Problem/Motivation
After upgrading to 8.8, our tests started throwing exceptions in various places that weren't checking if $route_match->getRouteObject() returned NULL. One of those places is in layout_builder_system_breadcrumb_alter
I'm not entirely sure what changed between 8.7 and 8.8, but it seems to be to do with rendering content controlled by layout_builder outside of a route context, for example during search indexing.
See the full stack trace below:
1) Drupal\Tests\apra_publications_search\Functional\PublicationsSearchTest::testPublicationsSearch
Error: Call to a member function hasOption() on null
/data/app/core/modules/layout_builder/layout_builder.module:336
/data/app/core/lib/Drupal/Core/Extension/ModuleHandler.php:539
/data/app/core/lib/Drupal/Core/Breadcrumb/BreadcrumbManager.php:94
/data/app/core/modules/system/src/Plugin/Block/SystemBreadcrumbBlock.php:72
/data/app/core/modules/layout_builder/src/EventSubscriber/BlockComponentRenderArray.php:104
/data/app/core/lib/Drupal/Component/EventDispatcher/ContainerAwareEventDispatcher.php:111
/data/app/core/modules/layout_builder/src/SectionComponent.php:90
/data/app/core/modules/layout_builder/src/Section.php:86
/data/app/core/modules/layout_builder/src/Entity/LayoutBuilderEntityViewDisplay.php:317
/data/app/core/modules/layout_builder/src/Entity/LayoutBuilderEntityViewDisplay.php:276
/data/app/core/lib/Drupal/Core/Entity/EntityViewBuilder.php:351
/data/app/core/modules/node/src/NodeViewBuilder.php:24
/data/app/core/lib/Drupal/Core/Entity/EntityViewBuilder.php:293
/data/app/core/lib/Drupal/Core/Entity/EntityViewBuilder.php:250
/data/app/core/lib/Drupal/Core/Security/DoTrustedCallbackTrait.php:100
/data/app/core/lib/Drupal/Core/Render/Renderer.php:781
/data/app/core/lib/Drupal/Core/Render/Renderer.php:372
/data/app/core/lib/Drupal/Core/Render/Renderer.php:200
/data/app/core/lib/Drupal/Core/Render/Renderer.php:156
/data/app/core/lib/Drupal/Core/Render/Renderer.php:573
/data/app/core/lib/Drupal/Core/Render/Renderer.php:157
/data/app/modules/contrib/search_api/src/Plugin/search_api/processor/RenderedItem.php:276
/data/app/modules/contrib/search_api/src/Item/Item.php:272
/data/app/modules/contrib/search_api/src/Entity/Index.php:975
/data/app/modules/contrib/search_api/src/Utility/PostRequestIndexing.php:84
/data/app/modules/custom/apra_tests/tests/src/Functional/ApraTestBase.php:90
/data/app/modules/custom/apra_publications_search/tests/src/Functional/PublicationsSearchTest.php:33
Proposed resolution
Check $route_match->getRouteObject() is not NULL.