Make site section vocabulary configurable and simplify settings form

Add a vocabulary selector to the settings form so the site section
vocabulary is no longer hardcoded. Remove node bundle checkboxes
(section_page/content_page are always included), keep user and group
as configurable parent targets. All hardcoded 'site_sections'
references in PHP replaced with dynamic config reads via helper.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Breadcrumb/SectionBreadcrumbBuilder.php

@@ -169,7 +169,7 @@ class SectionBreadcrumbBuilder implements BreadcrumbBuilderInterface {
         ];
       }
 
-      // If parent is taxonomy_term, that's our context (handled via site_sections).
+      // If parent is taxonomy_term, that's our context (handled via configured vocabulary).
       if ($parent_entity_type === 'taxonomy_term') {
         return [
           'type' => 'taxonomy_term',

src/Form/StructuralPagesSettingsForm.php

@@ -105,34 +105,39 @@ class StructuralPagesSettingsForm extends ConfigFormBase {
     foreach ($allowed_targets as $target) {
       $key = $target['entity_type'] . ':' . $target['bundle'];
       $enabled_targets[$key] = TRUE;
-      // Handle wildcard bundles.
-      if ($target['bundle'] === '*') {
-        $enabled_targets[$target['entity_type'] . ':*'] = TRUE;
-      }
     }
 
-    $form['description'] = [
-      '#type' => 'markup',
-      '#markup' => '<p>' . $this->t('Select which entity types and bundles can be used as parent for Content Page nodes. This allows creating hierarchical structures where content pages can be children of different entity types.') . '</p>',
-    ];
-
-    $form['context_info'] = [
-      '#type' => 'markup',
-      '#markup' => '<p>' . $this->t('<strong>Context behavior:</strong><br>
-        - <em>Node/Taxonomy</em>: Content pages inherit the site section from the parent.<br>
-        - <em>User</em>: Content pages are associated with the user profile page.<br>
-        - <em>Group</em>: Content pages are associated with the group.') . '</p>',
+    // Site section vocabulary selector.
+    $vocabularies = $this->entityTypeManager->getStorage('taxonomy_vocabulary')->loadMultiple();
+    $vocabulary_options = [];
+    foreach ($vocabularies as $vid => $vocabulary) {
+      $vocabulary_options[$vid] = $vocabulary->label();
+    }
+
+    $form['site_section_vocabulary'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Site section vocabulary'),
+      '#description' => $this->t('Select the taxonomy vocabulary used for site sections. Content pages and section pages will reference terms from this vocabulary.'),
+      '#options' => $vocabulary_options,
+      '#default_value' => $config->get('site_section_vocabulary') ?? 'site_sections',
+      '#required' => TRUE,
     ];
 
+    // Additional parent targets (user, group).
     $form['allowed_parent_targets'] = [
       '#type' => 'fieldset',
-      '#title' => $this->t('Allowed Parent Targets'),
+      '#title' => $this->t('Additional Parent Targets'),
       '#tree' => TRUE,
     ];
 
     $supportedEntityTypes = $this->handlerManager->getSupportedEntityTypes();
 
     foreach ($supportedEntityTypes as $entity_type => $label) {
+      // Skip taxonomy_term and node — managed automatically.
+      if ($entity_type === 'taxonomy_term' || $entity_type === 'node') {
+        continue;
+      }
+
       $form['allowed_parent_targets'][$entity_type] = [
         '#type' => 'details',
         '#title' => $label,
@@ -190,11 +195,23 @@ class StructuralPagesSettingsForm extends ConfigFormBase {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state): void {
-    $targets = [];
-    $values = $form_state->getValue('allowed_parent_targets');
+    $vocabulary = $form_state->getValue('site_section_vocabulary');
+    $values = $form_state->getValue('allowed_parent_targets') ?? [];
     $supportedEntityTypes = $this->handlerManager->getSupportedEntityTypes();
 
