Refactor LayoutBuilderLocalTaskDeriver to delegate local tasks to plugins

1. +++ b/core/modules/layout_builder/src/Plugin/Derivative/LayoutBuilderLocalTaskDeriver.php
   @@ -8,7 +8,9 @@
   +use Symfony\Component\Routing\RouteCollection;
   

   I think this is unused.

2. +++ b/core/modules/layout_builder/src/Plugin/Derivative/LayoutBuilderLocalTaskDeriver.php
   @@ -28,14 +30,26 @@ class LayoutBuilderLocalTaskDeriver extends DeriverBase implements ContainerDeri
   +  public function __construct(
   +    EntityTypeManagerInterface $entity_type_manager,
   +    SectionStorageManagerInterface $section_storage_manager) {
   

   Nit: Keep this on one line, please

3. +++ b/core/modules/layout_builder/src/Plugin/Derivative/LayoutBuilderLocalTaskDeriver.php
   @@ -51,84 +66,11 @@ public static function create(ContainerInterface $container, $base_plugin_id) {
   -  protected function getEntityTypesForDefaults() {
   ...
   -  protected function getEntityTypesForOverrides() {
   

   It's so great to remove this duplicate code!

Yay! Thanks.

This is a great refactor that will allow other implementations of LB to participate in the local tasks building.

Is this something that could be backported to 8.6, or is it sufficient of an internal API change that it's out of consideration?

I see no reason this couldn't be backported, but that's up to the committers.

+++ b/core/modules/layout_builder/src/SectionStorageInterface.php
@@ -78,6 +78,17 @@ public function getSectionListFromId($id);
+  public function buildLocalTasks($base_plugin_definition);

So I think this is an API change, as we don't have a base class so can't apply the 1:1 rule.

So I think we need a BC shim, which would be a new interface with this method and an instanceof check with a fall back.

Add an empty implementation to the base class, Drupal\layout_builder\Plugin\SectionStorage\SectionStorageBase.

Perfect

LGTM.

Thanks, can we get a change record here?

While trying to write the CR, I had a realization that while we absolutely need to provide Local Tasks in the current iteration of Layout Builder, we have no explicit need for them in the final designs. We're only using local tasks until #2936655: Layout Builder should use the toolbar modes system once it exists. is resolved.

So even though adding to the interface is supported by the BC policy, we don't want to.

CR is at https://www.drupal.org/node/2999418

This refactoring makes more sense IMO.

Adding review credit

Committed 58b776b and pushed to 8.7.x. Thanks!

Published change record

Backported to 8.6.x also.

Retroactively tagging