pentaho/pentaho-kettle · error · RuntimeException

The function call rtrim requires 1 argument.

Error message

The function call rtrim requires 1 argument.

What it means

rtrim strips trailing whitespace from a string and requires exactly one argument. When ArgList.length != 1 it throws this RuntimeException. Symmetric to ltrim's guard, this check runs before any trimming work.

Solutions

1. Call with exactly one argument: rtrim(str).
2. Remove extra arguments; for custom trailing characters use str.replace(/\s+$/, '') or a targeted regex in JavaScript.
3. Convert non-string values with String(value) before calling to also avoid the related 'not valid' wrapper error.

Example fix

// before
var trimmed = rtrim(name, '\t');
// after
var trimmed = rtrim(name);

if (arguments.length !== 1 || typeof str !== 'string') {
  throw new Error('rtrim requires exactly one string argument');
}
var trimmed = rtrim(str);

function isStringArg(v) { return typeof v === 'string' || v instanceof String; }

try {
  var trimmed = rtrim(str);
} catch (e) {
  if (String(e.message).indexOf('requires 1 argument') !== -1) {
    throw new Error('Call rtrim with exactly one argument');
  } else { throw e; }
}

When it happens

Trigger: Calling rtrim() with no arguments, or rtrim(str, chars) passing a character-set second argument that this API does not accept.

Common situations: Porting code from rtrim variants that take a character list; forgetting to pass the field because another function bound it implicitly.

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 initCap requires 1 argument.
• The function call ltrim requires 1 argument.
• The function call removeDigits requires 1 argument.
• Please provide a valid Char to the fillString
• The function call date2str requires 1, 2, 3, or 4 arguments.

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/beeab079314928bb. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/script/ScriptAddedFunctions.java:770

      }
    } 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 ) {
      throw new RuntimeException( "The function call rtrim is not valid : " + e.getMessage() );
    }
  }

  public static String lpad( ScriptEngine actualContext, Bindings actualObject, Object[] ArgList,
    Object FunctionContext ) {

    // (String valueToPad, String filler, int size) {
    try {
      if ( ArgList.length == 3 ) {
        if ( isNull( ArgList, new int[] { 0, 1, 2 } ) ) {
          return null;
        } else if ( isUndefined( ArgList, new int[] { 0, 1, 2 } ) ) {
          return (String) undefinedValue;
        }
        String valueToPad = (String) ArgList[0];

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