[field excerpt] when excerpt is empty

Hi,

If I was you, I made the excerpt field required, or use a (new) custom field to add a separate text block to your content.

To make the excerpt required, you can add this code to your functions.php (of your child theme):

add_filter('wp_insert_post_data', 'mandatory_excerpt');
function mandatory_excerpt($data) {
     
  /** Run excerpts only on certain post types */
  $screen = get_current_screen();
  if ((isset($data['post_type'])) && (isset($_REQUEST['action']))) {
      
      $post_type=$data['post_type'];
      $post_type_slug_excerpt_required= 'post';
      $post_action=$_REQUEST['action'];
       
      if (($post_type_slug_excerpt_required == $post_type) && ('editpost' == $post_action)) {
         
        //This filter is processing the correct post type proceed
        $excerpt = $data['post_excerpt'];
         
        if (empty($excerpt)) {
            //No excerpt!
            if ($data['post_status'] === 'publish') {
                add_filter('redirect_post_location', 'excerpt_error_message_redirect', '99');
            }
            //Change to draft
            $data['post_status'] = 'draft';     
        }       
      }     
  }
  return $data;
}
 
function excerpt_error_message_redirect($location) {
  remove_filter('redirect_post_location', 'excerpt_error_message_redirect', '99');
  return add_query_arg('excerpt_required', 1, $location);
}
function excerpt_admin_notice() {
  if (!isset($_GET['excerpt_required'])) return;
 
  switch (absint($_GET['excerpt_required'])) {
    case 1:
      $message = 'Excerpt is required to publish a post.';
      break;
    default:
      $message = 'Unexpected error';
  }
 
  echo '<div id="notice" class="error"><p>' . $message . '</p></div>';
}
add_action('admin_notices', 'excerpt_admin_notice');

Source

Peter