Enable comments on PMPro Courses and Lessons.

pmpro-courses-add-comments.php

<?php
/**
 * Enable comments for Courses and Lessons for members with access.
 * People who don't have access will only be able to view comments only. Great for upselling lessons and courses.
 *
 * To add this code to your site, follow this guide - https://www.paidmembershipspro.com/documentation/templates/customizing-via-a-custom-plugin/
 */
function my_pmpro_courses_enable_comments( $open, $post_id ) {

	// Check if the person has access to the post type to comment.
	if ( function_exists( 'pmpro_has_membership_access' ) ) {
		if ( ! pmpro_has_membership_access( $post_id ) ) {
			return false;
		}
	}

	$courses_cpt = array( 'pmpro_course', 'pmpro_lesson' );
	$post = get_post( $post_id );

	if ( $post && in_array( $post->post_type, $courses_cpt ) ) {
		return true;
	}
	return $open;
}
add_filter( 'comments_open', 'my_pmpro_courses_enable_comments', 10, 2 );