Create wp_theme_directory_constants() function and dynamic WordPress Themes folder

[mehrshaddarzi]

One of the needs of WordPress users is to dynamically modify the themes folder.

For Change themes folder name in (wp-content dir) you can added this code in wp-config.php :

define( 'WP_THEMES_DIR', "template" );

also for change complete path and url :

define( 'WP_THEMES_PATH', ABSPATH . "/public/template" );
define( 'WP_THEMES_URL', WP_SITEURL . "/public/template" );

This item works for WordPress Multi-site without problems.

[SergeyBiryukov]

Hi @mehrshaddarzi, welcome to WordPress Trac! Thanks for the ticket.

Have you considered using ​register_theme_directory() instead?

[mehrshaddarzi]

@SergeyBiryukov

There is a bug between register_theme_directory() and theme_root filter
For example, I wanted to changed the WordPress themes folder.

1. i renamed themes folder to templates.
2. i moved ~/home/wp-content/templates to ~/home/public/templates.
3. i created a mu-plugins with themes-dir.php and put the following code.

<?php
/**
 * Plugin Name: Change Themes folder
 * Description: A WordPress Plugin For Change themes folder
 * Author: Mehrshad Darzi
 * Version:     1.0.0
 */
register_theme_directory( ABSPATH . 'public/templates' );
add_filter( 'theme_root', function () { return ABSPATH . 'public/templates';  });
add_filter( 'theme_root_uri', function () { return home_url( '/public/templates' ); }, 10, 1 );

I got this error : ERROR: The theme directory "twentynineteen" does not exist..

then I reviewed the WordPress core code and found two wrong codes.
wp-includes/theme.php line 661 and 373.

if ( ! is_array( $wp_theme_directories ) || count( $wp_theme_directories ) <= 1 ) {
                return '/themes';
}

top code is wrong because theme_root filter not considered.

i changed code to :

if ( ( ! is_array( $wp_theme_directories ) || count( $wp_theme_directories ) <= 1 ) and ! has_filter( 'theme_root' ) ) {
                return '/themes';
}

And worked without problems.

i Created a new patch that Fixed all problem about WordPress themes according to register_theme_directory() function.
please check.

[mehrshaddarzi]

Fixed WordPress themes

[ocean90]

Related: #31620