Issue #2151095 by joelpittet, longwave | Cottser: Convert theme_admin_page() to Twig.

core/modules/system/system.admin.inc

@@ -116,7 +116,9 @@ function template_preprocess_admin_block_content(&$variables) {
 }
 
 /**
- * Returns HTML for an administrative page.
+ * Prepares variables for administrative index page templates.
+ *
+ * Default template: admin-page.html.twig.
  *
  * @param $variables
  *   An associative array containing:
@@ -127,40 +129,24 @@ function template_preprocess_admin_block_content(&$variables) {
  *
  * @ingroup themeable
  */
-function theme_admin_page($variables) {
-  $blocks = $variables['blocks'];
-
-  $stripe = 0;
-  $container = array();
-
-  foreach ($blocks as $block) {
-    $admin_block = array(
-      '#theme' => 'admin_block',
-      '#block' => $block,
+function template_preprocess_admin_page(&$variables) {
+  $variables['system_compact_link'] = array(
+    '#theme' => 'system_compact_link',
   );
-    if ($block_output = drupal_render($admin_block)) {
+  $variables['containers'] = array();
+  $stripe = 0;
+  foreach ($variables['blocks'] as $block) {
+    if (!empty($block['content']['#content'])) {
       if (empty($block['position'])) {
-        // perform automatic striping.
+        // Perform automatic striping.
         $block['position'] = ++$stripe % 2 ? 'left' : 'right';
       }
-      if (!isset($container[$block['position']])) {
-        $container[$block['position']] = '';
-      }
-      $container[$block['position']] .= $block_output;
-    }
+      $variables['containers'][$block['position']]['blocks'][] = array(
+        '#theme' => 'admin_block',
+        '#block' => $block,
+      );
     }
-
-  $system_compact_link = array('#theme' => 'system_compact_link');
-  $output = '<div class="admin clearfix">';
-  $output .= drupal_render($system_compact_link);
-
-  foreach ($container as $id => $data) {
-    $output .= '<div class="' . $id . ' clearfix">';
-    $output .= $data;
-    $output .= '</div>';
   }
-  $output .= '</div>';
-  return $output;
 }
 
 /**

core/modules/system/system.module

@@ -196,6 +196,7 @@ function system_theme() {
     'admin_page' => array(
       'variables' => array('blocks' => NULL),
       'file' => 'system.admin.inc',
+      'template' => 'admin-page',
     ),
     'admin_block' => array(
       'variables' => array('block' => NULL),

core/modules/system/templates/admin-page.html.twig

+{#
+/**
+ * @file
+ * Default theme implementation for an administrative page.
+ *
+ * Available variables:
+ * - system_compact_link: Themed link to toggle compact view.
+ * - containers: An list of administrative blocks keyed by position: left or
+ *   right. Contains:
+ *   - blocks: A list of blocks within a container.
+ *
+ * @see template_preprocess_admin_page()
+ *
+ * @ingroup themeable
+ */
+#}
+<div class="admin clearfix">
+  {{ system_compact_link }}
+  {% for position, container in containers %}
+    <div class="{{ position }} clearfix">
+      {% for block in container.blocks %}
+        {{ block }}
+      {% endfor %}
+    </div>
+  {% endfor %}
+</div>