WordPress: Set specific menus (theme locations) to auto-add pages

wp-cli-auto-add-pages-to-menu.php

<?php
/**
 *  Allows programatically seting of specific menu locations (or more specifically, 
 *  the menus assigned to those locations) to automatically add new pages.
 *  [I.e. enables the 'Automatically add new top-level pages to this menu' setting]
 *  
 *  Usage (via WP CLI):
 *  - Add file to mu-plugins folder (might also work in functions.php?)
 *  - Get theme menu location slugs you want to enable auto-added pages (e.g. 'home' and 'footer-nav')
 *  - From the command line (SSH or otherwise), call:
 *  
 *  wp set-auto-add-menus home footer-nav
 *
 *  For multisite usage:
 *  
 *  wp site list --field=url | xargs -n1 -I % wp --url=% set-auto-add-menus home footer-nav
 *
*/
if ( ! class_exists( 'WP_CLI' ) ) {
  return;
}

$set_auto_add_menus = function( $args, $assoc_args ) {
  $theme_locations = get_nav_menu_locations();
  $menus_to_auto_add = array();
  $nav_menu_options = get_option( 'nav_menu_options', array() );
  if ( ! isset( $nav_menu_options['auto_add'] ) ) {
    $nav_menu_options['auto_add'] = array();
  }

  foreach( $args as $menu_name ) {
    if ( isset( $theme_locations[$menu_name] ) && $theme_locations[$menu_name] ) {
      $menus_to_auto_add[] = $theme_locations[$menu_name];
    }
  }

  foreach( $menus_to_auto_add as $menu_id ) {
    if ( ! in_array( $menu_id, $nav_menu_options['auto_add'] ) ) {
      $nav_menu_options['auto_add'][] = $menu_id;
    }
  }

  $update = update_option( 'nav_menu_options', $nav_menu_options );

  // Useful for multisite application.
  if ( $update ) {
    WP_CLI::success( home_url('/') );
  } else {
    WP_CLI::warning( home_url('/') );
  }

};

WP_CLI::add_command( 'set-auto-add-menus', $set_auto_add_menus );