Major Description
Reducing Decimal scale by more than 18 produces exception.
Decimal(1, 38, 19).changePrecision(38, 0)
java.lang.ArrayIndexOutOfBoundsException: 19 at org.apache.spark.sql.types.Decimal.changePrecision(Decimal.scala:377) at org.apache.spark.sql.types.Decimal.changePrecision(Decimal.scala:328)
Reproducing with SQL query:
sql("select cast(cast(cast(cast(id as decimal(38,15)) as decimal(38,30)) as decimal(38,37)) as decimal(38,17)) from range(3)").show
The bug exists for Decimal that is stored using compact long only, it works fine with Decimal that uses scala.math.BigDecimal internally.
