What causes "vfs.provider/create-folder-not-supported.error" in pentaho/pentaho-kettle?

Create parent prefixes first, one level at a time, before creating the deepest folder

pentaho/pentaho-kettle · error · FileSystemException

vfs.provider/create-folder-not-supported.error

vfs.provider/create-folder-not-supported.error

Error message

vfs.provider/create-folder-not-supported.error

What it means

Thrown by S3CommonFileObject.doCreateFolder() when the file object is not a folder-capable type (the 'isFolderCreatable' style condition fails), so no S3 folder marker can be written. It indicates the requested folder-creation operation is not supported for this object.

Solutions

Create parent prefixes first, one level at a time, before creating the deepest folder
Check the condition guarding doCreateFolder to see why the object was deemed non-folder-creatable
Write files under the desired prefix instead — S3 implicitly treats prefixes as folders
Avoid using a generic VFS createFolder on S3 objects that represent existing files

Example fix

// before
FileObject folder = fsManager.resolveFile( "s3://bucket/a/b/c/" );
folder.createFolder();
// after
FileObject parent = fsManager.resolveFile( "s3://bucket/a/" );
parent.createFolder();
fsManager.resolveFile( "s3://bucket/a/b/" ).createFolder();
fsManager.resolveFile( "s3://bucket/a/b/c/" ).createFolder();

Defensive patterns

Strategy: validation

Validate before calling

// create parent levels first, then leaf
FileObject parent = fsManager.resolveFile( "s3://bucket/some/existing/" );
if ( !parent.exists() ) {
  throw new IllegalStateException( "parent prefix must exist: " + parent.getName().getURI() );
}

Try / catch

try {
  folder.createFolder();
} catch ( FileSystemException e ) {
  if ( "vfs.provider/create-folder-not-supported.error".equals( e.getMessage() ) ) {
    // fall back to writing a marker object or creating parents individually
  }
  throw e;
}

Prevention

Create parent prefixes level by level before creating nested folders
Never call createFolder() on an object that resolves to an existing file key
Check the VFS scheme supports folder semantics before using generic createFolder
Rely on implicit S3 prefix semantics when deep nesting is needed

When it happens

Trigger: Calling createFolder() on an S3 VFS object whose type/scheme does not permit creating the zero-byte '/'-suffixed marker object (e.g. creating nested folders under a non-existent parent path, or a non-s3 file object).

Common situations: Trying to create deeply nested folders where parent prefixes don't exist; calling folder creation on a file-type S3 object; using the VFS manager on a scheme where folder creation isn't implemented.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/3a5d7b32c55da9c9. Report an issue: GitHub.

Appendix: source

Thrown at plugins/s3-vfs/core/src/main/java/org/pentaho/s3common/S3CommonFileObject.java:513

      // create meta-data for your folder and set content-length to 0
      ObjectMetadata metadata = new ObjectMetadata();
      metadata.setContentLength( 0 );
      metadata.setContentType( "binary/octet-stream" );

      // create empty content
      InputStream emptyContent = new ByteArrayInputStream( new byte[ 0 ] );

      // create a PutObjectRequest passing the folder name suffixed by /
      PutObjectRequest putObjectRequest = createPutObjectRequest( bucketName, key + DELIMITER, emptyContent, metadata );

      // send request to S3 to create folder
      try {
        fileSystem.getS3Client().putObject( putObjectRequest );
      } catch ( AmazonS3Exception e ) {
        throw new FileSystemException( "vfs.provider.local/create-folder.error", this, e );
      }
    } else {
      throw new FileSystemException( "vfs.provider/create-folder-not-supported.error" );
    }
  }


  protected PutObjectRequest createPutObjectRequest( String bucketName, String key, InputStream inputStream,
                                                     ObjectMetadata objectMetadata ) {
    return new PutObjectRequest( bucketName, key, inputStream, objectMetadata );
  }

  @Override
  protected void doRename( FileObject newFile ) throws Exception {
    // no folder renames on S3
    if ( getType().equals( FileType.FOLDER ) ) {
      logger.debug( "recursively moving folder [{}] -> [{}]", this.getPublicURIString(), newFile.getPublicURIString() );
      doFolderMove( this, newFile );
      return;
    }

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