What is the difference between path and theme path in theme registry?

Question

I'm trying to alter the theme registry:

function comment_simplify_theme_registry_alter(&$theme_registry) {
  $module_path = drupal_get_path('module', 'comment_simplify') . '/tpl';
  $theme_registry['comment']['template'] = $module_path . '/comment';
  $theme_registry['comment']['theme path'] = $module_path;
  $theme_registry['comment_wrapper']['template'] = $module_path . '/comment-wrapper';
  $theme_registry['comment_wrapper']['theme path'] = $module_path;
}

Now this is what I have in theme registry:

comment_wrapper
  template: sites/all/modules/comment_simplify/tpl/comment-...
  path: themes/bartik/templates
  type: theme_engine
  theme path: sites/all/modules/comment_simplify/tpl
  render element: content

I want to know what the difference between path and theme path is.

Answer 1

From the hook_theme() docs:

• path: Override the path of the file to be used. Ordinarily the module or theme path will be used, but if the file will not be in the default path, include it here. This path should be relative to the Drupal root directory.
• theme path: (automatically derived) The directory path of the theme or module, so that it doesn't need to be looked up.