WordPress Version: 5.4
/**
* Determines if the specified post is a revision.
*
* @since 2.6.0
*
* @param int|WP_Post $post Post ID or post object.
* @return int|false ID of revision's parent on success, false if not a revision.
*/
function wp_is_post_revision($post)
{
$post = wp_get_post_revision($post);
if (!$post) {
return false;
}
return (int) $post->post_parent;
}