I’m actually using D9 to build a system with entities using sub-entities. The main entity system use the following path : /item/{item} Each sub entity is related to a main entity and use this path : /item/{item}/sub_item/{sub_item}

So to access the edit or delete form, the following pathes are required :

/item/{item}/sub_item/{sub_item}/edit /item/{item}/sub_item/{sub_item}/delete

For example : /item/1/sub_item/4/edit

I declared the following route :

entity.sub_item.edit_form:   path: '/item/{item}/sub_item/{sub_item}/edit'   defaults:     _entity_form: 'sub_item.edit'     _title: 'Edit sub item'   options:     _admin_route: TRUE     parameters:       item:         type: entity:item         with_config_overrides: TRUE       sub_item:         type: entity:sub_item         with_config_overrides: TRUE   requirements:     _permission: 'administer site configuration' 

Edit and Delete links are generated by list builder from getOperations. The list builder is on the following route : /item/1/sub_items (this is the "collection" to show the sub-items attached to main item).

I was hoping that the fact the current URL contained item/{item} can be directly re-used by the link generator, but it’s not the fact…

SymfonyComponentRoutingExceptionMissingMandatoryParametersException : Some mandatory parameters are missing ("item") to generate a URL for route "entity.sub_item.edit_form". in DrupalCoreRoutingUrlGenerator->doGenerate() (line 181 of /core/lib/Drupal/Core/Routing/UrlGenerator.php).

I tried to build a specific htmlRouteProvider class for my sub-item entity class but in this case too, the routes are built when cache are cleared, and I don’t have access to the item in the URL to set it…

So… My question is : I’m missing something to do it easily, or must I re-implement the "toUrl()" method of my sub-item entity class to include the new "item" parameter "on the fly" ?

Thanks in advance for any suggestion.

PS : it’s the solution I have actually in my sub-item entity class :

  public function toUrl($rel = 'canonical', array $options = []) {     $uri = parent::toUrl($rel, $options);     $uri->setRouteParameter('item', Drupal::routeMatch()->getRawParameter('item'));     return $uri;   } 

But maybe a better solution can be found ?