Issue #2083835 by yched: Fixed theme('field') displays no value on empty...

Issue #2083835 by yched: Fixed theme('field') displays no value on empty fields even if the formatter returned an output.

core/modules/field/field.module

@@ -817,14 +817,15 @@ function template_preprocess_field(&$variables, $hook) {
 
   // We want other preprocess functions and the theme implementation to have
   // fast access to the field item render arrays. The item render array keys
-  // (deltas) should always be a subset of the keys in #items, and looping on
-  // those keys is faster than calling element_children() or looping on all keys
-  // within $element, since that requires traversal of all element properties.
+  // (deltas) should always be numerically indexed starting from 0, and looping
+  // on those keys is faster than calling element_children() or looping on all
+  // keys within $element, since that requires traversal of all element
+  // properties.
   $variables['items'] = array();
-  foreach ($element['#items'] as $delta => $item) {
-    if (!empty($element[$delta])) {
-      $variables['items'][$delta] = $element[$delta];
-    }
+  $delta = 0;
+  while (!empty($element[$delta])) {
+    $variables['items'][$delta] = $element[$delta];
+    $delta++;
   }
 
   // Add default CSS classes. Since there can be many fields rendered on a page,

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/field/formatter/TestFieldEmptyFormatter.php

@@ -29,25 +29,17 @@
  */
 class TestFieldEmptyFormatter extends FormatterBase {
 
-  /**
-   * {@inheritdoc}
-   */
-  public function prepareView(array $entities, $langcode, array $items) {
-    foreach ($entities as $id => $entity) {
-      if ($items[$id]->isEmpty()) {
-        // For fields with no value, just add the configured "empty" value.
-        $items[$id][0]->value = $this->getSetting('test_empty_string');
-      }
-    }
-  }
-
   /**
    * {@inheritdoc}
    */
   public function viewElements(EntityInterface $entity, $langcode, FieldInterface $items) {
     $elements = array();
 
-    if (!empty($items)) {
+    if ($items->isEmpty()) {
+      // For fields with no value, just add the configured "empty" value.
+      $elements[0] = array('#markup' => $this->getSetting('test_empty_string'));
+    }
+    else {
       foreach ($items as $delta => $item) {
         // This formatter only needs to output raw for testing.
         $elements[$delta] = array('#markup' => $item->value);