Issue #2862982 by jsbalsera, borisson_: Selecting the wrong widget in a Facet...

Issue #2862982 by jsbalsera, borisson_: Selecting the wrong widget in a Facet for a Rest export causes an exception and a white page

modules/rest_facets/tests/src/Functional/RestIntegrationTest.php

@@ -213,4 +213,26 @@ class RestIntegrationTest extends FacetsTestBase {
 
   }
 
+  /**
+   * Tests that the system raises an error when selecting the wrong widget.
+   */
+  public function testWidgetSelection() {
+    $name = 'Type';
+    $id = 'type';
+
+    // Add a new facet to filter by content type.
+    $this->createFacet($name, $id, 'type', 'rest_export_1', 'views_rest__search_api_rest_test_view');
+
+    // Use the array widget.
+    $facet_edit_page = '/admin/config/search/facets/' . $id . '/edit';
+    $this->drupalGet($facet_edit_page);
+    $this->assertResponse(200);
+
+    $this->drupalPostForm(NULL, ['widget' => 'checkbox'], $this->t('Configure widget'));
+    $this->assertText('The Facet source is a Rest export. Please select a raw widget.');
+
+    $this->drupalPostForm(NULL, ['widget' => 'array'], $this->t('Configure widget'));
+    $this->assertNoText('The Facet source is a Rest export. Please select a raw widget.');
+  }
+
 }

src/FacetSource/SearchApiFacetSourceInterface.php

@@ -5,7 +5,7 @@ namespace Drupal\facets\FacetSource;
 /**
  * A facet source that uses Search API as a base.
  */
-interface SearchApiFacetSourceInterface {
+interface SearchApiFacetSourceInterface extends FacetSourcePluginInterface {
 
   /**
    * Returns the search_api index.
@@ -15,4 +15,12 @@ interface SearchApiFacetSourceInterface {
    */
   public function getIndex();
 
+
+  /**
+   * Retrieves the Search API display plugin associated with this facet source.
+   *
+   * @return \Drupal\search_api\Display\DisplayInterface
+   *   The Search API display plugin associated with this facet source.
+   */
+  public function getDisplay();
 }

src/Form/FacetForm.php

@@ -575,6 +575,15 @@ class FacetForm extends EntityForm {
       }
     }
 
+    // Only widgets that return an array can work with rest facet sources, so if
+    // the user has selected another widget, we should point them to their
+    // misconfiguration.
+    if ($facet->getFacetSource()->getDisplay() instanceof \Drupal\search_api\Plugin\search_api\display\ViewsRestDisplay) {
+      if (strpos($values['widget'], 'array') === FALSE) {
+        $form_state->setErrorByName('widget', $this->t('The Facet source is a Rest export. Please select a raw widget.'));
+      }
+    }
+
     // Validate url alias.
     $url_alias = $form_state->getValue(['facet_settings', 'url_alias']);
     if ($url_alias == 'page') {

src/Plugin/facets/facet_source/SearchApiDisplay.php

@@ -8,6 +8,7 @@ use Drupal\Core\Url;
 use Drupal\facets\Exception\InvalidQueryTypeException;
 use Drupal\facets\FacetInterface;
 use Drupal\facets\FacetSource\FacetSourcePluginBase;
+use Drupal\facets\FacetSource\SearchApiFacetSourceInterface;
 use Drupal\facets\QueryType\QueryTypePluginManager;
 use Drupal\search_api\Backend\BackendInterface;
 use Drupal\search_api\Display\DisplayPluginManager;
@@ -26,7 +27,7 @@ use Symfony\Component\HttpFoundation\Request;
  *   deriver = "Drupal\facets\Plugin\facets\facet_source\SearchApiDisplayDeriver"
  * )
  */
-class SearchApiDisplay extends FacetSourcePluginBase {
+class SearchApiDisplay extends FacetSourcePluginBase implements SearchApiFacetSourceInterface {
 
   /**
    * The search index the query should is executed on.
@@ -311,12 +312,9 @@ class SearchApiDisplay extends FacetSourcePluginBase {
   }
 
   /**
-   * Retrieves the Search API display plugin associated with this facet source.
-   *
-   * @return \Drupal\search_api\Display\DisplayInterface
-   *   The Search API display plugin associated with this facet source.
+   * {@inheritdoc}
    */
-  protected function getDisplay() {
+  public function getDisplay() {
     return $this->displayPluginManager
       ->createInstance($this->pluginDefinition['display_id']);
   }