Why are the comments disabled by default on my custom_post_types?

Question

I am using a custom post type + taxonomies in a podcast solution for a client. The setting (settings >> discussion) for comments is set to "allow comments". When I add / edit posts under the "posts" tab, comments are enabled by default.

However, when I add / edit posts under the custom post type (podcast) - comments are disabled by default.

The user can still manually enable comments for each post, but this is obviously not ideal. Thoughts?

UPDATE: Relevant Code in functions.php

function create_my_post_types() {
    register_post_type( 'podcast',
        array(
            'labels' => array(
                'name' => __( 'Podcast' ),
                'singular_name' => __( 'Podcast' ),
                'new_item' => __( 'New Episode' ),
                'add_new_item' => __( 'Add New Episode' )
            ),
            'public' => true,
            'hierarchical' => true,
            'menu_icon' => get_stylesheet_directory_uri() . '/assets/podcast-icon.png', // 16px16
            'menu_position' => 9,
            'supports' => array( 'title', 'editor', 'comments', 'post-templates'),
            'register_meta_box_cb' => 'add_podcast_metaboxes' // This registers the metabox that we'll add later.
        )
    );
}

Answer 1

Ok - so I solved this. Here is what appears to be the problem.

Comments are disabled by default for custom-post-types. This happens even if you have them enabled in the overall settings

To fix it, all I had to do was the following:

1. In SETTINGS > DISCUSSION uncheck the "Allow people to post comments on new articles" setting.
2. Click "Save Changes"
3. Now go back and re-check "Allow people to post comments on new articles"
4. Click "Save Changes"

It seems that for custom post types you need to kind of kick-start this setting. All new posts for created custom-post-types will have the box enabled by default. Existing posts will retain their previous setting. I'm assuming it's the same for allowing trackbacks. Hopefully this helps someone...

Answer 2

This is the default state.. you need to change the "Supports line" where you build your custom post type..

Meaning this line:

// or something similer that starts the same

'supports' => array('title','editor','author','excerpt','revisions'),

To this line:

'supports' => array('title','editor','author','excerpt','comments','revisions'),

Hope this helps.
Cheers, Sagive.

ADDED FUNCTION (INSIDE FUNCTIONS FILE):

function default_comments_on( $data ) {
    if( $data['post_type'] == 'your_custom_post_name' ) {
        $data['comment_status'] = 1;
    }

    return $data;
}
add_filter( 'wp_insert_post_data', 'default_comments_on' );

Answer 3

None of the following suggestions worked for me. Sagive SEO's function almost worked for me. I checked my database to find that the only values for comment_status are open and closed. That function inserted 1 as a value. I revised the function and it seems to work perfect now. I hope this helps someone.

function default_comments_on( $data ) {
    if( $data['post_type'] == 'your_custom_post_type_name' ) {
        $data['comment_status'] = 'open';
    }

    return $data;
}
add_filter( 'wp_insert_post_data', 'default_comments_on' );

Answer 4

Just taking a random stab but do you have to add "comments" to the supports array parameter, in the register_post_type() call?