Conditional fields can cause form to submit unexpectedly

So the last page would contain nothing at all but a submit button? I think ending the form immediately *is* the intended behavior. If you want to have a confirmation page before the form is completed, you can add another page at the end of the form that exists regardless of the conditionals.

But we run into quite a few problems with the approach, we don't know if the next page is going to be required or not, especially since conditionals from earlier pages could determine if the next pages are necessary. We'd have to re-implement the entire conditional system for all pages in JavaScript just to change the button label. I'm not sure the overhead here is feasible.

This whole thing is going to get a lot worse when #258696: Multipage form - Page n of n (progress or percentage complete) is added. Considering you may have a 4 page form but 2 of them may get skipped, it's not going to help much what the label is if the progress bar tells you you're on step 2 of 4 but then it suddenly submits.

I think generally the easiest and most common solution to this problem is having a confirmation/summary page (#435232: Summary/review/preview page before final submission in multistep forms). It's not a problem suddenly skipping steps as long as there is some final warning before the form is completely submitted.

So is there a permanent solution for this behaviour of webform. Need help...

I think the right fix for this is to force a preview when this situation occurs. I'm investigating to see if this can be implemented reasonably. In this way, at least the unexpected page is a standard webform page.

I have a rather big patch to solve the issues around navigating conditional pages. The theory of operation is:

1) Rather than checking the node's webform['preview'], the form stores whether a preview page should be displayed.
2) Rather than iterating over the actual components and trying to handle all the special cases of preview (regular or forced) and backing up onto a hidden page 1, bogus faux components are added before and after the actual components. The regularizes the loop, treating the special cases similarly to regular components.

I have tested this with hidden pages as the first, a middle, and the last page. I have tested with with and without preview. I used the progress bar to help see where webform thinks it is. Still, this should receive wider testing before a stable release.

Committed to 7.x-4.x and 8.x.

Hello Dan,

i had to comment out 3 Lines from your Patch because a Multistep Webform (multiple Pages) always showed up "Preview" when the user entered the last step-page even though preview was deactivatet in the webforms config.

/**
 * Handle the processing of pages and conditional logic.
 */
function webform_client_form_pages($form, &$form_state) {
  $node = node_load($form_state['values']['details']['nid']);

  // Multistep forms may not have any components on the first page.
  if (!isset($form_state['values']['submitted'])) {
    $form_state['values']['submitted'] = array();
  }

  // Move special settings to storage.
  if (isset($form_state['webform']['component_tree'])) {
    $form_state['storage']['component_tree'] = $form_state['webform']['component_tree'];
    $form_state['storage']['page_count'] = $form_state['webform']['page_count'];
    $form_state['storage']['page_num'] = $form_state['webform']['page_num'];
    $form_state['storage']['preview'] = $form_state['webform']['preview'];
  }

  // Flatten trees within the submission.
  $form_state['values']['submitted'] = _webform_client_form_submit_flatten($node, $form_state['values']['submitted']);

  // Perform post processing by components.
  _webform_client_form_submit_process($node, $form_state['values']['submitted']);

  // Assume the form is completed unless the page logic says otherwise.
  $form_state['webform_completed'] = TRUE;

  // Check for a multi-page form that is not yet complete.
  $submit_op = !empty($form['actions']['submit']['#value']) ? $form['actions']['submit']['#value'] : t('Submit');
  $draft_op = !empty($form['actions']['draft']['#value']) ? $form['actions']['draft']['#value'] : t('Save Draft');
  if (!in_array($form_state['values']['op'], array($submit_op, $draft_op, '__AUTOSAVE__'))) {
    // Store values from the current page in the form state storage.
    if (is_array($form_state['values']['submitted'])) {
      foreach ($form_state['values']['submitted'] as $key => $val) {
        $form_state['storage']['submitted'][$key] = $val;
      }
    }

    // Update form state values with those from storage.
    if (isset($form_state['storage']['submitted'])) {
      foreach ($form_state['storage']['submitted'] as $key => $val) {
        $form_state['values']['submitted'][$key] = $val;
      }
    }

