Registry::completeSuggestion

protected Registry::completeSuggestion($hook, array &$cache)

protected function completeSuggestion($hook, array &$cache) {
  $previous_hook = $hook;
  $incomplete_previous_hook = array();
  while ((!isset($cache[$previous_hook]) || isset($cache[$previous_hook]['incomplete preprocess functions']))
   && $pos = strrpos($previous_hook, '__')) {
    if (isset($cache[$previous_hook]) && !$incomplete_previous_hook && isset($cache[$previous_hook]['incomplete preprocess functions'])) {
      $incomplete_previous_hook = $cache[$previous_hook];
      unset($incomplete_previous_hook['incomplete preprocess functions']);
    }
    $previous_hook = substr($previous_hook, 0, $pos);

    // If base hook exists clone of it for the preprocess function
    // without a template.
    // @see https://www.drupal.org/node/2457295
    if (isset($cache[$previous_hook]) && !isset($cache[$previous_hook]['incomplete preprocess functions'])) {
      $cache[$hook] = $incomplete_previous_hook + $cache[$previous_hook];
      if (isset($incomplete_previous_hook['preprocess functions'])) {
        $diff = array_diff($incomplete_previous_hook['preprocess functions'], $cache[$previous_hook]['preprocess functions']);
        $cache[$hook]['preprocess functions'] = array_merge($cache[$previous_hook]['preprocess functions'], $diff);
      }
      // If a base hook isn't set, this is the actual base hook.
      if (!isset($cache[$previous_hook]['base hook'])) {
        $cache[$hook]['base hook'] = $previous_hook;
      }
    }
  }
}