List table $post is null in exports

[justinmaurerdotdev]

There are some (I believe, legitimate) cases where the Co-Authors column is failing to generate the correct values. One such example is the exports created in the Admin Columns plugin. I believe their plugin renders the list tables using WP_Query, but not actually doing a Loop. They, I suppose, rely on the manage_{$post->post_type}_posts_custom_column hook being used as advertised, where the post ID is taken from the callback's arguments. In the current Co-Authors code, the ID is taken from the global $post;, which, in these use cases, is not set.

The result is the "warning" below, which is accompanied by in an empty Co-Authors column in the export.

PHP Warning:  Attempt to read property "ID" on null in /var/www/html/wp-content/plugins/co-authors-plus/php/class-coauthors-plus.php on line 580
PHP Stack trace:
PHP   1. {main}() /var/www/html/wp-admin/edit.php:0
PHP   2. WP_Posts_List_Table->prepare_items() /var/www/html/wp-admin/edit.php:235
PHP   3. wp_edit_posts_query($q = *uninitialized*) /var/www/html/wp-admin/includes/class-wp-posts-list-table.php:165
PHP   4. wp($query_vars = ['post_type' => 'post', 'post_status' => '', 'perm' => '', 'order' => 'desc', 'orderby' => '15b2a971b5c28f', 'posts_per_page' => 200]) /var/www/html/wp-admin/includes/post.php:1306
PHP   5. WP->main($query_args = ['post_type' => 'post', 'post_status' => '', 'perm' => '', 'order' => 'desc', 'orderby' => '15b2a971b5c28f', 'posts_per_page' => 200]) /var/www/html/wp-includes/functions.php:1336
PHP   6. WP->query_posts() /var/www/html/wp-includes/class-wp.php:816
PHP   7. WP_Query->query($query = ['order' => 'desc', 'orderby' => '15b2a971b5c28f', 'author_name' => '[REDACTED]', 'post_type' => 'post', 'posts_per_page' => 200, 'post_status' => '', 'perm' => '']) /var/www/html/wp-includes/class-wp.php:696
PHP   8. WP_Query->get_posts() /var/www/html/wp-includes/class-wp-query.php:3852
PHP   9. apply_filters_ref_array($hook_name = 'the_posts', $args = [0 => [0 => class WP_Post { ... }, 1 => class WP_Post { ... }, 2 => class WP_Post { ... }, 3 => class WP_Post { ... },...