Screwing around with 'An illegal choice has been detected. Please contact the site administrator.' error messages in Drupal

gistfile1.aw

<?php

/**
 * Validation handler for blah_node_form
 */
function wpf_ui_blah_node_form_validate(&$form, &$form_state) {
  $errors = form_set_error();
  
  // This ensures that empty select responses are dealt with correctly
  $error_text = 'An illegal choice has been detected. Please contact the site administrator.';
  $empty_val = 'EMPTY';
  $count = 0;
  foreach ($errors as $key => $error) {
    if ($error == $error_text) {
      $keys = explode('][', $key);
      $formpart = $form;
      $values = $form_state['values'];
      foreach ($keys as $i) {
        $formpart = $formpart[$i];
        $values = $values[$i];
      }
      if ($formpart['#type'] == 'select') {
        if (is_array($values) && isset($values[0]['tid'])) {
          $values = $values[0]['tid'];
        }
        if ($values == $empty_val) {
          $errors[$key] = t('%field field is required.', array('%field' => $formpart['#title']));
          $count++;
        }
      }
    }
  }
  
  // Removing the unnecessary messages
  foreach ($_SESSION['messages']['error'] as $key => $message) {
    if ($message == $error_text && $count > 0) {
      unset($_SESSION['messages']['error'][$key]);
      $count--;
    }
  }
  
  // Resetting and re-adding necessary error messages
  drupal_static('form_set_error', array(), TRUE);
  foreach ($errors as $key => $error) {
    form_set_error($key, $error);
  }
}

?>