User A authored and published a post. In that post, User A selected User B as the "Manager" (a custom meta field).
How can I allow User B to edit any post in which they are selected as the "Manager"?
I'm comfortable with code. Looking for a way to programmatically hook into the check for who can edit a post.
Looking at current_user_can()'s documentation, I see that it uses WP_User::has_cap(). So if your code (or the WP core code) uses something like current_user_can( 'edit_post', $post->ID ) to determine if the current user can edit the current post, you can use the user_has_cap filter (called in WP_User::has_cap()):
add_filter( 'user_has_cap', 'wpse360937_allow_manager', 10, 4 ); function wpse360937_allow_manager( $allcaps, $caps, $args, $user ) { // Bail out if we're not asking about a post: if ( 'edit_post' != $args[0] ) { return $allcaps; } // Bail out for users who can already edit others posts: if ( $allcaps['edit_others_posts'] ) { return $allcaps; } // Bail out if the user is the post author: if ( $args[1] == $post->post_author ) { return $allcaps; } $post_id = $args[2]; $manager_id = get_post_meta( $post_id, 'manager', true ); // Assumes the meta field is called "manager" // and contains the User ID of the manager. if ( $manager_id == $user->ID ) { $allcaps[ $caps[0] ] = true; } return $allcaps; } (Code partly based on the User Contributed Notes on the user_has_cap filter docs.)
