"Link label to the referenced entity" changed behavior from Drupal 10.1 to 10.2

I think the change to default arguments to ::toUrl may have been the issue

It broke aggregator module too

The problem is with a change in functionality of calling a canonical view when the "Link label to the referenced entity" is switched on. In Drupal 10.1.x when an element does not have a canonical view Drupal "skips" requesting it, while in Drupal 10.2.x you get a WSOD when the canonical view/route is called.

For this I would propose not to show the "Link label to the referenced entity" for an element that does not have a canonical view. This would avoid Drupal calling something which does not exist. Example for this are the "From state"/"To state" fields from the contrib workflow module.

We could at least silently catch the exception in Views to avoid breaking things entirely.

Is there a core module that can be used to write a test for this?

This checkbox comes from \Drupal\Core\Field\Plugin\Field\FieldFormatter\EntityReferenceLabelFormatter, Views just reuses the field formatter, so not sure if this is something Views should be handling or the FieldFormatter itself.

@larowlan is 📌 Fall back to 'edit-form' as default $rel in EntityBase::toUrl() Fixed the change you are referring to? The formatter seems to catch the new exception thrown there so not sure.

Yeah that's the one that broke aggregator

Just run into this with search_api_saved_searches and the SavedSearchType entity. Changing to a bug report, because this broke a view that worked in 10.1 but not in 10.2.

The problem is that the entity declares the canonical and edit-form templates to be the same:

 *   links = {
 *     "canonical" = "/admin/config/search/search-api-saved-searches/type/{search_api_saved_search_type}/edit",
 *     "add-form" = "/admin/config/search/search-api-saved-searches/add-type",
 *     "edit-form" = "/admin/config/search/search-api-saved-searches/type/{search_api_saved_search_type}/edit",

then this code makes an assumption about the route name:

    if (isset($link_templates[$rel])) {
      $route_parameters = $this->urlRouteParameters($rel);
      $route_name = "entity.{$this->entityTypeId}." . str_replace(['-', 'drupal:'], ['_', ''], $rel);
      $uri = new Url($route_name, $route_parameters);
    }

However the entity.search_api_saved_search_type.canonical route does not actually exist - it shouldn't need to because the entity.search_api_saved_search_type.edit_form route does exist.

Perhaps the whole block in EntityBase::toUrl() needs reworking to ensure that the route that it selects does actually exist; if the canonical route doesn't exist it could fall back to the edit-form route instead?

Related too 🐛 Route "entity.workbench_email_template.canonical" does not exist Needs work