Fixes #4318: `yii\helpers\Html::ul()` and `ol()` will return an empty list tag…

framework/CHANGELOG.md

@@ -177,6 +177,7 @@ Yii Framework 2 Change Log
 - Chg #4147: `BaseMailer::compose()` will not overwrite the `message` parameter if it is explicitly provided (qiangxue)
 - Chg #4201: change default value of `SyslogTarget::facility` from LOG_SYSLOG to LOG_USER (dizews)
 - Chg #4227: `\yii\widgets\LinkPager::$hideOnSinglePage` is now `true` by default (samdark)
+- Chg #4318: `yii\helpers\Html::ul()` and `ol()` will return an empty list tag if an empty item array is given (qiangxue)
 - Chg: Replaced `clearAll()` and `clearAllAssignments()` in `yii\rbac\ManagerInterface` with `removeAll()`, `removeAllRoles()`, `removeAllPermissions()`, `removeAllRules()` and `removeAllAssignments()` (qiangxue)
 - Chg: Added `$user` as the first parameter of `yii\rbac\Rule::execute()` (qiangxue)
 - Chg: `yii\grid\DataColumn::getDataCellValue()` visibility is now `public` to allow accessing the value from a GridView directly (cebe)

framework/helpers/BaseHtml.php

@@ -976,18 +976,20 @@ class BaseHtml
      *
      * See [[renderTagAttributes()]] for details on how attributes are being rendered.
      *
-     * @return string the generated unordered list. An empty string is returned if `$items` is empty.
+     * @return string the generated unordered list. An empty list tag will be returned if `$items` is empty.
      */
     public static function ul($items, $options = [])
     {
-        if (empty($items)) {
-            return '';
-        }
         $tag = isset($options['tag']) ? $options['tag'] : 'ul';
         $encode = !isset($options['encode']) || $options['encode'];
         $formatter = isset($options['item']) ? $options['item'] : null;
         $itemOptions = isset($options['itemOptions']) ? $options['itemOptions'] : [];
         unset($options['tag'], $options['encode'], $options['item'], $options['itemOptions']);
+
+        if (empty($items)) {
+            return static::tag($tag, '', $options);
+        }
+
         $results = [];
         foreach ($items as $index => $item) {
             if ($formatter !== null) {

tests/unit/framework/helpers/HtmlTest.php

@@ -439,6 +439,8 @@ EOD;
                 return "<li class=\"item-$index\">$item</li>";
             }
         ]));
+
+        $this->assertEquals('<ul class="test"></ul>', Html::ul([], ['class' => 'test']));
     }
 
     public function testOl()
@@ -469,6 +471,8 @@ EOD;
                 return "<li class=\"item-$index\">$item</li>";
             }
         ]));
+
+        $this->assertEquals('<ol class="test"></ol>', Html::ol([], ['class' => 'test']));
     }
 
     public function testRenderOptions()