[FLINK-15452] Missing type coercion when generating code with ScalarFunctionCallGen

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 1.9.0
• Fix Version/s: 1.11.0
• Component/s: Table SQL / Planner
• Labels: pull-request-available
• External issue URL: https://issues.apache.org/jira/browse/FLINK-10965
• External issue ID: 10965
• Assignee: Unassigned
• Reporter: Peijian He
• Created: 02/Jan/20 02:41
• Updated: 30/Apr/20 13:53
• Resolved: 30/Apr/20 13:49

Description

I defined a UDF as follows:

class ScalarFunction1(val udfs: UDF1[Any, Any]) extends ScalarFunction {
  def eval(t1: Any): Any = {
    udfs.eval(t1)
  }

  override def open(context: FunctionContext): Unit = {
    udfs.open()
  }

  override def close(): Unit = {
    udfs.close()
  }

  override def getResultType(signature: Array[Class[_]]): typeinfo.TypeInformation[_] = {
    toDataType(udfs.getReturnType)
  }
}

 

An examples of the parameter udfs is as follows:

 

public class IsNumber extends UDF1<String, Boolean> {
    @Override
    public void open() {

    }

    @Override
    public void close() {

    }

    @Override
    public Boolean eval(String str) {
        for (int i = 0; i < str.length(); i++){
            if (!Character.isDigit(str.charAt(i))){
                return false;
            }
        }
        return true;
    }
}

 

In this case, function getResultType return Boolean, but I get error as follows:

Caused by: org.codehaus.commons.compiler.CompileException: Line 118, Column 10: Assignment conversion not possible from type "java.lang.Object" to type "java.lang.Boolean" at org.codehaus.janino.UnitCompiler.compileError(UnitCompiler.java:12124) at org.codehaus.janino.UnitCompiler.assignmentConversion(UnitCompiler.java:10975) at org.codehaus.janino.UnitCompiler.compile2(UnitCompiler.java:2578) at org.codehaus.janino.UnitCompiler.access$2700(UnitCompiler.java:215) at org.codehaus.janino.UnitCompiler$6.visitLocalVariableDeclarationStatement(UnitCompiler.java:1503) at org.codehaus.janino.UnitCompiler$6.visitLocalVariableDeclarationStatement(UnitCompiler.java:1487) at org.codehaus.janino.Java$LocalVariableDeclarationStatement.accept(Java.java:3511) at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:1487) at org.codehaus.janino.UnitCompiler.compileStatements(UnitCompiler.java:1567) at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:3388) at org.codehaus.janino.UnitCompiler.compileDeclaredMethods(UnitCompiler.java:1357) at org.codehaus.janino.UnitCompiler.compileDeclaredMethods(UnitCompiler.java:1330) at org.codehaus.janino.UnitCompiler.compile2(UnitCompiler.java:822) at org.codehaus.janino.UnitCompiler.compile2(UnitCompiler.java:432) at org.codehaus.janino.UnitCompiler.access$400(UnitCompiler.java:215) at org.codehaus.janino.UnitCompiler$2.visitPackageMemberClassDeclaration(UnitCompiler.java:411) at org.codehaus.janino.UnitCompiler$2.visitPackageMemberClassDeclaration(UnitCompiler.java:406) at org.codehaus.janino.Java$PackageMemberClassDeclaration.accept(Java.java:1414) at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:406) at org.codehaus.janino.UnitCompiler.compileUnit(UnitCompiler.java:378) at org.codehaus.janino.SimpleCompiler.cook(SimpleCompiler.java:237) at org.codehaus.janino.SimpleCompiler.compileToClassLoader(SimpleCompiler.java:465) at org.codehaus.janino.SimpleCompiler.cook(SimpleCompiler.java:216) at org.codehaus.janino.SimpleCompiler.cook(SimpleCompiler.java:207) at org.codehaus.commons.compiler.Cookable.cook(Cookable.java:80) at org.codehaus.commons.compiler.Cookable.cook(Cookable.java:75) at org.apache.flink.table.codegen.Compiler$class.compile(Compiler.scala:33) ... 10 more

 

Another case:

if I remove getResultType method, it cause an error when using nested udf as follows,

 nested UDF:

CastBoolToString(IsNumber(topic))

CastBoolToString required Boolean type parameter, but got Object type.

So caused error:

Caused by: org.codehaus.commons.compiler.CompileException: Line 118, Column 10: Assignment conversion not possible from type "java.lang.Object" to type "java.lang.Boolean"
	at org.codehaus.janino.UnitCompiler.compileError(UnitCompiler.java:12124)
	at org.codehaus.janino.UnitCompiler.assignmentConversion(UnitCompiler.java:10975)
	at org.codehaus.janino.UnitCompiler.compile2(UnitCompiler.java:2578)
	at org.codehaus.janino.UnitCompiler.access$2700(UnitCompiler.java:215)
	at org.codehaus.janino.UnitCompiler$6.visitLocalVariableDeclarationStatement(UnitCompiler.java:1503)
	at org.codehaus.janino.UnitCompiler$6.visitLocalVariableDeclarationStatement(UnitCompiler.java:1487)
	at org.codehaus.janino.Java$LocalVariableDeclarationStatement.accept(Java.java:3511)
	at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:1487)
	at org.codehaus.janino.UnitCompiler.compileStatements(UnitCompiler.java:1567)
	at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:3388)
	at org.codehaus.janino.UnitCompiler.compileDeclaredMethods(UnitCompiler.java:1357)
	at org.codehaus.janino.UnitCompiler.compileDeclaredMethods(UnitCompiler.java:1330)
	at org.codehaus.janino.UnitCompiler.compile2(UnitCompiler.java:822)
	at org.codehaus.janino.UnitCompiler.compile2(UnitCompiler.java:432)
	at org.codehaus.janino.UnitCompiler.access$400(UnitCompiler.java:215)
	at org.codehaus.janino.UnitCompiler$2.visitPackageMemberClassDeclaration(UnitCompiler.java:411)
	at org.codehaus.janino.UnitCompiler$2.visitPackageMemberClassDeclaration(UnitCompiler.java:406)
	at org.codehaus.janino.Java$PackageMemberClassDeclaration.accept(Java.java:1414)
	at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:406)
	at org.codehaus.janino.UnitCompiler.compileUnit(UnitCompiler.java:378)
	at org.codehaus.janino.SimpleCompiler.cook(SimpleCompiler.java:237)
	at org.codehaus.janino.SimpleCompiler.compileToClassLoader(SimpleCompiler.java:465)
	at org.codehaus.janino.SimpleCompiler.cook(SimpleCompiler.java:216)
	at org.codehaus.janino.SimpleCompiler.cook(SimpleCompiler.java:207)
	at org.codehaus.commons.compiler.Cookable.cook(Cookable.java:80)
	at org.codehaus.commons.compiler.Cookable.cook(Cookable.java:75)
	at org.apache.flink.table.codegen.Compiler$class.compile(Compiler.scala:33)
	... 10 more

 

 

I found that the following code in org.apache.flink.table.codegen.calls.ScalarFunctionCallGen caused the error：

val functionCallCode =
  s"""
    |${parameters.map(_.code).mkString("\n")}
    |$resultTypeTerm $resultTerm = $functionReference.eval(
    |  ${parameters.map(_.resultTerm).mkString(", ")});
    |""".stripMargin

if return type of $functionReference.eval is Object and $resultTypeTerm is Boolean, above error occurs.

So add type coercion to solve the problem.

 

Issue Links

• links to: GitHub Pull Request #10739