Fix #167 (ManyToMany cache purge), #113 edge cases, and PageDataProvider 500 on unknown path

- PropagateUpdatesListener: walk getScheduledCollectionUpdates/Deletions to purge
  owning entities (Page/Layout) when ComponentGroup ManyToMany joins change
- PageDataProvider.getPageData: catch exceptions from getResourceFromIri so invalid
  paths (e.g. /unknown-path) return null instead of 500
- Behat: two new component_groups.feature scenarios verify Page/Layout cache purge
  after PATCH links an existing ComponentGroup
- Behat: two new dynamic_page.feature scenarios confirm admin fetch without path
  header and fetch with unknown path both return 200 with component=null
- Behat: security.feature scenario confirms /me resolves by username after user
  entity is recreated with a new database ID (no code change needed)

Author: silverbackdan

features/bootstrap/DoctrineContext.php

@@ -201,6 +201,24 @@ public function deleteLoggedInUser(): void
         $this->manager->clear();
     }
 
+    /**
+     * @Given the logged in user has been recreated with the same username
+     */
+    public function theLoggedInUserHasBeenRecreatedWithSameUsername(): void
+    {
+        $user = new User();
+        $user
+            ->setRoles(['ROLE_ADMIN'])
+            ->setUsername('new_user')
+            ->setEmailAddress('recreated@example.com')
+            ->setPassword($this->passwordHasher->hashPassword($user, 'password'))
+            ->setEnabled(true)
+            ->setEmailAddressVerified(true);
+        $this->timestampedHelper->persistTimestampedFields($user, true);
+        $this->manager->persist($user);
+        $this->manager->flush();
+    }
+
     /**
      * @Given there is a :type form
      */

features/main/component_groups.feature

@@ -105,3 +105,23 @@ Feature: ComponentGroup resource
     Then the response status code should be 200
     And the JSON node "componentPositions" should have 1 element
     And the JSON node "componentPositions[0]" should be equal to the IRI of the resource "position_0"
+
+  @loginAdmin
+  Scenario: Linking an existing ComponentGroup to a Page via PATCH purges the Page from the cache
+    Given there is a Page
+    And there is a ComponentGroup with 0 components
+    When I send a "PATCH" request to the resource "component_group" with data:
+      | pages                             |
+      | json_decode([ "resource[page]" ]) |
+    Then the response status code should be 200
+    And the resource "page" should be purged from the cache
+
+  @loginAdmin
+  Scenario: Linking an existing ComponentGroup to a Layout via PATCH purges the Layout from the cache
+    Given there is a Layout
+    And there is a ComponentGroup with 0 components
+    When I send a "PATCH" request to the resource "component_group" with data:
+      | layouts                               |
+      | json_decode([ "resource[layout]" ]) |
+    Then the response status code should be 200
+    And the resource "layout" should be purged from the cache

features/main/dynamic_page.feature

@@ -65,3 +65,20 @@ Feature: Dynamic pages
     Then the response status code should be 200
     And the resource "component_position" should exist
     And the resource "component_position" should be purged from the cache
+
+  @loginAdmin
+  Scenario: An admin can fetch a pageDataProperty position without a path header and the component slot is not resolved
+    Given there is a PageData resource with the route path "/page-data"
+    When I send a "GET" request to the resource "component_position"
+    Then the response status code should be 200
+    And the JSON node "pageDataProperty" should be equal to "component"
+    And the JSON node "component" should be null
+
+  @loginAdmin
+  Scenario: Fetching a pageDataProperty position with a path that has no matching page data returns the position without a component
+    Given there is a PageData resource with the route path "/page-data"
+    And I add "path" header equal to "/unknown-path"
+    When I send a "GET" request to the resource "component_position"
+    Then the response status code should be 200
+    And the JSON node "pageDataProperty" should be equal to "component"
+    And the JSON node "component" should be null

features/main/security.feature

@@ -185,3 +185,11 @@ Feature: Restrict loading of components and routes
     When I send a "GET" request to "/me"
     Then the response status code should be 401
     And the response should have a "api_components" cookie with max age less than 2
+
+  @loginAdmin
+  Scenario: GET /me resolves the user by username even after the user entity is recreated with a new database ID
+    Given the logged in user has been deleted from the database
+    And the logged in user has been recreated with the same username
+    When I send a "GET" request to "/me"
+    Then the response status code should be 200
+    And the JSON node "username" should be equal to "new_user"

src/DataProvider/PageDataProvider.php

@@ -65,7 +65,11 @@ public function getPageData(): ?AbstractPageData
 
         $route = $this->routeRepository->findOneByIdOrPath($path);
         if (!$route) {
-            $object = $this->iriConverter->getResourceFromIri($path);
+            try {
+                $object = $this->iriConverter->getResourceFromIri($path);
+            } catch (\Exception) {
+                return null;
+            }
             if ($object instanceof AbstractPageData) {
                 return $object;
             }

src/EventListener/Doctrine/PropagateUpdatesListener.php

@@ -75,6 +75,18 @@ public function onFlush(OnFlushEventArgs $eventArgs): void
             $this->gatherResourceAndAssociated($entity, 'deleted', $em, $uow);
         }
 
+        // ManyToMany join table changes — purge the owning entity's cache
+        foreach ($uow->getScheduledCollectionUpdates() as $collection) {
+            if ($owner = $collection->getOwner()) {
+                $this->collectUpdatedResource($owner, 'updated');
+            }
+        }
+        foreach ($uow->getScheduledCollectionDeletions() as $collection) {
+            if ($owner = $collection->getOwner()) {
+                $this->collectUpdatedResource($owner, 'updated');
+            }
+        }
+
         $this->collectUpdatedPageDataAndPositions();
     }