Issue #3090941 by raman.b, breakfull, jmdeleon, amd.miri, tim.plunkett,...

Issue #3090941 by raman.b, breakfull, jmdeleon, amd.miri, tim.plunkett, rwohleb: Layout builder assumes all breadcrumb links are routable

core/modules/layout_builder/layout_builder.module

@@ -336,6 +336,9 @@ function layout_builder_system_breadcrumb_alter(Breadcrumb &$breadcrumb, RouteMa
   if ($route_match->getRouteObject()->hasOption('_layout_builder') && $route_match->getParameter('section_storage_type') === 'defaults') {
     $links = array_filter($breadcrumb->getLinks(), function (Link $link) use ($route_match) {
       $entity_type_id = $route_match->getParameter('entity_type_id');
+      if (!$link->getUrl()->isRouted()) {
+        return TRUE;
+      }
       return $link->getUrl()->getRouteName() !== "entity.entity_view_display.$entity_type_id.default";
     });
     // Links cannot be removed from an existing breadcrumb object. Create a new

core/modules/layout_builder/tests/modules/layout_builder_test/layout_builder_test.module

@@ -5,10 +5,14 @@
  * Provides hook implementations for Layout Builder tests.
  */
 
+use Drupal\Core\Breadcrumb\Breadcrumb;
 use Drupal\Core\Entity\Display\EntityFormDisplayInterface;
 use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Link;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\Core\Url;
 
 /**
  * Implements hook_plugin_filter_TYPE__CONSUMER_alter().
@@ -106,3 +110,24 @@ function layout_builder_entity_form_display_alter(EntityFormDisplayInterface $fo
     ]);
   }
 }
+
+/**
+ * Implements hook_system_breadcrumb_alter().
+ */
+function layout_builder_test_system_breadcrumb_alter(Breadcrumb &$breadcrumb, RouteMatchInterface $route_match, array $context) {
+  $breadcrumb->addLink(Link::fromTextAndUrl('External link', Url::fromUri('http://www.example.com')));
+}
+
+/**
+ * Implements hook_module_implements_alter().
+ */
+function layout_builder_test_module_implements_alter(&$implementations, $hook) {
+  if ($hook === 'system_breadcrumb_alter') {
+    // Move our hook_system_breadcrumb_alter() implementation to run before
+    // layout_builder_system_breadcrumb_alter().
+    $group = $implementations['layout_builder_test'];
+    $implementations = [
+      'layout_builder_test' => $group,
+    ] + $implementations;
+  }
+}

core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php

@@ -1230,6 +1230,7 @@ public function testBreadcrumb() {
       'Content types' => $base_path . 'admin/structure/types',
       'Bundle with section field' => $base_path . 'admin/structure/types/manage/bundle_with_section_field',
       'Manage display' => $base_path . 'admin/structure/types/manage/bundle_with_section_field/display/default',
+      'External link' => 'http://www.example.com',
     ];
     $this->assertSame($expected, $breadcrumb_titles);
   }