Issue #2355245 by amateescu: ER's label formatter needs to take into account...

Issue #2355245 by amateescu: ER's label formatter needs to take into account that $entity->urlInfo() might throw an exception

core/modules/entity_reference/src/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatter.php

@@ -8,6 +8,7 @@
 namespace Drupal\entity_reference\Plugin\Field\FieldFormatter;
 
 use Drupal\Component\Utility\String;
+use Drupal\Core\Entity\Exception\UndefinedLinkTemplateException;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
 
@@ -61,12 +62,26 @@ public function settingsSummary() {
    */
   public function viewElements(FieldItemListInterface $items) {
     $elements = array();
+    $output_as_link = $this->getSetting('link');
 
     foreach ($this->getEntitiesToView($items) as $delta => $entity) {
       $label = $entity->label();
       // If the link is to be displayed and the entity has a uri, display a
       // link.
-      if ($this->getSetting('link') && !$entity->isNew() && $uri = $entity->urlInfo()) {
+      if ($output_as_link && !$entity->isNew()) {
+        try {
+          $uri = $entity->urlInfo();
+        }
+        catch (UndefinedLinkTemplateException $e) {
+          // This exception is thrown by \Drupal\Core\Entity\Entity::urlInfo()
+          // and it means that the entity type doesn't have a link template nor
+          // a valid "uri_callback", so don't bother trying to output a link for
+          // the rest of the referenced entities.
+          $output_as_link = FALSE;
+        }
+      }
+
+      if ($output_as_link && isset($uri) && !$entity->isNew()) {
         $elements[$delta] = [
           '#type' => 'link',
           '#title' => $label,

core/modules/entity_reference/src/Tests/EntityReferenceFormatterTest.php

@@ -9,6 +9,7 @@
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\filter\Entity\FilterFormat;
 use Drupal\system\Tests\Entity\EntityUnitTestBase;
 
@@ -226,6 +227,21 @@ public function testLabelFormatter() {
     $build = $this->buildRenderArray([$this->referencedEntity, $this->unsavedReferencedEntity], $formatter, array('link' => FALSE));
     $this->assertEqual($build[0]['#markup'], $this->referencedEntity->label(), sprintf('The markup returned by the %s formatter is correct for an item with a saved entity.', $formatter));
     $this->assertEqual($build[1]['#markup'], $this->unsavedReferencedEntity->label(), sprintf('The markup returned by the %s formatter is correct for an item with a unsaved entity.', $formatter));
+
+    // Test an entity type that doesn't have any link templates, which means
+    // \Drupal\Core\Entity\EntityInterface::urlInfo() will throw an exception
+    // and the label formatter will output only the label instead of a link.
+    $field_storage_config = FieldStorageConfig::loadByName($this->entityType, $this->fieldName);
+    $field_storage_config->settings['target_type'] = 'entity_test_label';
+    $field_storage_config->save();
+
+    $referenced_entity_with_no_link_template = entity_create('entity_test_label', array(
+      'name' => $this->randomMachineName(),
+    ));
+    $referenced_entity_with_no_link_template->save();
+
+    $build = $this->buildRenderArray([$referenced_entity_with_no_link_template], $formatter, array('link' => TRUE));
+    $this->assertEqual($build[0]['#markup'], $referenced_entity_with_no_link_template->label(), sprintf('The markup returned by the %s formatter is correct for an entity type with no valid link template.', $formatter));
   }
 
   /**