uros-b commented on code in PR #56810:
URL: https://github.com/apache/spark/pull/56810#discussion_r3481712835
##########
sql/api/src/main/scala/org/apache/spark/sql/types/UpCastRule.scala:
##########
@@ -36,10 +36,17 @@ private[sql] object UpCastRule {
case (from: NumericType, to: DecimalType) if to.isWiderThan(from) => true
case (from: DecimalType, to: NumericType) if from.isTighterThan(to) => true
case (f, t) if legalNumericPrecedence(f, t) => true
- case (DateType, TimestampType) => true
- case (DateType, TimestampNTZType) => true
- case (TimestampNTZType, TimestampType) => true
- case (TimestampType, TimestampNTZType) => true
+ // Widening DATE -> timestamp family (micro or nanos, LTZ or NTZ) is
lossless; the reverse
+ // (timestamp -> DATE) drops the time-of-day and is not matched here, so
it stays a non-up-cast.
+ case (DateType, t) if TimestampFamily.fractionalPrecision(t).isDefined =>
true
+ // Lossless widening within the timestamp family: target fractional-second
precision >= source.
+ // Covers micros <-> nanos and the cross-family LTZ <-> NTZ pairs
(mirroring how the micro
+ // TimestampType <-> TimestampNTZType pair is a mutual up-cast). Equal
precision is handled by
+ // the `from == to` short-circuit above; lossy narrowing falls through to
`case _ => false`.
+ case (f, t)
+ if TimestampFamily.fractionalPrecision(f).isDefined &&
+ TimestampFamily.fractionalPrecision(t).isDefined =>
+ TimestampFamily.fractionalPrecision(f).get <=
TimestampFamily.fractionalPrecision(t).get
Review Comment:
```suggestion
case (f, t) =>
TimestampFamily.fractionalPrecision(f).exists(fp =>
TimestampFamily.fractionalPrecision(t).exists(fp <= _))
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
