get_post_types is not showing all registered posts

Question

When I call get_post_types() in a plugin the output is registering only the basic set of post types. Here is the output:

array(5) { ["post"]=> string(4) "post" ["page"]=> string(4) "page" ["attachment"]=> string(10) "attachment" ["revision"]=> string(8) "revision" ["nav_menu_item"]=> string(13) "nav_menu_item" }

In this wordpress theme, however, I have registered a custom post type called 'artist', but it is not showing up. If, however, I call get_post_types() in the index.php file it does how the registered posts:

array(8) { ["post"]=> string(4) "post" ["page"]=> string(4) "page" ["attachment"]=> string(10) "attachment" ["revision"]=> string(8) "revision" ["nav_menu_item"]=> string(13) "nav_menu_item" ["acf"]=> string(3) "acf" ["artist"]=> string(6) "artist" ["release"]=> string(7) "release" }

Does anyone know why this is happening and how to get around the problem?

Answer 1

You have to wait with your call until the theme has registered its post type (it really should not do that anyway):

add_action( 'after_setup_theme', 'list_post_types', 20 );

function list_post_types()
{
    var_export( get_post_types() );
}