    // Set the page number.
    if (!isset($form_state['storage']['page_num'])) {
      $form_state['storage']['page_num'] = 1;
    }
    if (end($form_state['clicked_button']['#parents']) == 'next') {
      $forward = 1;
    }
    elseif (end($form_state['clicked_button']['#parents']) == 'previous') {
      $forward = 0;
    }
    $current_page = $form_state['storage']['page_num'];

    if (isset($forward)) {
      // Find the
      //    1) previous/next non-empty page, or
      //    2) the preview page, or
      //    3) the preview page, forcing its display if the form would unexpectedly submit, or
      //    4) page 1 even if empty, if no other previous page would be shown
      $preview_page_num = $form_state['storage']['page_count'] + (int)!$form_state['webform']['preview'];
      $page_zero = array(
        array(
          'type' => 'faux',
          'page_num' => 0,
        ),
        array(
          'type' => 'pagebreak',
          'page_num' => 1,
        ),
      );
      $page_preview = array(
        array(
          'type' => 'pagebreak',
          'page_num' => $preview_page_num,
        ),
         array(
          'type' => 'faux',
          'page_num' => $preview_page_num,
        ),
      );
      $components = array_merge($page_zero, $node->webform['components'], $page_preview);
      if (!$forward) {
        $components = array_reverse($components);
      }
      foreach ($components as $component) {
        if ($component['type'] == 'pagebreak') {
          if ($forward
               ? ($component['page_num'] > $form_state['storage']['page_num'])
               : ($component['page_num'] <= $form_state['storage']['page_num'])){
            $previous_pagebreak = $component;
          }
        }
        elseif (isset($previous_pagebreak)) {
          // If a component is shown on this page, advance to this page.
          $page_num = $previous_pagebreak['page_num'] + $forward - 1;
          if ($component['page_num'] == $page_num &&
              ($component['type'] == 'faux' || _webform_client_form_rule_check($node, $component, $page_num, $form_state['values']['submitted']) == WEBFORM_CONDITIONAL_INCLUDE)) {
            if ($component['type'] == 'faux') {
              if ($forward) {
                if (!$form_state['webform']['preview']) {
                  // Force a preview to avert an unintended submission via Next.
//                  $form_state['webform']['preview'] = TRUE;
//                  $form_state['storage']['preview'] = TRUE;
//                  $form_state['storage']['page_count']++;
                }
              }
              else {
                $page_num = max (1, $page_num);
              }
            }
            $form_state['storage']['page_num'] = $page_num;
            break; // LOOP EXIT
          }
        }
      }

    }

    // The form is done if the page number is greater than the page count.
    $form_state['webform_completed'] = $form_state['storage']['page_num'] > $form_state['storage']['page_count'];
  }

  // Merge any stored submission data for multistep forms.
  if (isset($form_state['storage']['submitted'])) {
    $original_values = is_array($form_state['values']['submitted']) ? $form_state['values']['submitted'] : array();
    unset($form_state['values']['submitted']);

    foreach ($form_state['storage']['submitted'] as $key => $val) {
      $form_state['values']['submitted'][$key] = $val;
    }
    foreach ($original_values as $key => $val) {
      $form_state['values']['submitted'][$key] = $val;
    }

    // Remove the variable so it doesn't show up in the additional processing.
    unset($original_values);
  }

  // Inform the submit handlers that a draft will be saved.
  $form_state['save_draft'] = in_array($form_state['values']['op'], array($draft_op, '__AUTOSAVE__')) ||
                              ($node->webform['auto_save'] && !$form_state['webform_completed'] && user_is_logged_in());

  // Determine what we need to do on the next page.
  if (!empty($form_state['save_draft']) || !$form_state['webform_completed']) {
    // Rebuild the form and display the current (on drafts) or next page.
    $form_state['rebuild'] = TRUE;
  }
  else {
    // Remove the form state storage now that we're done with the pages.
    $form_state['rebuild'] = FALSE;
    unset($form_state['storage']);
  }
}

At the moment we use a vanilla Drupal 7.32 with Webform 4.1. I installed webform_share a few minutes ago to export the webform if anybody needs ressources for testing.

Reopened (see last 2 comments)

@zuernBernhard -- When conditions hide the last page, the preview page should be shown to avoid an unintentional submit of the form. Are you saying that when the last page IS shown, you get a preview anyhow?

Closing as I believe my answer #22 resolves the issue.

Short of hacking the module, is there any way to disable this feature if skipping a page and submitting the form is the intended action?

Or ensure the last page isn't blank.