permastruct for custom post type not working in one of four cases

Question

I've created custom permalinks for various custom post types on a website. They all worked. Until recently I added another one, which I cannot get to work 8-o. The "company" struct is not working and gives a 404..

Can anyone spot a flaw in my thinking or put me on the right track? I must be forgetting something very stupid ;-)

Oh, I also went to the permalink settings page to flush the old permalinks / permalink cache / ...

Here's the code for the custom structure:

// rewrite rewrite
global $wp_rewrite;

$wp_rewrite->add_rewrite_tag("%merkname%", '([^/]+)', "merk=");
$wp_rewrite->add_permastruct('merk', '/merken/%merkname%', false);

$wp_rewrite->add_rewrite_tag("%modelname%", '([^/]+)', "model=");
$wp_rewrite->add_permastruct('model', '/merken/%merkname%/%modelname%', false);

$wp_rewrite->add_rewrite_tag("%carname%", '([^/]+)', "car=");
$wp_rewrite->add_permastruct('car', '/merken/%merkname%/%modelname%/%carname%', false);

$wp_rewrite->add_rewrite_tag("%companyname%", '([^/]+)', "company=");
$wp_rewrite->add_permastruct('company', '/company/%companyname%', false);

function kw_custom_permalink($permalink, $post, $leavename) {

    if ( '' != $permalink && !in_array($post->post_status, array('draft', 'pending', 'auto-draft')) ) {

        $merkname='';
        $modelname='';
        $carname='';
        $companyname='';

        if ( strpos($permalink, '%merkname%') !== false ) {
            $merkname = $post->post_name;
        }

        if ( strpos($permalink, '%modelname%') !== false ) {
            $merkpost = get_post( get_post_meta( $post->ID, "merk", true ) );
            $merkname = $merkpost->post_name;
            $modelname = $post->post_name;
        }

        if ( strpos($permalink, '%carname%') !== false ) {
            $merkpost = get_post( get_post_meta( $post->ID, "_car_merk", true ) );
            $merkname = $merkpost->post_name;

            $modelpost = get_post( get_post_meta( $post->ID, "_car_model", true ) );
            $modelname = $modelpost->post_name;

            $carname = $post->post_name;
        }

        if ( strpos($permalink, '%companyname%') !== false ) {
            $companyname = $post->post_name;
        }

        $permalink = str_replace(
            array(
                $leavename? '' : '%postname%',
                '%post_id%',
                '%merkname%',
                '%modelname%',
                '%carname%',
                '%companyname%',
                $leavename? '' : '%pagename%',
            ), 
            array(
                $post->post_name,
                $post->ID,
                $merkname,
                $modelname,
                $carname,
                $companyname,
                $post->post_name,
            ), 
            $permalink
            );

    }
    return $permalink;
}
add_filter('post_type_link', 'kw_custom_permalink', 10, 3);

Answer 1

You're currently placing your rewrite rules in the global scope, which means they execute as soon as your file is loaded, which may be too early. Instead try adding them on the init hook, or rewriting them to use the generate_rewrite_rules filter instead, e.g.:

add_action('generate_rewrite_rules', 'themes_dir_add_rewrites');

function themes_dir_add_rewrites() {
  $theme_name = next(explode('/themes/', get_stylesheet_directory()));

  global $wp_rewrite;
  $new_non_wp_rules = array(
    'css/(.*)'       => 'wp-content/themes/'. $theme_name . '/css/$1',
    'js/(.*)'        => 'wp-content/themes/'. $theme_name . '/js/$1',
    'images/wordpress-urls-rewrite/(.*)'    => 'wp-content/themes/'. $theme_name . '/images/wordpress-urls-rewrite/$1',
  );
  $wp_rewrite->non_wp_rules += $new_non_wp_rules;
}

Taken from Hongkiat

Or

function josfaber_add_rules() {
    global $wp_rewrite;

    $wp_rewrite->add_rewrite_tag("%merkname%", '([^/]+)', "merk=");
    $wp_rewrite->add_permastruct('merk', '/merken/%merkname%', false);

    $wp_rewrite->add_rewrite_tag("%modelname%", '([^/]+)', "model=");
    $wp_rewrite->add_permastruct('model', '/merken/%merkname%/%modelname%', false);

    $wp_rewrite->add_rewrite_tag("%carname%", '([^/]+)', "car=");
    $wp_rewrite->add_permastruct('car', '/merken/%merkname%/%modelname%/%carname%', false);

    $wp_rewrite->add_rewrite_tag("%companyname%", '([^/]+)', "company=");
    $wp_rewrite->add_permastruct('company', '/company/%companyname%', false);
}
add_action( 'init', 'josfaber_add_rules' );