Why does querying on post_tags (which has been applied to custom post types) only return posts?

Question

So I've created a little jquery cycle based feature rotator that pulls from the post_tags. I added the post tags to my other custom post types like this:

register_taxonomy_for_object_type('post_tag', 'reviews');
register_taxonomy_for_object_type('post_tag', 'interviews');
//...

When I add a 'featured' tag to one of my reviews and one of my interviews, and query for it thusly:

$query = new WP_Query( array( 'post_tag' => 'featured' ) );

I get two random posts instead of the two expected results. Any ideas?

Answer 1

Take a careful look at the arguments for WP_Query. By default, it queries for the post type post.

To select your custom post types, you need to change your query a little:

$query = new WP_Query( array(
    'post_type' => array( 'reviews', 'interviews' ),
    'post_tag'  => 'featured' 
) );