date(s, 'yyyy-MM-dd HH:mm:ss') FROM test_get_timestamp
+
+-- try_to_timestamp(string, format) -> GetTimestamp with failOnError=false
+query
+SELECT try_to_timestamp(s, 'yyyy-MM-dd HH:mm:ss') FROM test_get_timestamp
+
+-- literal arguments
+query
+SELECT to_timestamp('2024-06-15 10:30:45', 'yyyy-MM-dd HH:mm:ss')
+
+query
+SELECT to_date('2024-06-15', 'yyyy-MM-dd')
+
+query
+SELECT try_to_timestamp('foo', 'yyyy-MM-dd')
+
+query
+SELECT to_timestamp(NULL, 'yyyy-MM-dd HH:mm:ss')
+
+-- date-only format
+statement
+CREATE TABLE test_get_timestamp_dates(s string) USING parquet
+
+statement
+INSERT INTO test_get_timestamp_dates VALUES
+  ('2024-06-15'),
+  ('1970-01-01'),
+  (NULL)
+
+query
+SELECT to_timestamp(s, 'yyyy-MM-dd') FROM test_get_timestamp_dates
+
+query
+SELECT to_date(s, 'yyyy-MM-dd') FROM test_get_timestamp_dates
+
+-- column-as-format (non-literal format)
+statement
+CREATE TABLE test_get_timestamp_fmt(s string, fmt string) USING parquet
+
+statement
+INSERT INTO test_get_timestamp_fmt VALUES
+  ('2024-06-15 10:30:45', 'yyyy-MM-dd HH:mm:ss'),
+  ('2024-06-15', 'yyyy-MM-dd'),
+  ('06/15/2024', 'MM/dd/yyyy'),
+  (NULL, 'yyyy-MM-dd'),
+  ('2024-06-15', NULL)
+
+query
+SELECT to_timestamp(s, fmt) FROM test_get_timestamp_fmt
+
+-- to_timestamp_ntz(string, format) -> GetTimestamp with TimestampNTZType output
+query
+SELECT to_timestamp_ntz(s, 'yyyy-MM-dd HH:mm:ss') FROM test_get_timestamp

spark/src/test/resources/sql-tests/expressions/datetime/get_timestamp_ansi.sql

@@ -0,0 +1,46 @@
+-- Licensed to the Apache Software Foundation (ASF) under one
+-- or more contributor license agreements.  See the NOTICE file
+-- distributed with this work for additional information
+-- regarding copyright ownership.  The ASF licenses this file
+-- to you under the Apache License, Version 2.0 (the
+-- "License"); you may not use this file except in compliance
+-- with the License.  You may obtain a copy of the License at
+--
+--   http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing,
+-- software distributed under the License is distributed on an
+-- "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+-- KIND, either express or implied.  See the License for the
+-- specific language governing permissions and limitations
+-- under the License.
+
+-- ANSI mode: GetTimestamp throws on parse failure. The codegen dispatcher inherits
+-- the throw from Spark's own GetTimestamp.doGenCode. The time parser policy is pinned
+-- to CORRECTED so the JDK java.time formatter (and the CANNOT_PARSE_TIMESTAMP error class)
+-- is exercised regardless of the runtime default.
+-- Config: spark.sql.session.timeZone=UTC
+-- Config: spark.sql.ansi.enabled=true
+-- Config: spark.sql.legacy.timeParserPolicy=CORRECTED
+-- Config: spark.comet.exec.scalaUDF.codegen.enabled=true
+-- The CANNOT_PARSE_TIMESTAMP error class was standardized in Spark 3.5.
+-- MinSparkVersion: 3.5
+
+query expect_error(CANNOT_PARSE_TIMESTAMP)
+SELECT to_timestamp('not a date', 'yyyy-MM-dd')
+
+query expect_error(CANNOT_PARSE_TIMESTAMP)
+SELECT to_timestamp('2024-13-99', 'yyyy-MM-dd')
+
+query expect_error(CANNOT_PARSE_TIMESTAMP)
+SELECT to_date('not a date', 'yyyy-MM-dd')
+
+-- try_to_timestamp does NOT throw under ANSI mode (failOnError=false)
+query
+SELECT try_to_timestamp('not a date', 'yyyy-MM-dd')
+
+-- Sentinel: confirms Comet ran the expression natively. If the dispatcher silently rejects
+-- GetTimestamp, the error queries above pass vacuously via Spark fallback. This valid
+-- query uses checkSparkAnswerAndOperator and fails if Comet did not execute it natively.
+query
+SELECT to_timestamp('2024-06-15 10:30:45', 'yyyy-MM-dd HH:mm:ss')