[SPARK-21350] Fix the error message when the number of arguments is wrong when invoking a UDF

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.2, 2.1.1, 2.2.0
• Fix Version/s: 2.3.0
• Component/s: SQL
• Assignee: Xiao Li
• Reporter: Xiao Li
• Created: 09/Jul/17 03:53
• Updated: 11/Jul/17 03:20
• Resolved: 11/Jul/17 03:20

Description

Got a confusing error message when the number of arguments is wrong when invoking a UDF.

    val df = spark.emptyDataFrame
    spark.udf.register("foo", (_: String).length)
    df.selectExpr("foo(2, 3, 4)")

org.apache.spark.sql.UDFSuite$$anonfun$9$$anonfun$apply$mcV$sp$12 cannot be cast to scala.Function3
java.lang.ClassCastException: org.apache.spark.sql.UDFSuite$$anonfun$9$$anonfun$apply$mcV$sp$12 cannot be cast to scala.Function3
	at org.apache.spark.sql.catalyst.expressions.ScalaUDF.<init>(ScalaUDF.scala:109)

Issue Links

• links to: [Github] Pull Request #18574 (gatorsmile)