[GitHub] [spark] gemelen commented on a change in pull request #29995: [WIP][SPARK-33080][BUILD] Replace fatal warnings snippet

[GitBox <gi...@apache.org>]

gemelen commented on a change in pull request #29995:
URL: https://github.com/apache/spark/pull/29995#discussion_r502900514



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File path: sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/UnsafeArraySuite.scala
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@@ -72,9 +72,9 @@ class UnsafeArraySuite extends SparkFunSuite {
     arrayData
   }
 
-  private def toUnsafeArray[T : TypeTag](array: Array[T]): ArrayData = {
+  private def toUnsafeArray[T: Manifest](array: Array[T]): ArrayData = {
     val converted = ExpressionEncoder[Array[T]].createSerializer().apply(array).getArray(0)
-    assert(converted.isInstanceOf[T])
+    assert(manifest[T].runtimeClass.isInstance(converted))

Review comment:
       I've looked more at this assert and it seems to me that it should never pass, cause `ArrayData` does not have "is-a" relation with `T` type (`ArrayData` even is not a wrapper to `Array[T]` which also has no "is-a" relation with `T` according to Scala types).
   
   Previously, it caused warnings
   ```
   [warn] /tmp/spark/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/UnsafeArraySuite.scala:77:34: abstract type T is unchecked since it is eliminated by erasure
   [warn] /tmp/spark/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/UnsafeArraySuite.scala:77:11: abstract type T is unchecked since it is eliminated by erasure
   ```
   but they were not enforced by custom warning processor.
   
   @srowen @hvanhovell @dongjoon-hyun is my understanding is correct here?




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