是，将删除整个旧目录。因此，将文件存储在上载目录中，并将其他数据存储在数据库中，以保留所有更改。

来自类Plugin_Upgrader:

//Hooked to upgrade_clear_destination
function delete_old_plugin($removed, $local_destination, $remote_destination, $plugin) {
    global $wp_filesystem;

    if ( is_wp_error($removed) )
        return $removed; //Pass errors through.

    $plugin = isset($plugin[\'plugin\']) ? $plugin[\'plugin\'] : \'\';
    if ( empty($plugin) )
        return new WP_Error(\'bad_request\', $this->strings[\'bad_request\']);

    $plugins_dir = $wp_filesystem->wp_plugins_dir();
    $this_plugin_dir = trailingslashit( dirname($plugins_dir . $plugin) );

    if ( ! $wp_filesystem->exists($this_plugin_dir) ) //If its already vanished.
        return $removed;

    // If plugin is in its own directory, recursively delete the directory.
    if ( strpos($plugin, \'/\') && $this_plugin_dir != $plugins_dir ) //base check on if plugin includes directory separator AND that its not the root plugin folder
        $deleted = $wp_filesystem->delete($this_plugin_dir, true);
    else
        $deleted = $wp_filesystem->delete($plugins_dir . $plugin);

    if ( ! $deleted )
        return new WP_Error(\'remove_old_failed\', $this->strings[\'remove_old_failed\']);

    return true;