From 6fb16bc30f2efb63e9033d89d7d7a60d663480f8 Mon Sep 17 00:00:00 2001
From: Anton <info@ensostudio.ru>
Date: Mon, 27 Dec 2021 21:44:48 +0300
Subject: [PATCH] Fix #19098: Add
 `yii\helper\BaseHtml::$normalizeClassAttribute` to fix duplicate classes

---
 framework/CHANGELOG.md               |  1 +
 framework/helpers/BaseHtml.php       | 18 +++++++++++++++---
 tests/framework/helpers/HtmlTest.php |  4 +++-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 722a7e90e23..626950422eb 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -36,6 +36,7 @@ Yii Framework 2 Change Log
 - Bug #19031: Fix displaying console help for parameters with declared types (WinterSilence)
 - Bug #19030: Add DI container usage to `yii\base\Widget::end()` (papppeter)
 - Bug #19096: Fix `Request::getIsConsoleRequest()` may return erroneously when testing a Web application in Codeception (WinterSilence)
+- Enh #19098: Add `yii\helper\BaseHtml::$normalizeClassAttribute` to fix duplicate classes (WinterSilence)
 - Enh #19108: Optimize `Component::hasEventHandlers()` and `Component::trigger()` (WinterSilence)
 
 
diff --git a/framework/helpers/BaseHtml.php b/framework/helpers/BaseHtml.php
index 5d89314971f..156e34fe97e 100644
--- a/framework/helpers/BaseHtml.php
+++ b/framework/helpers/BaseHtml.php
@@ -94,8 +94,15 @@ class BaseHtml
      * @since 2.0.3
      */
     public static $dataAttributes = ['aria', 'data', 'data-ng', 'ng'];
-
-
+    /**
+     * @var bool whether to removes duplicate class names in tag attribute `class`
+     * @see mergeCssClasses()
+     * @see renderTagAttributes()
+     * @since 2.0.44
+     */
+    public static $normalizeClassAttribute = false;
+    
+    
     /**
      * Encodes special characters into HTML entities.
      * The [[\yii\base\Application::charset|application charset]] will be used for encoding.
@@ -1981,6 +1988,11 @@ public static function renderTagAttributes($attributes)
                     if (empty($value)) {
                         continue;
                     }
+                    if (static::$normalizeClassAttribute === true && count($value) > 1) {
+                        // removes duplicate classes
+                        $value = explode(' ', implode(' ', $value));
+                        $value = array_unique($value);
+                    }
                     $html .= " $name=\"" . static::encode(implode(' ', $value)) . '"';
                 } elseif ($name === 'style') {
                     if (empty($value)) {
@@ -2047,7 +2059,7 @@ private static function mergeCssClasses(array $existingClasses, array $additiona
             }
         }
 
-        return array_unique($existingClasses);
+        return static::$normalizeClassAttribute ? array_unique($existingClasses) : $existingClasses;
     }
 
     /**
diff --git a/tests/framework/helpers/HtmlTest.php b/tests/framework/helpers/HtmlTest.php
index 5b2c9de0090..3dfd9f83345 100644
--- a/tests/framework/helpers/HtmlTest.php
+++ b/tests/framework/helpers/HtmlTest.php
@@ -1082,12 +1082,14 @@ public function testRenderOptions()
         $this->assertEqualsWithoutLE($expected, Html::renderSelectOptions(['1.10'], $data, $attributes));
     }
 
-    public function testRenderAttributes()
+    public function testRenderTagAttributes()
     {
         $this->assertEquals('', Html::renderTagAttributes([]));
         $this->assertEquals(' name="test" value="1&lt;&gt;"', Html::renderTagAttributes(['name' => 'test', 'empty' => null, 'value' => '1<>']));
         $this->assertEquals(' checked disabled', Html::renderTagAttributes(['checked' => true, 'disabled' => true, 'hidden' => false]));
         $this->assertEquals(' class="first second"', Html::renderTagAttributes(['class' => ['first', 'second']]));
+        Html::$normalizeClassAttribute = true;
+        $this->assertEquals(' class="first second"', Html::renderTagAttributes(['class' => ['first second', 'first']]));
         $this->assertEquals('', Html::renderTagAttributes(['class' => []]));
         $this->assertEquals(' style="width: 100px; height: 200px;"', Html::renderTagAttributes(['style' => ['width' => '100px', 'height' => '200px']]));
         $this->assertEquals('', Html::renderTagAttributes(['style' => []]));