Issue #2605420 by IRuslan, joelpittet: Missing aria-pressed template_preprocess_details() due to lost copied attributes in Attribute

core/lib/Drupal/Core/Template/Attribute.php

@@ -117,10 +117,11 @@ class Attribute implements \ArrayAccess, \IteratorAggregate, MarkupInterface {
    *   An AttributeValueBase representation of the attribute's value.
    */
   protected function createAttributeValue($name, $value) {
-    // If the value is already an AttributeValueBase object, return it
+    // If the value is already an AttributeValueBase object,
-    // straight away.
+    // return a new instance of the same class, but with the new name.
     if ($value instanceof AttributeValueBase) {
-      return $value;
+      $class = get_class($value);
+      return new $class($name, $value->value());
     }
     // An array value or 'class' attribute name are forced to always be an
     // AttributeArray value for consistency.

core/tests/Drupal/Tests/Core/Common/AttributesTest.php

@@ -71,4 +71,20 @@ class AttributesTest extends UnitTestCase {
     }
   }
 
+  /**
+   * Test AttributeValueBase copy.
+   */
+  public function testAttributeValueBaseCopy() {
+    $original_attributes = new Attribute([
+      'checked' => TRUE,
+      'class' => ['who', 'is', 'on'],
+      'id' => 'first',
+    ]);
+    $attributes['selected'] = $original_attributes['checked'];
+    $attributes['id'] = $original_attributes['id'];
+    $attributes = new Attribute($attributes);
+    $this->assertSame((string) $original_attributes, ' checked class="who is on" id="first"', 'Original boolean value used with original name.');
+    $this->assertSame((string) $attributes, ' selected id="first"', 'Original boolean value used with new name.');
+  }
+
 }