Entities with external urls as a uri relationship can not be deleted when menu_link_content is installed

+++ b/core/modules/menu_link_content/menu_link_content.module
@@ -103,6 +103,9 @@ function menu_link_content_entity_predelete(EntityInterface $entity) {
+    if (!$url->isRouted()) {
+      continue;
+    }

Let's add a comment here to explain the reason. We can RTBC it after that.

Test needs to fix $modules to protected https://www.drupal.org/node/2909426

Re-rolled the patch for 9.1.x-dev , and fixed $modules as protected.

Ignore the patch at #12. Re-rolled the patch for 9.1.x-dev , and fixed $modules as protected.

Thanks, for addressing the feedback. This looks ready to me.

+++ b/core/modules/menu_link_content/menu_link_content.module
@@ -104,6 +104,11 @@ function menu_link_content_entity_predelete(EntityInterface $entity) {
+    // Entities can provide uri relationships that are not routed, in
+    // this case getRouteParameters will throw an exception.

One nitpick, wrapped too early (do not exceed 80 chars)

Fixing #17, and stay RTBC.

+++ b/core/modules/menu_link_content/menu_link_content.module
@@ -104,8 +104,8 @@ function menu_link_content_entity_predelete(EntityInterface $entity) {
+    // getRouteParameters will throw an exception.
     if (!$url->isRouted()) {

Furthermore, getRouteParameters() would be better than getRouteParameters. Keep RTBC still.

+++ b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestExternal.php
@@ -0,0 +1,36 @@
+ *     "canonical" = "/entity_test_exteranl/{entity_test_exteranl}"

this should be external right? not exteranl

Updated patch #22 for 8.9.x as per the changes mentioned in #23, please review.

By mistake changed version, reverting back.

@larowlan, nice catch! Thanks

In general, patch gets committed to 9.1.x first. So uploading a patch against 9.1.x

Known random failure, re-queued.

Committed b2a49d3 and pushed to 9.1.x. Thanks!

C/p to 9.0.x

Queuing a test-run against 8.9.x

Doesn't apply to 8.9.x

As this is a bug and non-disruptive, backported to 8.9.x