Notify Post Author of Comments

<?php
add_filter( 'comment_notification_recipients', 'scseed_always_notify_post_author', 10, 2 );
if ( ! function_exists( 'scseed_always_notify_post_author' ) ) {
    function scseed_always_notify_post_author( $emails, $comment_id ) {
        $comment = get_comment( $comment_id );
        if ( ! $comment ) {
            return $emails;
        }
        $post   = get_post( $comment->comment_post_ID );
        $author = get_userdata( $post->post_author );
        if ( ! $author || empty( $author->user_email ) ) {
            return $emails;
        }
        // Skip notification if the commenter is the post author.
        if ( $comment->comment_author_email === $author->user_email ) {
            return $emails;
        }
        if ( ! in_array( $author->user_email, $emails, true ) ) {
            $emails[] = $author->user_email;
        }
        return $emails;
    }
}