Johan Nyström-Persson created SPARK-38042:
---------------------------------------------

             Summary: Encoder cannot be found when a tuple component is a type 
alias for an Array
                 Key: SPARK-38042
                 URL: https://issues.apache.org/jira/browse/SPARK-38042
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 3.2.0, 3.1.2
            Reporter: Johan Nyström-Persson


ScalaReflection.dataTypeFor fails when Array[T] has been aliased for some T, 
and then the alias is being used as a component of e.g. a product.

Minimal example, tested in version 3.1.2:
{code:java}
type Data = Array[Long]
val xs:List[(Data,Int)] = List((Array(1),1), (Array(2),2))
sc.parallelize(xs).toDF("a", "b"){code}
This gives the following exception:
{code:java}
scala.MatchError: Data (of class 
scala.reflect.internal.Types$AliasNoArgsTypeRef) 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.$anonfun$dataTypeFor$1(ScalaReflection.scala:104)
 
 at 
scala.reflect.internal.tpe.TypeConstraints$UndoLog.undo(TypeConstraints.scala:69)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection.cleanUpReflectionObjects(ScalaReflection.scala:904)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection.cleanUpReflectionObjects$(ScalaReflection.scala:903)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.cleanUpReflectionObjects(ScalaReflection.scala:49)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.dataTypeFor(ScalaReflection.scala:88)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.$anonfun$serializerFor$6(ScalaReflection.scala:573)
 
 at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:238) 
 at scala.collection.immutable.List.foreach(List.scala:392) 
 at scala.collection.TraversableLike.map(TraversableLike.scala:238) 
 at scala.collection.TraversableLike.map$(TraversableLike.scala:231) 
 at scala.collection.immutable.List.map(List.scala:298) 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.$anonfun$serializerFor$1(ScalaReflection.scala:562)
 
 at 
scala.reflect.internal.tpe.TypeConstraints$UndoLog.undo(TypeConstraints.scala:69)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection.cleanUpReflectionObjects(ScalaReflection.scala:904)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection.cleanUpReflectionObjects$(ScalaReflection.scala:903)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.cleanUpReflectionObjects(ScalaReflection.scala:49)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.serializerFor(ScalaReflection.scala:432)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.$anonfun$serializerForType$1(ScalaReflection.scala:421)
 
 at 
scala.reflect.internal.tpe.TypeConstraints$UndoLog.undo(TypeConstraints.scala:69)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection.cleanUpReflectionObjects(ScalaReflection.scala:904)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection.cleanUpReflectionObjects$(ScalaReflection.scala:903)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.cleanUpReflectionObjects(ScalaReflection.scala:49)
 
 at 
org.apache.spark.sql.catalyst.ScalaReflection$.serializerForType(ScalaReflection.scala:413)
 
 at 
org.apache.spark.sql.catalyst.encoders.ExpressionEncoder$.apply(ExpressionEncoder.scala:55)
 
 at org.apache.spark.sql.Encoders$.product(Encoders.scala:285) 
 at 
org.apache.spark.sql.LowPrioritySQLImplicits.newProductEncoder(SQLImplicits.scala:251)
 
 at 
org.apache.spark.sql.LowPrioritySQLImplicits.newProductEncoder$(SQLImplicits.scala:251)
 
 at org.apache.spark.sql.SQLImplicits.newProductEncoder(SQLImplicits.scala:32) 
 ... 48 elided{code}
{{{}{}}}Off the top of my head, I think this could be fixed by changing e.g.{{{}
{}}}

 
{code:java}
getClassNameFromType(tpe) to 
getClassNameFromType(tpe.dealias)
{code}
 

in ScalaReflection.dataTypeFor. I will try to test that and submit a pull 
request shortly.

 

 



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