gengliangwang commented on code in PR #37486:
URL: https://github.com/apache/spark/pull/37486#discussion_r944181199
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sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Cast.scala:
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@@ -460,29 +500,57 @@ case class Cast(
final override def nodePatternsInternal(): Seq[TreePattern] = Seq(CAST)
- private def typeCheckFailureMessage: String = if (ansiEnabled) {
- if (getTagValue(Cast.BY_TABLE_INSERTION).isDefined) {
- Cast.typeCheckFailureMessage(child.dataType, dataType,
- Some(SQLConf.STORE_ASSIGNMENT_POLICY.key ->
SQLConf.StoreAssignmentPolicy.LEGACY.toString))
- } else {
- Cast.typeCheckFailureMessage(child.dataType, dataType,
- Some(SQLConf.ANSI_ENABLED.key -> "false"))
- }
- } else {
- s"cannot cast ${child.dataType.catalogString} to ${dataType.catalogString}"
+ def ansiEnabled: Boolean = {
+ evalMode == EvalMode.ANSI || evalMode == EvalMode.TRY
+ }
+
+ // Whether this expression is used for `try_cast()`.
+ def isTryCast: Boolean = {
+ evalMode == EvalMode.TRY
+ }
+
+ private def typeCheckFailureMessage: String = evalMode match {
+ case EvalMode.ANSI =>
+ if (getTagValue(Cast.BY_TABLE_INSERTION).isDefined) {
+ Cast.typeCheckFailureMessage(child.dataType, dataType,
+ Some(SQLConf.STORE_ASSIGNMENT_POLICY.key ->
+ SQLConf.StoreAssignmentPolicy.LEGACY.toString))
+ } else {
+ Cast.typeCheckFailureMessage(child.dataType, dataType,
+ Some(SQLConf.ANSI_ENABLED.key -> "false"))
+ }
+ case EvalMode.TRY =>
+ Cast.typeCheckFailureMessage(child.dataType, dataType, None)
+ case _ =>
+ s"cannot cast ${child.dataType.catalogString} to
${dataType.catalogString}"
}
override def checkInputDataTypes(): TypeCheckResult = {
- if (ansiEnabled && Cast.canAnsiCast(child.dataType, dataType)) {
- TypeCheckResult.TypeCheckSuccess
- } else if (!ansiEnabled && Cast.canCast(child.dataType, dataType)) {
+ val canCast = evalMode match {
+ case EvalMode.LEGACY => Cast.canCast(child.dataType, dataType)
+ case EvalMode.ANSI => Cast.canAnsiCast(child.dataType, dataType)
+ case EvalMode.TRY => Cast.canTryCast(child.dataType, dataType)
+ case other => throw new IllegalArgumentException(s"Unknown EvalMode
value: $other")
+ }
+ if (canCast) {
TypeCheckResult.TypeCheckSuccess
} else {
TypeCheckResult.TypeCheckFailure(typeCheckFailureMessage)
}
}
- override def nullable: Boolean = child.nullable ||
Cast.forceNullable(child.dataType, dataType)
+ override def nullable: Boolean = if (!isTryCast) {
+ child.nullable || Cast.forceNullable(child.dataType, dataType)
+ } else {
+ (child.dataType, dataType) match {
+ case (StringType, BinaryType) => child.nullable
+ // TODO: Implement a more accurate method for checking whether a decimal
value can be cast
+ // as integral types without overflow. Currently, the cast can
overflow even if
+ // "Cast.canUpCast" method returns true.
+ case (_: DecimalType, _: IntegralType) => true
Review Comment:
Decimal(10, 0) is considered as "canUpCast" as Int. However, `Int.MaxValue +
1` can fit in Decimal(10, 0) too..
It has been a long time and the strict table insertion policy relies on
this.
I would consider fixing it in another PR. For this one I will leave it as it
is now.
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