mass action not passing identifiers

[matthbull]

Im not entirely sure if this is something Ive not done, or whether its something missing in the documentation.

When adding a massAction using a controller function, the key values are not passed through as per the documentation, its necessary to grab them out of the request manually.

  $massAction = new MassAction( 'Delete', 'MyBundle:Documents:massDelete', 'Are you sure?...' );
  $grid->addMassAction( $massAction );
 //...

controller

public function massDeleteAction($keys, $allKeys) {
    // ... do something with keys
}

This does not pass the keys through to the controller method.

public function massDeleteAction(Request $request) {
    $data = $request->request->all();
   // .. do something with the data
}

This is the only way I can get access to the form data. What am I doing wrong? While its no issue to do it this way, its not mentioned in the documentation that I have to, hence Im thinking Im wrong.

Symfony 2.7.6 thanks.