pentaho/pentaho-kettle · error · Rhino runtime error

Please provide a filename to the function call…

Error message

Please provide a filename to the function call loadFileContent.

What it means

loadFileContent reads a file's contents into a JS variable in the Modified Java Script Value step. The library throws this Rhino runtime error when the function is called with zero arguments, because a filename is mandatory to know which file to read.

Solutions

Pass the file path as the first argument: loadFileContent('/path/to/file')
Ensure the filename variable is non-empty before calling (guard with an if)
Check that the field feeding the argument is populated in the incoming rows
Prefer Kettle's Text File Input step for bulk file reads instead of per-row JS

Example fix

// before
var content = loadFileContent();
// after
var content = loadFileContent(filenameField);

Defensive patterns

Strategy: validation

Validate before calling

if (typeof filenameField === 'string' && filenameField.length > 0) { var content = loadFileContent(filenameField); } else { var content = null; }

Type guard

function hasFilename(v){ return typeof v === 'string' && v.trim().length > 0; }

Try / catch

try { var content = loadFileContent(filenameField); } catch (e) { throw new Error('loadFileContent needs a filename: ' + e.message); }

Prevention

Always pass a non-empty filename as the first argument
Validate the incoming field is populated before calling
Use dedicated input steps for heavy file reading rather than per-row JS
Handle null/undefined filename rows gracefully instead of letting the call collapse to zero args

When it happens

Trigger: loadFileContent() with an empty argument list — the switch case 0 immediately throws Context.reportRuntimeError; also occurs when the filename variable passed is dropped so the array is empty.

Common situations: Field variable undefined at runtime so the call collapses to no arguments; users forgetting to pass the path expecting a file-picker dialog; scripts copied without the filename argument.

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

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/7e431f3310713f02. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/scriptvalues_mod/ScriptValuesAddedFunctions.java:2792

  public static String initCap( Context actualContext, Scriptable actualObject, Object[] ArgList,
    Function FunctionContext ) {
    if ( ArgList.length == 1 ) {
      return Const.initCap( Context.toString( ArgList[0] ) );
    } else {
      throw Context.reportRuntimeError( "The function call initCap requires 1 argument." );

    }
  }

  public static Object loadFileContent( Context actualContext, Scriptable actualObject, Object[] ArgList,
    Function FunctionContext ) {
    Object oRC = new Object();
    try {

      switch ( ArgList.length ) {
        case 0:
          throw Context.reportRuntimeError( "Please provide a filename to the function call loadFileContent." );
        case 1:
          try {
            if ( isNull( ArgList ) ) {
              return null;
            } else if ( isUndefined( ArgList ) ) {
              return Context.getUndefinedValue();
            }
            // Returns file content
            oRC = new String( LoadFileInput.getFileBinaryContent( getBowl( actualObject ),
                                                                  Context.toString( ArgList[0] ) ) );
          } catch ( Exception e ) {
            throw Context
              .reportRuntimeError( "The function call loadFileContent throw an error : " + e.toString() );
          }
          break;
        case 2:
          try {
            if ( ArgList[0].equals( null ) ) {

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