+    // Fixed targets: taxonomy vocabulary + module content types.
+    $targets = [
+      ['entity_type' => 'taxonomy_term', 'bundle' => $vocabulary],
+      ['entity_type' => 'node', 'bundle' => 'section_page'],
+      ['entity_type' => 'node', 'bundle' => 'content_page'],
+    ];
+
+    // Configurable targets: user, group, etc.
     foreach ($supportedEntityTypes as $entity_type => $label) {
+      if ($entity_type === 'taxonomy_term' || $entity_type === 'node') {
+        continue;
+      }
+
       if (empty($values[$entity_type])) {
         continue;
       }
@@ -209,7 +226,6 @@ class StructuralPagesSettingsForm extends ConfigFormBase {
       }
 
       foreach ($values[$entity_type] as $bundle => $enabled) {
-        // Skip the special "_all" key for groups if not enabled.
         if ($bundle === '_all') {
           continue;
         }
@@ -223,12 +239,16 @@ class StructuralPagesSettingsForm extends ConfigFormBase {
     }
 
     $this->config('structural_pages.settings')
+      ->set('site_section_vocabulary', $vocabulary)
       ->set('allowed_parent_targets', $targets)
       ->save();
 
     // Update field configuration to reflect new targets.
     $this->updateFieldConfiguration($targets);
 
+    // Update field_site_section target_bundles on both content types.
+    $this->updateSiteSectionFieldConfiguration($vocabulary);
+
     parent::submitForm($form, $form_state);
   }
 
@@ -297,4 +317,31 @@ class StructuralPagesSettingsForm extends ConfigFormBase {
     $this->messenger()->addStatus($this->t('Field configuration updated successfully.'));
   }
 
+  /**
+   * Updates field_site_section target_bundles on both content types.
+   *
+   * @param string $vocabulary
+   *   The vocabulary machine name to set as target bundle.
+   */
+  protected function updateSiteSectionFieldConfiguration(string $vocabulary): void {
+    $field_names = [
+      'node.section_page.field_site_section',
+      'node.content_page.field_site_section',
+    ];
+
+    $storage = $this->entityTypeManager->getStorage('field_config');
+
+    foreach ($field_names as $field_name) {
+      $field_config = $storage->load($field_name);
+      if (!$field_config) {
+        continue;
+      }
+
+      $settings = $field_config->getSettings();
+      $settings['handler_settings']['target_bundles'] = [$vocabulary => $vocabulary];
+      $field_config->setSettings($settings);
+      $field_config->save();
+    }
+  }
+
 }

src/Plugin/ParentEntityHandler/TaxonomyTermHandler.php

@@ -20,7 +20,7 @@ use Drupal\taxonomy\TermInterface;
   entity_type_id: 'taxonomy_term',
   clears_site_section: FALSE,
   sort_field: 'name',
-  bundle_restrictions: ['site_sections'],
+  bundle_restrictions: [],
   weight: 0,
 )]
 class TaxonomyTermHandler extends ParentEntityHandlerBase {
@@ -61,6 +61,19 @@ class TaxonomyTermHandler extends ParentEntityHandlerBase {
     }
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function handlesEntity(EntityInterface $entity): bool {
+    if ($entity->getEntityTypeId() !== 'taxonomy_term') {
+      return FALSE;
+    }
+
+    $vocabulary = \Drupal::config('structural_pages.settings')
+      ->get('site_section_vocabulary') ?? 'site_sections';
+    return $entity->bundle() === $vocabulary;
+  }
+
   /**
    * {@inheritdoc}
    */
@@ -69,8 +82,7 @@ class TaxonomyTermHandler extends ParentEntityHandlerBase {
       return NULL;
     }
 
-    // Only site_sections terms can be site sections.
-    if ($entity->bundle() !== 'site_sections') {
+    if (!$this->handlesEntity($entity)) {
       return NULL;
     }