I am trying to include a rating comment meta value in the subject line of the email that notifies authors that someone has left a new comment (and, in my case, a rating) on their post.

function mycustomfilter_comment_notification_subject( $subject, $comment_id ) {
        $comment = get_comment( $comment_id );

        $subject = get_the_title( $comment->comment_post_ID ) . ': ' . get_comment_meta( $comment->comment_ID, 'rating', true ) . ' star rating';

        return $subject;
add_filter( 'comment_notification_subject', 'mycustomfilter_comment_notification_subject', 10, 2 );

The get_comment_meta() call is failing. It also fails when I try and output the same comment meta data using the comment_notification_text filter.

The rating value is being saved to the database as I can access this variable in a custom wp_list_comments() callback I have prepared.

Any idea why my email code is failing? Many thanks.

  • Not sure about an actual answer, but I do note that $comment->comment_ID in get_comment_meta( $comment->comment_ID, 'rating', true ) is unnecessary as you already have the $comment_id variable from the filter so you should use that there instead: get_comment_meta( $comment_id, 'rating', true ). Same in get_the_title() I guess. Might help.
    – Peter HvD
    Aug 21, 2018 at 13:39
  • Thanks Peter. What actually finally fixed the problem was simply adding a priority number of 5 to the comment_post action that was saving my rating value. Aug 22, 2018 at 9:41

1 Answer 1


The solution was to add a priority number to the comment_post action that was saving my rating value, as shown below:

function save_comment_meta_data( $comment_id ) {
    if ( ( isset( $_POST['rating'] ) ) && ( $_POST['rating'] != '') ) {
        $rating = wp_filter_nohtml_kses($_POST['rating']);

        add_comment_meta( $comment_id, 'rating', $rating );
add_action( 'comment_post', 'save_comment_meta_data', 5 ); // Adding a priority number of 5 fixed the problem!

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