WP 6.4 Theme Path Fixer

plugin.php

<?php
/*
 * Plugin Name:       WP 6.4 Theme path fixer
 * Plugin URI:        https://gist.github.com/joemcgill/dd569c287013ad545f41495f93d7a27e
 * Description:       Fix problems with theme directory memoization in WP 6.4.
 * Version:           1.0
 * Requires at least: 6.4
 * Author:            Joe McGill
 * Author URI:        https://joemcgill.net
 * License:           GPL v2 or later
 * License URI:       https://www.gnu.org/licenses/gpl-2.0.html
 */
 
// Reset template and stylesheet paths prior to theme setup.
add_action( 'setup_theme', function () {
	$GLOBALS['wp_template_path']   = null;
	$GLOBALS['wp_stylesheet_path'] = null;
} );

// Add a noop filter to bypass future memoization.
add_filter( 'stylesheet_directory', function ( $dir ) {
	return $dir;
} );

// Add a noop filter to bypass future memoization.
add_filter( 'template_directory', function ( $dir ) {
	return $dir;
} );