From c4fe19b5d6fc226ad9dba8fe2f374efec21341f7 Mon Sep 17 00:00:00 2001
From: Kristiaan Van den Eynde <magentix@gmail.com>
Date: Fri, 17 Nov 2017 10:37:52 +0100
Subject: [PATCH] interdiff

---
 core/modules/field_ui/field_ui.module | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/core/modules/field_ui/field_ui.module b/core/modules/field_ui/field_ui.module
index 272353f..c90fa60 100644
--- a/core/modules/field_ui/field_ui.module
+++ b/core/modules/field_ui/field_ui.module
@@ -10,7 +10,7 @@
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Entity\EntityViewModeInterface;
 use Drupal\Core\Entity\EntityFormModeInterface;
-use Drupal\Core\Url;
+use Drupal\Core\Routing\RouteProviderLazyBuilder;
 use Drupal\field_ui\FieldUI;
 use Drupal\field_ui\Plugin\Derivative\FieldUiLocalTask;
 
@@ -109,6 +109,22 @@ function field_ui_entity_type_build(array &$entity_types) {
  * Implements hook_entity_type_alter().
  */
 function field_ui_entity_type_alter(array &$entity_types) {
+  // Because we are in the middle of building entity type definitions and we
+  // need information from another "build system" (routes), we need to build in
+  // an eternal loop prevention. Otherwise, if the route builder needs info
+  // about entity types, it will trigger yet another entity type build and we
+  // will keep looping back and forth between the two systems.
+  //
+  // Something like this is currently possible because Views' route subscriber.
+  // @see https://www.drupal.org/project/drupal/issues/2924075
+  //
+  // @todo Remove when the above issue has a fix.
+  $building = &drupal_static(__FUNCTION__, FALSE);
+  if ($building) {
+    return;
+  }
+  $building = TRUE;
+
   /** @var \Drupal\Core\Routing\RouteProvider $route_provider */
   $route_provider = \Drupal::service('router.route_provider');
 
@@ -117,12 +133,14 @@ function field_ui_entity_type_alter(array &$entity_types) {
     // Add manage fields and display link relations and templates if this entity
     // type is the bundle of another and that type has field UI enabled.
     if (($bundle_of = $entity_type->getBundleOf()) && ($base_route = $entity_types[$bundle_of]->get('field_ui_base_route'))) {
-      $field_ui_path = $route_provider->getRouteByName($base_route)->getPath() . '/fields';
-      $entity_type->setLinkTemplate('drupal:field-ui-fields', $field_ui_path);
+      $field_ui_path = $route_provider->getRouteByName($base_route)->getPath();
+      $entity_type->setLinkTemplate('drupal:field-ui-fields', $field_ui_path . '/fields');
       $entity_type->setLinkTemplate('drupal:field-ui-form-display', $field_ui_path . '/form-display');
       $entity_type->setLinkTemplate('drupal:field-ui-display', $field_ui_path . '/display');
     }
   }
+
+  $building = FALSE;
 }
 
 /**
-- 
2.8.1