What causes "The function call deleteFile is not valid." in pentaho/pentaho-kettle?

Wrap the raw RuntimeException in a try-catch in your script and log the underlying cause — this throw discards the original IOException, so reproduce the path with KettleVFS directly for a real message.

pentaho/pentaho-kettle · error · RuntimeException

The function call deleteFile is not valid.

Error message

The function call deleteFile is not valid.

What it means

Inside deleteFile(), any IOException raised while resolving or inspecting the file object is swallowed and replaced with the generic message 'The function call deleteFile is not valid.' This indicates the VFS/IO layer failed (bad URI, unsupported scheme, connection error) rather than the file simply not existing.

Solutions

Wrap the raw RuntimeException in a try-catch in your script and log the underlying cause — this throw discards the original IOException, so reproduce the path with KettleVFS directly for a real message.
Validate the path is a well-formed VFS URI (correct scheme, forward slashes, no illegal characters) before calling.
Test the same path with a 'Text File Input' step or KettleVFS in a small script to see the true IOException.
Prefer java.io.File/java.nio.file.Files for plain local paths instead of deleteFile() to get clearer errors.

Example fix

// before
deleteFile('C:\\data\\out.txt'); // backslashes break VFS URI
// after
deleteFile('file:///C:/data/out.txt');

Defensive patterns

Strategy: type-guard

Validate before calling

// reject paths VFS cannot parse before calling
if (!/^[a-z]+:\/\//.test(path) && path.indexOf('\\') >= 0) { throw new Error('normalize path first'); }

Type guard

function isVfsUri(p) { return typeof p === 'string' && (/^[a-z]+:\/\//.test(p) || p.startsWith('/')); }

Try / catch

try { deleteFile(path); } catch (e) { // message hides the real IOException; retry path via java.io.File to diagnose
  var f = new java.io.File(path); if (!f.delete()) throw new Error('delete failed: ' + path); }

Prevention

Use forward slashes and proper schemes in paths
Validate URIs before calling VFS-backed helpers
For local files prefer java.nio APIs with clearer errors

When it happens

Trigger: Calling deleteFile() with a malformed VFS URI or unsupported scheme (the KettleVFS.getFileObject call throws IOException), or an IO error while calling exists()/type checks.

Common situations: Passing a Windows path with backslashes or drive letters that VFS cannot parse; using schemes like sftp:/ with missing/invalid connection config; typos in the URI (e.g. 'htp://'); special characters in the filename that break URI parsing.

Understand the failure class

Background: "open() failed", "failed to open file", "cannot create file" — what a file open error means and how to fix it — this error's family across 42 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/d75955437f8a6f05. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/script/ScriptAddedFunctions.java:1970

        // Object act = actualObject.get("_step_", actualObject);
        // ScriptValuesMod act = (ScriptValuesMod)Context.toType(scm_delete, ScriptValuesMod.class);

        FileObject fileObject = null;

        try {
          fileObject = KettleVFS.getInstance( bowl ).getFileObject( (String) ArgList[0] );
          if ( fileObject.exists() ) {
            if ( fileObject.getType() == FileType.FILE ) {
              if ( !fileObject.delete() ) {
                throw new RuntimeException( "We can not delete file [" + (String) ArgList[0] + "]!" );
              }
            }

          } else {
            throw new RuntimeException( "file [" + ArgList[0] + "] can not be found!" );
          }
        } catch ( IOException e ) {
          throw new RuntimeException( "The function call deleteFile is not valid." );
        } finally {
          if ( fileObject != null ) {
            try {
              fileObject.close();
            } catch ( Exception e ) {
              // Ignore errors
            }
          }
        }

      } else {
        throw new RuntimeException( "The function call deleteFile is not valid." );
      }
    } catch ( Exception e ) {
      throw new RuntimeException( e.toString() );
    }
  }

View on GitHub (pinned to f3058517a1)