Issue #2506151 by joelpittet, Cottser, lauriii, Lukas von Blarer, tim.plunkett: Make the Twig extension link() accept Attribute objects

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

@@ -43,10 +43,11 @@ use Drupal\Component\Utility\SafeStringInterface;
  * htmlspecialchars() and the entire attribute string is marked safe for output.
  */
 class Attribute implements \ArrayAccess, \IteratorAggregate, SafeStringInterface {
+
   /**
    * Stores the attribute data.
    *
-   * @var array
+   * @var \Drupal\Core\Template\AttributeValueBase[]
    */
   protected $storage = array();
 
@@ -261,6 +262,21 @@ class Attribute implements \ArrayAccess, \IteratorAggregate, SafeStringInterface
     return $return;
   }
 
+  /**
+   * Returns all storage elements as an array.
+   *
+   * @return array
+   *   An associative array of attributes.
+   */
+  public function toArray() {
+    $return = [];
+    foreach ($this->storage as $name => $value) {
+      $return[$name] = $value->value();
+    }
+
+    return $return;
+  }
+
   /**
    * Implements the magic __clone() method.
    */

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

@@ -260,17 +260,20 @@ class TwigExtension extends \Twig_Extension {
    *   The link text for the anchor tag as a translated string.
    * @param \Drupal\Core\Url|string $url
    *   The URL object or string used for the link.
-   * @param array $attributes
-   *   An optional array of link attributes.
+   * @param array|\Drupal\Core\Template\Attribute $attributes
+   *   An optional array or Attribute object of link attributes.
    *
    * @return array
    *   A render array representing a link to the given URL.
    */
-  public function getLink($text, $url, array $attributes = []) {
+  public function getLink($text, $url, $attributes = []) {
     if (!$url instanceof Url) {
       $url = Url::fromUri($url);
     }
     if ($attributes) {
+      if ($attributes instanceof Attribute) {
+        $attributes = $attributes->toArray();
+      }
       if ($existing_attributes = $url->getOption('attributes')) {
         $attributes = array_merge($existing_attributes, $attributes);
       }

core/modules/system/src/Tests/Theme/EngineTwigTest.php

@@ -85,6 +85,7 @@ class EngineTwigTest extends WebTestBase {
       'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['absolute' => TRUE, 'attributes' => ['foo' => 'bar']])),
       'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['foo' => 'bar', 'id' => 'kitten']])),
       'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['id' => 'kitten']])),
+      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['class' => ['llama', 'kitten', 'panda']]])),
     ];
 
     // Verify that link() has the ability to bubble cacheability metadata:

core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\twig_theme_test;
 
+use Drupal\Core\Template\Attribute;
 use Drupal\Core\Url;
 
 /**
@@ -53,11 +54,14 @@ class TwigThemeTestController {
    * Renders for testing link_generator functions in a Twig template.
    */
   public function linkGeneratorRender() {
-    return array(
+    return [
       '#theme' => 'twig_theme_test_link_generator',
       '#test_url' => new Url('user.register', [], ['absolute' => TRUE]),
       '#test_url_attribute' => new Url('user.register', [], ['attributes' => ['foo' => 'bar']]),
-    );
+      // Explicitly creating an Attribute object to avoid false positives when
+      // testing Attribute object merging with the twig link() function.
+      '#attributes' => new Attribute(['class' => ['llama', 'kitten', 'panda']]),
+    ];
   }
 
   /**

core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.link_generator.html.twig

@@ -2,3 +2,4 @@
 <div>link via the linkgenerator: {{ link('register', test_url, {'foo': 'bar'}) }}</div>
 <div>link via the linkgenerator: {{ link('register', test_url_attribute, {'id': 'kitten'}) }}</div>
 <div>link via the linkgenerator: {{ link('register', 'route:user.register', {'id': 'kitten'}) }}</div>
+<div>link via the linkgenerator: {{ link('register', 'route:user.register', attributes) }}</div>

core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module

@@ -43,7 +43,11 @@ function twig_theme_test_theme($existing, $type, $theme, $path) {
     'template' => 'twig_theme_test.url_generator',
   );
   $items['twig_theme_test_link_generator'] = array(
-    'variables' => array('test_url' => NULL, 'test_url_attribute' => NULL),
+    'variables' => [
+      'test_url' => NULL,
+      'test_url_attribute' => NULL,
+      'attributes' => [],
+    ],
     'template' => 'twig_theme_test.link_generator',
   );
   $items['twig_theme_test_url_to_string'] = array(