Issue #3059387 by b_sharpe, AaronChristian: Taxonomy Terms cannot be rendered...

Issue #3059387 by b_sharpe, AaronChristian: Taxonomy Terms cannot be rendered when in preview: EntityMalformedException

core/modules/rdf/rdf.module

@@ -567,7 +567,7 @@ function rdf_preprocess_taxonomy_term(&$variables) {
   $term = $variables['term'];
   $mapping = rdf_get_mapping('taxonomy_term', $term->bundle());
   $bundle_mapping = $mapping->getPreparedBundleMapping();
-  $variables['attributes']['about'] = $term->toUrl()->toString();
+  $variables['attributes']['about'] = $variables['url'];
   $variables['attributes']['typeof'] = empty($bundle_mapping['types']) ? NULL : $bundle_mapping['types'];
 
   // Add RDFa markup for the taxonomy term name as metadata, if present.

core/modules/taxonomy/taxonomy.module

@@ -153,7 +153,7 @@ function template_preprocess_taxonomy_term(&$variables) {
   /** @var \Drupal\taxonomy\TermInterface $term */
   $term = $variables['term'];
 
-  $variables['url'] = $term->toUrl()->toString();
+  $variables['url'] = !$term->isNew() ? $term->toUrl()->toString() : NULL;
 
   // Make name field available separately.  Skip this custom preprocessing if
   // the field display is configurable and skipping has been enabled.

core/modules/taxonomy/tests/src/Kernel/TermKernelTest.php

@@ -145,4 +145,27 @@ public function testTaxonomyVocabularyTree() {
     $this->assertEqual(5, count($ancestors), 'The term has five ancestors including the term itself.');
   }
 
+  /**
+   * Tests that a Term is renderable when unsaved (preview).
+   */
+  public function testTermPreview() {
+    $entity_manager = \Drupal::entityTypeManager();
+    $vocabulary = $this->createVocabulary();
+
+    // Create a unsaved term.
+    $term = $entity_manager->getStorage('taxonomy_term')->create([
+      'vid' => $vocabulary->id(),
+      'name' => 'Inator',
+    ]);
+
+    // Confirm we can get the view of unsaved term.
+    $render_array = $entity_manager->getViewBuilder('taxonomy_term')
+      ->view($term);
+    $this->assertTrue(!empty($render_array), 'Term view builder is built.');
+
+    // Confirm we can render said view.
+    $rendered = \Drupal::service('renderer')->renderPlain($render_array);
+    $this->assertTrue(!empty(trim($rendered)), 'Term is able to be rendered.');
+  }
+
 }