[SPARK-52618][SQL] Casting TIME(n) to TIME(m)

### What changes were proposed in this pull request?
In the PR, I propose to support casting from TIME(n) to TIME(m) for any n, m in the range [0, 6].

### Why are the changes needed?
Users can change precision of TIME values.

### Does this PR introduce _any_ user-facing change?
No, the TIME data type hasn't been released yet.

### How was this patch tested?
By running new tests:
```
$ build/sbt "sql/testOnly org.apache.spark.sql.SQLQueryTestSuite -- -z time.sql"
```

### Was this patch authored or co-authored using generative AI tooling?
No.

Closes #51361 from MaxGekk/cast-time-to-time-2.

Authored-by: Max Gekk <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: MaxGekk

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Cast.scala

@@ -134,6 +134,8 @@ object Cast extends QueryErrorsBase {
     // to convert data of these types to Variant Objects.
     case (_, VariantType) => variant.VariantGet.checkDataType(from, allowStructsAndMaps = false)
 
+    case (_: TimeType, _: TimeType) => true
+
     // non-null variants can generate nulls even in ANSI mode
     case (ArrayType(fromType, fn), ArrayType(toType, tn)) =>
       canAnsiCast(fromType, toType) && resolvableNullability(fn || (fromType == VariantType), tn)
@@ -251,6 +253,8 @@ object Cast extends QueryErrorsBase {
     // to convert data of these types to Variant Objects.
     case (_, VariantType) => variant.VariantGet.checkDataType(from, allowStructsAndMaps = false)
 
+    case (_: TimeType, _: TimeType) => true
+
     case (ArrayType(fromType, fn), ArrayType(toType, tn)) =>
       canCast(fromType, toType) &&
         resolvableNullability(fn || forceNullable(fromType, toType), tn)
@@ -733,13 +737,15 @@ case class Cast(
       buildCast[Long](_, t => microsToDays(t, ZoneOffset.UTC))
   }
 
-  private[this] def castToTime(from: DataType): Any => Any = from match {
+  private[this] def castToTime(from: DataType, to: TimeType): Any => Any = from match {
     case _: StringType =>
       if (ansiEnabled) {
         buildCast[UTF8String](_, s => DateTimeUtils.stringToTimeAnsi(s, getContextOrNull()))
       } else {
         buildCast[UTF8String](_, s => DateTimeUtils.stringToTime(s).orNull)
       }
+    case _: TimeType =>
+      buildCast[Long](_, nanos => DateTimeUtils.truncateTimeToPrecision(nanos, to.precision))
   }
 
   // IntervalConverter
@@ -1149,7 +1155,7 @@ case class Cast(
         case s: StringType => castToString(from, s.constraint)
         case BinaryType => castToBinary(from)
         case DateType => castToDate(from)
-        case _: TimeType => castToTime(from)
+        case it: TimeType => castToTime(from, it)
         case decimal: DecimalType => castToDecimal(from, decimal)
         case TimestampType => castToTimestamp(from)
         case TimestampNTZType => castToTimestampNTZ(from)
@@ -1257,7 +1263,7 @@ case class Cast(
       (c, evPrim, _) => castToStringCode(from, ctx, s.constraint).apply(c, evPrim)
     case BinaryType => castToBinaryCode(from)
     case DateType => castToDateCode(from, ctx)
-    case _: TimeType => castToTimeCode(from, ctx)
+    case it: TimeType => castToTimeCode(from, it, ctx)
     case decimal: DecimalType => castToDecimalCode(from, decimal, ctx)
     case TimestampType => castToTimestampCode(from, ctx)
     case TimestampNTZType => castToTimestampNTZCode(from, ctx)
@@ -1354,6 +1360,7 @@ case class Cast(
 
   private[this] def castToTimeCode(
       from: DataType,
+      to: TimeType,
       ctx: CodegenContext): CastFunction = {
     from match {
       case _: StringType =>
@@ -1374,7 +1381,11 @@ case class Cast(
               }
             """
           }
-
+      case _: TimeType =>
+        (nanos, evPrim, _) =>
+          code"""
+            $evPrim = $dateTimeUtilsCls.truncateTimeToPrecision($nanos, ${to.precision});
+          """
       case _ =>
         (_, _, evNull) => code"$evNull = true;"
     }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/CastSuiteBase.scala

