pentaho/pentaho-kettle · error · RuntimeException

The function call ltrim is not valid :

Error message

The function call ltrim is not valid : 

What it means

ltrim wraps all processing in a try/catch; any exception (most commonly a ClassCastException when ArgList[0] is not a String) is rethrown as RuntimeException('The function call ltrim is not valid : ' + e.getMessage()). Unlike the other wrappers it uses getMessage(), which is often null, yielding a message that ends with a dangling colon and no cause.

Solutions

1. Convert the argument to a string first: ltrim(String(value)).
2. Because getMessage() may be null, log e in the script or test the argument type before calling to get a clearer failure.
3. Guard null/undefined with isUndefined(ArgList[0]) before calling ltrim.
4. Coerce numeric fields with str2num/str functions or JavaScript String() before trimming.

Example fix

// before
var trimmed = ltrim(idField); // idField is a number
// after
var trimmed = ltrim(String(idField));

if (str === null || str === undefined) return str;
if (typeof str !== 'string') str = String(str);
var trimmed = ltrim(str);

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

try {
  var trimmed = ltrim(str);
} catch (e) {
  // getMessage() may be null; wrap with argument info
  throw new Error('ltrim failed on value: ' + str + ' (' + e + ')');
}

When it happens

Trigger: Calling ltrim with a non-string first argument (number, date, null) so the (String) cast or replaceAll call throws inside the try block.

Common situations: Passing numeric stream fields directly without String() conversion; passing null dates; empty bindings where the variable is undefined (use isUndefined first).

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Could not convert to the given local format.
• Please provide a filename to the function call…
• Please provide a valid Char to the fillString
• The function call date2str requires 1, 2, 3, or 4 arguments.
• The function call dateAdd requires 3 arguments.

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/2a39101cf31365c2. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/script/ScriptAddedFunctions.java:754

    return Boolean.valueOf( bRC );
  }

  public static String ltrim( ScriptEngine actualContext, Bindings actualObject, Object[] ArgList,
    Object FunctionContext ) {
    try {
      if ( ArgList.length == 1 ) {
        if ( isNull( ArgList[0] ) ) {
          return null;
        } else if ( isUndefined( ArgList[0] ) ) {
          return (String) undefinedValue;
        }
        String strValueToTrim = (String) ArgList[0];
        return strValueToTrim.replaceAll( "^\\s+", "" );
      } else {
        throw new RuntimeException( "The function call ltrim requires 1 argument." );
      }
    } catch ( Exception e ) {
      throw new RuntimeException( "The function call ltrim is not valid : " + e.getMessage() );
    }
  }

  public static String rtrim( ScriptEngine actualContext, Bindings actualObject, Object[] ArgList,
    Object FunctionContext ) {
    try {
      if ( ArgList.length == 1 ) {
        if ( isNull( ArgList[0] ) ) {
          return null;
        } else if ( isUndefined( ArgList[0] ) ) {
          return (String) undefinedValue;
        }
        String strValueToTrim = (String) ArgList[0];
        return strValueToTrim.replaceAll( "\\s+$", "" );
      } else {
        throw new RuntimeException( "The function call rtrim requires 1 argument." );
      }
    } catch ( Exception e ) {

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