Notice in redirect_guess_404_permalink() when post type is an array

[junaidbhura]

When manipulating URLs, it sometimes becomes necessary to update the query using the pre_get_posts hook.

If we set the post type to an array in the pre_get_posts hook like so:

$query->set( 'post_type', array( 'post', 'page', 'my_cpt' ) );

On a 404 page, we get a notice when WP_DEBUG is set to true:

Notice: wpdb::prepare was called incorrectly. The query only expected one placeholder, but an array of multiple placeholders was sent.

This is caused by the following code in redirect_guess_404_permalink():

$where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));

This can be fixed by looking for an array and updating the query.