@@ -1484,4 +1484,27 @@ abstract class CastSuiteBase extends SparkFunSuite with ExpressionEvalHelper {
     checkEvaluation(cast(Literal.create("23:59:59.000001     "),
       TimeType(6)), localTime(23, 59, 59, 1))
   }
+
+  test("cast time to time") {
+    checkEvaluation(cast(Literal(localTime(), TimeType(0)), TimeType(0)), 0L)
+    checkEvaluation(cast(Literal(localTime(0, 0, 0, 1), TimeType(6)), TimeType(6)),
+      localTime(0, 0, 0, 1))
+    checkEvaluation(cast(Literal(localTime(0, 0, 0, 19), TimeType(6)), TimeType(5)),
+      localTime(0, 0, 0, 10))
+    checkEvaluation(cast(Literal(localTime(23, 59, 59, 999990), TimeType(5)), TimeType(6)),
+      localTime(23, 59, 59, 999990))
+    checkEvaluation(cast(Literal(localTime(23, 59, 59, 999999), TimeType(6)), TimeType(5)),
+      localTime(23, 59, 59, 999990))
+    checkEvaluation(cast(Literal(localTime(11, 58, 59, 123400), TimeType(4)), TimeType(5)),
+      localTime(11, 58, 59, 123400))
+    checkEvaluation(cast(Literal(localTime(19, 2, 3, 765000), TimeType(3)), TimeType(2)),
+      localTime(19, 2, 3, 760000))
+
+    for (sp <- TimeType.MIN_PRECISION to TimeType.MAX_PRECISION) {
+      for (tp <- TimeType.MIN_PRECISION to TimeType.MAX_PRECISION) {
+        checkConsistencyBetweenInterpretedAndCodegen(
+          (child: Expression) => Cast(child, TimeType(sp)), TimeType(tp))
+      }
+    }
+  }
 }

sql/core/src/test/resources/sql-tests/analyzer-results/time.sql.out

@@ -399,3 +399,24 @@ select extract(SECOND FROM cast('09:08:01.987654' as time(6)))
 -- !query analysis
 Project [extract(SECOND, cast(09:08:01.987654 as time(6))) AS extract(SECOND FROM CAST(09:08:01.987654 AS TIME(6)))#x]
 +- OneRowRelation
+
+
+-- !query
+SELECT cast(cast('12:00' as time(0)) as time(2))
+-- !query analysis
+Project [cast(cast(12:00 as time(0)) as time(2)) AS CAST(CAST(12:00 AS TIME(0)) AS TIME(2))#x]
++- OneRowRelation
+
+
+-- !query
+SELECT cast(('23:59:59.001001' :: time(6)) as time(4))
+-- !query analysis
+Project [cast(cast(23:59:59.001001 as time(6)) as time(4)) AS CAST(CAST(23:59:59.001001 AS TIME(6)) AS TIME(4))#x]
++- OneRowRelation
+
+
+-- !query
+SELECT cast(time'11:59:59.999999' as time without time zone)
+-- !query analysis
+Project [cast(11:59:59.999999 as time(6)) AS CAST(TIME '11:59:59.999999' AS TIME(6))#x]
++- OneRowRelation

sql/core/src/test/resources/sql-tests/inputs/time.sql

@@ -67,3 +67,8 @@ select extract(SECOND FROM cast('09:08:01.987654' as time(3)));
 select extract(SECOND FROM cast('09:08:01.987654' as time(4)));
 select extract(SECOND FROM cast('09:08:01.987654' as time(5)));
 select extract(SECOND FROM cast('09:08:01.987654' as time(6)));
+
+-- cast time to time
+SELECT cast(cast('12:00' as time(0)) as time(2));
+SELECT cast(('23:59:59.001001' :: time(6)) as time(4));
+SELECT cast(time'11:59:59.999999' as time without time zone);

sql/core/src/test/resources/sql-tests/results/time.sql.out

@@ -498,3 +498,27 @@ select extract(SECOND FROM cast('09:08:01.987654' as time(6)))
 struct<extract(SECOND FROM CAST(09:08:01.987654 AS TIME(6))):decimal(8,6)>
 -- !query output
 1.987654
+
+
+-- !query
+SELECT cast(cast('12:00' as time(0)) as time(2))
+-- !query schema
+struct<CAST(CAST(12:00 AS TIME(0)) AS TIME(2)):time(2)>
+-- !query output
+12:00:00
+
+
+-- !query
+SELECT cast(('23:59:59.001001' :: time(6)) as time(4))
+-- !query schema
+struct<CAST(CAST(23:59:59.001001 AS TIME(6)) AS TIME(4)):time(4)>
+-- !query output
+23:59:59.001
+
+
+-- !query
+SELECT cast(time'11:59:59.999999' as time without time zone)
+-- !query schema
+struct<CAST(TIME '11:59:59.999999' AS TIME(6)):time(6)>
+-- !query output
+11:59:59.999999