From e13e5590edf6be489da5b06c2500e9b07e7a5ee7 Mon Sep 17 00:00:00 2001
From: Lee Rowlands <lee.rowlands@previousnext.com.au>
Date: Thu, 9 Sep 2021 10:00:01 +1000
Subject: [PATCH] Issue #3104980 by danflanagan8, acbramley:
 layout_builder_system_breadcrumb_alter doesn't check for a null route object

(cherry picked from commit ef493a71d5e4a74e8809a3a778985df08d48d4bf)
---
 .../layout_builder/layout_builder.module      |  2 +-
 .../LayoutBuilderBreadcrumbAlterTest.php      | 33 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 core/modules/layout_builder/tests/src/Kernel/LayoutBuilderBreadcrumbAlterTest.php

diff --git a/core/modules/layout_builder/layout_builder.module b/core/modules/layout_builder/layout_builder.module
index 4631de2547c..4553f0cada2 100644
--- a/core/modules/layout_builder/layout_builder.module
+++ b/core/modules/layout_builder/layout_builder.module
@@ -334,7 +334,7 @@ function layout_builder_plugin_filter_layout_alter(array &$definitions, array $e
  */
 function layout_builder_system_breadcrumb_alter(Breadcrumb &$breadcrumb, RouteMatchInterface $route_match, array $context) {
   // Remove the extra 'Manage display' breadcrumb for Layout Builder defaults.
-  if ($route_match->getRouteObject()->hasOption('_layout_builder') && $route_match->getParameter('section_storage_type') === 'defaults') {
+  if ($route_match->getRouteObject() && $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()) {
diff --git a/core/modules/layout_builder/tests/src/Kernel/LayoutBuilderBreadcrumbAlterTest.php b/core/modules/layout_builder/tests/src/Kernel/LayoutBuilderBreadcrumbAlterTest.php
new file mode 100644
index 00000000000..113adc2576d
--- /dev/null
+++ b/core/modules/layout_builder/tests/src/Kernel/LayoutBuilderBreadcrumbAlterTest.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Drupal\Tests\layout_builder\Kernel;
+
+use Drupal\Core\Breadcrumb\Breadcrumb;
+use Drupal\Core\Routing\NullRouteMatch;
+use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;
+
+/**
+ * Tests layout_builder_system_breadcrumb_alter().
+ *
+ * @group layout_builder
+ */
+class LayoutBuilderBreadcrumbAlterTest extends EntityKernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'layout_builder',
+    'layout_discovery',
+  ];
+
+  /**
+   * Check that there are no errors when alter called with null route match.
+   */
+  public function testBreadcrumbAlterNullRouteMatch() {
+    $breadcrumb = new Breadcrumb();
+    $route_match = new NullRouteMatch();
+    layout_builder_system_breadcrumb_alter($breadcrumb, $route_match, []);
+  }
+
+}