[jira] [Created] (SPARK-40963) containsNull in array type attributes is not updated from child output

["Bruce Robbins (Jira)" <ji...@apache.org>]

Bruce Robbins created SPARK-40963:
-------------------------------------

             Summary: containsNull in array type attributes is not updated from child output
                 Key: SPARK-40963
                 URL: https://issues.apache.org/jira/browse/SPARK-40963
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 3.4.0
            Reporter: Bruce Robbins


Example:
{noformat}
select c1, explode(c4) as c5 from (
  select c1, array(c3) as c4 from (
    select c1, explode_outer(c2) as c3
    from values
    (1, array(1, 2)),
    (2, array(2, 3)),
    (3, null)
    as data(c1, c2)
  )
);

+---+---+
|c1 |c5 |
+---+---+
|1  |1  |
|1  |2  |
|2  |2  |
|2  |3  |
|3  |0  |
+---+---+
{noformat}
In the last row, {{c5}} is 0, but should be {{NULL}}.

At the time {{ResolveGenerate.makeGeneratorOutput}} is called for {{explode(c4)}}, {{c3}} has nullable set to false, so {{c4}}'s data type has {{containsNull}} also set to false. Later, {{c3}}'s nullability is updated and c4's data type reports containsNull = true, but two things go wrong:

* The {{containsNull}} setting for {{c4}} is not propogated to parent operators (so the attribute {{c4}} in {{explode(c4)}} still has containsNull = false)
* Even if it were propogated, {{generatorOutput}} for {{explode(c4)}} is already determined and won't be recalculated.

Another example:
{noformat}
select c1, inline_outer(c4) from (
  select c1, array(c3) as c4 from (
    select c1, explode_outer(c2) as c3
    from values
    (1, array(named_struct('a', 1, 'b', 2))),
    (2, array(named_struct('a', 3, 'b', 4), named_struct('a', 5, 'b', 6))),
    (3, null)
    as data(c1, c2)
  )
);

22/10/27 11:53:20 ERROR Executor: Exception in task 1.0 in stage 1.0 (TID 2)
java.lang.NullPointerException
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.generate_doConsume_1$(Unknown Source)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.generate_doConsume_0$(Unknown Source)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.processNext(Unknown Source)
	at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
	at org.apache.spark.sql.execution.WholeStageCodegenExec$$anon$1.hasNext(WholeStageCodegenExec.scala:760)
	at org.apache.spark.sql.execution.SparkPlan.$anonfun$getByteArrayRdd$1(SparkPlan.scala:364)
	
-
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{noformat}




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