Issue #1939066 by joelpittet, chrisjlee, Cottser, splatio, jenlampton: Convert theme_breadcrumb() to Twig.

core/includes/theme.inc

@@ -1835,27 +1835,6 @@ function theme_image($variables) {
   return '<img' . new Attribute($attributes) . ' />';
 }
 
-/**
- * Returns HTML for a breadcrumb trail.
- *
- * @param $variables
- *   An associative array containing:
- *   - breadcrumb: An array containing the breadcrumb links.
- */
-function theme_breadcrumb($variables) {
-  $breadcrumb = $variables['breadcrumb'];
-  $output = '';
-  if (!empty($breadcrumb)) {
-    $output .= '<nav role="navigation" class="breadcrumb">';
-    // Provide a navigational heading to give context for breadcrumb links to
-    // screen-reader users. Make the heading invisible with .visually-hidden.
-    $output .= '<h2 class="visually-hidden">' . t('You are here') . '</h2>';
-    $output .= '<ol><li>' . implode('</li><li>', $breadcrumb) . '</li></ol>';
-    $output .= '</nav>';
-  }
-  return $output;
-}
-
 /**
  * #pre_render callback to transform children of an element into #rows suitable for theme_table().
  *
@@ -3146,6 +3125,7 @@ function drupal_common_theme() {
     ),
     'breadcrumb' => array(
       'variables' => array('breadcrumb' => NULL),
+      'template' => 'breadcrumb',
     ),
     'table' => array(
       'variables' => array('header' => NULL, 'rows' => NULL, 'attributes' => array(), 'caption' => NULL, 'colgroups' => array(), 'sticky' => TRUE, 'responsive' => TRUE, 'empty' => ''),

core/modules/system/templates/breadcrumb.html.twig

@@ -0,0 +1,23 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a breadcrumb trail.
+ *
+ * Available variables:
+ * - breadcrumb: Breadcrumb trail items.
+ *
+ * @see template_preprocess()
+ *
+ * @ingroup themeable
+ */
+#}
+{% if breadcrumb %}
+  <nav class="breadcrumb" role="navigation">
+    <h2 class="visually-hidden">{{ 'You are here'|t }}</h2>
+    <ol>
+    {% for item in breadcrumb %}
+      <li>{{ item }}</li>
+    {% endfor %}
+    </ol>
+  </nav>
+{% endif %}