Debugging node/route access

Question

I want to set a breakpoint in xdebug to debug an interesting issue the site is having regarding user access to certain nodes. My question is where do I do that in D8? Where, specifically, is the D8 replacement for user_access to be found?

Not using any form of node access, but am using Group and Content Moderation. The problem could lie with either of them, but I thought the best approach would be to break where Drupal decides whether a user has access to node/###/edit, then step from there.

The problem is that the user's role's permissions give all node and content moderation permissions for the applicable content type. Yet, when going to the admin/content page or admin/content/moderation, given two nodes of the same content type authored by a user of the given role, with the same node and moderation status, only one has an edit button. In viewing the nodes, only one has an edit link.

I have rebuilt permissions, to no effect.

Answer 1

The /node/{node}/edit path is defined by the entity.node.edit_form route. This route uses the _entity_access requirement to lookup access. When that route's requested the entity API will execute EntityAccessCheck::access() and NodeAccessControlHandler::access() to lookup the account permssions for the relevant node.

Answer 2

I found the best place to put debug code is in \Drupal\Core\Access\AccessManager::check. In my case...

    $result = AccessResult::neutral();
if (!empty($checks)) {
  $arguments_resolver = $this->argumentsResolverFactory->getArgumentsResolver($route_match, $account, $request);
  $result = AccessResult::allowed();
  foreach ($checks as $service_id) {
    $result = $result->andIf($this->performCheck($service_id, $arguments_resolver));
    // Begin debug
    if($route_match->getRouteName() == 'entity.node.edit_form') {
      $this_check = $this->performCheck($service_id, $arguments_resolver);
      dpm(compact('service_id', 'this_check'), __FILE__ . ":" . __LINE__);
    }
    // End debug
  }
}
// Begin debug
if($route_match->getRouteName() == 'entity.node.edit_form') {
  dpm($result, __FILE__ . ":" . __LINE__);
}
// End debug
return $return_as_object ? $result : $result->isAllowed();