public custom posts not showing in my wordpress plugin

Question

I am building a WordPress plugin and I want to show all publicly registered custom post types (by theme or other plugins) in my plugin. But it only shows post and page custom post types not other publicly registered custom post types like book, movie, and so on.

My code:

class MyClass
{

    // Boot carbon fields plugin 
    public function lnpa_crb_load()
    {
        Carbon_Fields::boot();
    }

    // Register carbon fields and init submenu page 
    public function __construct()
    {
        add_action('carbon_fields_register_fields', array($this, 'lnpa_attach_theme_options'));
        add_action('after_setup_theme', array($this, 'lnpa_crb_load'));
        add_action('init', array($this, 'test_get_post_types'), 999);
    }

    public function test_get_post_types()
    {
        $post_types_arr =  array();

        $args = array(
            'public'   => true,
            // '_builtin' => true
        );

        // $post_types = get_post_types($args, 'names', 'and');
        // $post_types = array_diff($post_types, array('page', 'attachment'));
        $output = 'objects'; // Return post type objects
        $operator = 'and';

        $post_types = get_post_types($args, $output, $operator);

        foreach ($post_types as $post_type) {
            $post_types_arr[$post_type->name] = ucfirst($post_type->name);
        }

        return $post_types_arr;
    }

    // Declare carbon fields options
    public function lnpa_attach_theme_options()
    {
        Container::make('theme_options', __('AAA Settings', 'text_domain'))

            ->add_fields(array(

                Field::make('select', 'ggg_post_type', __('Select post type.'))
                    ->add_options($this->test_get_post_types())
            ));
    }
}

Answer 1

You are not seeing or that your function (test_get_post_types) is not returning the custom post types because if you look at the Carbon Fields source code, carbon_fields_register_fields is run by Carbon_Fields\Loader\trigger_fields_register() which is hooked on init with the priority 0. (See lines 113 and 44 in carbon-fields/core/Loader/Loader.php)

So that means, by the time your lnpa_attach_theme_options function runs (i.e. called via the carbon_fields_register_fields hook), those custom post types ("book", "movie", etc.) have not yet been registered because despite custom post types are commonly registered during init, the priority would not be 0 in normal cases.

Therefore, instead of passing the output of your test_get_post_types function, you should pass the function as a callable to the add_options() function, like so:

Field::make('select', 'ggg_post_type', __('Select post type.'))
    // Pass a callable, i.e. a function that is called later.
    ->add_options( array( $this, 'test_get_post_types' ) )

See the Carbon Fields documentation for more/other information.