pentaho/pentaho-kettle · error · RuntimeException

The function call createRowCopy requires a single arguments…

Error message

The function call createRowCopy requires a single arguments : the new size of the row

What it means

Argument-count guard for the createRowCopy added function in ScriptAddedFunctions. createRowCopy requires exactly one argument — the new size of the row; any other argument count throws this RuntimeException.

Solutions

1. Call createRowCopy with exactly one integer argument: the new row size.
2. Populate the extra slots on the returned copy afterwards (e.g. newRow[oldSize] = value).
3. Search the script for createRowCopy( and correct the argument list.

Example fix

// before
var newRow = createRowCopy(3, firstName);
// after
var newRow = createRowCopy(3);
newRow[2] = firstName;

if (arguments.length !== 1 || typeof arguments[0] !== 'number') throw new Error('createRowCopy requires exactly one integer: the new row size');

try { var r = createRowCopy(2); } catch (e) { if (String(e).indexOf('requires a single arguments') !== -1) { /* correct the call site to one argument */ } throw e; }

When it happens

Trigger: Calling createRowCopy() with no arguments, or with two or more arguments, e.g. createRowCopy(size, extra) or createRowCopy(newSize, newData).

Common situations: Author assuming createRowCopy accepts the new field values along with the size (it does not), or translating older Kettle JavaScript samples incorrectly.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• The function call getInputRowMeta doesn't require arguments.
• Unable to create a row copy:
• Unable to get the input row metadata because of an error:
• Unable to pass the new row to the next step(s) because of…
• Calculator.ErrorInStepRunning

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/b4a267fded8234ac. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/script/ScriptAddedFunctions.java:1916

    }
  }

  // Return the input row metadata
  public static Object[] createRowCopy( ScriptEngine actualContext, Bindings actualObject, Object[] ArgList,
    Object FunctionContext ) {
    if ( ArgList.length == 1 ) {
      try {
        int newSize = (int) Math.round( (Double) ArgList[0] );

        Object scmO = actualObject.get( "row" );
        Object[] row = (Object[]) scmO; // TODO AKRETION ensure

        return RowDataUtil.createResizedCopy( row, newSize );
      } catch ( Exception e ) {
        throw new RuntimeException( "Unable to create a row copy: " + Const.CR + e.toString() );
      }
    } else {
      throw new RuntimeException(
        "The function call createRowCopy requires a single arguments : the new size of the row" );
    }
  }

  // put a row out to the next steps...
  //
  public static void putRow( ScriptEngine actualContext, Bindings actualObject, Object[] ArgList,
    Object FunctionContext ) {
    if ( ArgList.length == 1 ) {
      try {
        Object[] newRow = (Object[]) ArgList[0];

        Object scmO = actualObject.get( "_step_" );
        try {
          Script step = (Script) scmO;
          step.putRow( step.getOutputRowMeta(), newRow );
        } catch ( Exception e ) {
          ScriptDummy step = (ScriptDummy) scmO;

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