[FLINK-20989] Functions in ExplodeFunctionUtil should handle null data to avoid NPE

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.11.3
• Fix Version/s: 1.11.4
• Component/s: Table SQL / Planner
• Labels: pull-request-available
• Assignee: godfrey he
• Reporter: godfrey he
• Created: 15/Jan/21 07:51
• Updated: 28/May/21 07:09
• Resolved: 17/Jan/21 15:20

Description

The following test case will encounter NPE:

    val t = tEnv.fromValues(
      DataTypes.ROW(
        DataTypes.FIELD("a", DataTypes.INT()),
        DataTypes.FIELD("b", DataTypes.ARRAY(DataTypes.STRING()))
      ),
      row(1, Array("aa", "bb", "cc")),
      row(2, null),
      row(3, Array("dd"))
    )
    tEnv.registerTable("T", t)

    tEnv.executeSql("SELECT a, s FROM T, UNNEST(T.b) as A (s)").print()

Exception is

Caused by: java.lang.NullPointerException
	at scala.collection.mutable.ArrayOps$ofRef$.length$extension(ArrayOps.scala:192)
	at scala.collection.mutable.ArrayOps$ofRef.length(ArrayOps.scala:192)
	at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:32)
	at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186)
	at org.apache.flink.table.planner.plan.utils.ObjectExplodeTableFunc.eval(ExplodeFunctionUtil.scala:34)

The reason is functions in ExplodeFunctionUtil do not handle null data. Since 1.12, the bug is fixed, see https://issues.apache.org/jira/browse/FLINK-18528

Issue Links

• links to: GitHub Pull Request #14664