Ctools form wizard - modifying step order, removing steps

Thanks for such a quick response. I've taken your suggestion and changed my application so that the form is built from the object cache. That part works.

However, I'm having difficultly determining exactly how the form_info should be modified in order to skip or remove steps. I saw #1570628: Documentation: How to skip one step in wizard programatically?, which suggests that modifying $form_state['clicked_button']['#next'] would correctly set the redirect for the next step, but it doesn't seem to work for me. A few other variables look tempting:

  $form_state['clicked_button']['#next']
  $form_state['triggering_element']['#next']
  $form_state['buttons'][0]['#next']
  $form_state['redirect'][0]

Anyway, the best way to communicate this may be to simply show you the code. No one likes looking through huge code blocks... but these should be fairly straightforward implementations of the form wizard.

Build form using data from object cache:

/**
 * Create callback for standard ctools registration wizard.
 */
function ysl_registration_multistep_registration_form($step = 'register') {
  ctools_include('wizard');
  ctools_include('object-cache');
  module_load_include('inc', 'ysl_registration', 'ysl_registration.ctools_wizard');

  // Grab most recent version of cached ctools object.
  $ctools_object = ysl_registration_get_ctools_cache('multistep_registration');

  // Define form_info defaults.
  if (empty($ctools_object->form_info)) {
    $ctools_object->form_info = array(
      'id' => 'multistep_registration',
      'path' => "user/register/%step",
      'show trail' => TRUE,
      'show back' => FALSE,
      'show return' => FALSE,
      'next callback' => 'ysl_registration_multistep_registration_next',
      'finish callback' => 'ysl_registration_multistep_registration_finish',
      'return callback' => 'ysl_registration_multistep_registration_finish',
      'cancel callback' => 'ysl_registration_multistep_registration_cancel',
      'order' => array(
        'register' => t('Register'),
        'location' => t('Set your location'),
        'friends' => t('Find your friends'),
        'groups' => t('Connect'),
      ),
      'forms' => array(
        'register' => array(
          'form id' => 'user_register_form',
        ),
        'location' => array(
          'form id' => 'ysl_registration_location_form',
          'include' => drupal_get_path('module', 'ysl_registration') . '/ysl_registration_location_form.inc',
        ),      
        'friends' => array(
          'form id' => 'ysl_registration_friends_form',
          'include' => drupal_get_path('module', 'ysl_registration') . '/ysl_registration_friends_form.inc',
        ),
        'groups' => array(
          // The title for this is set in preprocess-page.inc
          'form id' => 'ysl_registration_group_info_form',
          'include' => drupal_get_path('module', 'ysl_registration') . '/ysl_registration_groups_form.inc',
        ),
      ),
    );
  }
  $form_state['ctools_object'] = $ctools_object; 
  $output = ctools_wizard_multistep_form($ctools_object ->form_info, $step, $form_state);

  return $output;
}

In my custom submit handler for step 1 (user_register_form), modify the form_info in the object cache:

/**
 * Submit callback for user_register_form.
 */
function ysl_registration_user_register_form_submit($form, &$form_state) {
  // Add postal code to signup object. Object is cached via ctools wizard.
  $form_state['ctools_object']->data['postal_code'] = $form_state['values']['postal_code'];
  
  // We're going to remove the 'location' step.
  unset($form_state['ctools_object']->form_info['order']['location']);
  unset($form_state['ctools_object']->form_info['forms']['location']);
  
  // Determine what the next step should be.
  $steps = $form_state['ctools_object']->form_info['order'];
  $current = $form_state['step'];
  while (key($steps) !== $current) next($steps);
  next($steps);
  $next = key($steps);

  // Set the next step.
  $form_state['clicked_button']['#next'] = $next;
  $form_state['triggering_element']['#next'] = $next;
  $form_state['next'] = $next;
}

A few utility functions to handle the object cache:

/**
 * Callback generated when the 'next' button is clicked.
 *
 * All we do here is store the cache.
 */
function ysl_registration_multistep_registration_next(&$form_state) {
  // Update the cache with changes.
  ysl_registration_set_ctools_cache('multistep_registration', $form_state['ctools_object']);
}

/**
 * Get the cached changes to a given task handler.
 */
function ysl_registration_get_ctools_cache($name) {
  ctools_include('object-cache');
  $cache = ctools_object_cache_get('ysl_registration', $name);
  if (!$cache) {
    $cache = new stdClass();
    $cache->locked = ctools_object_cache_test('ysl_registration', $name);
  }
  return $cache;
}

/**
 * Store changes to a task handler in the object cache.
 */
function ysl_registration_set_ctools_cache($name, $data) {
  ctools_include('object-cache');
  $cache = ctools_object_cache_set('ysl_registration', $name, $data);
}

/**
 * Remove an item from the object cache.
 */
function ysl_registration_clear_ctools_cache($name) {
  ctools_include('object-cache');
  ctools_object_cache_clear('ysl_registration', $name);
}

Unfortunately, the 'location' step is still set as step 2 after this modification. Unsetting the 'order' key merely removes the step from the form trail, and removing the 'forms' key will result in a blank page. Regardless, I am still redirected to the original step 2 url.

Thanks in advance!

Managed to figure this out! The issue was that the form had multiple submit handlers, and they weren't being called in the right order. After defining the correct order, everything seems to work.

    // It is very important that these submit handlers fire in the right order!
    $form['#submit'] = array(
      'user_register_submit',
      'ysl_registration_user_register_form_submit',
      'ctools_wizard_submit',
    );