Issue #3296086 by Spokje, catch, smustgrave, xjm: Deprecate/remove js-cookie dependency

core/core.libraries.yml

@@ -911,3 +911,4 @@ js-cookie:
     gpl-compatible: true
   js:
     assets/vendor/js-cookie/js.cookie.min.js: {}
+  deprecated: The %library_id% asset library is deprecated in Drupal 10.1.0 and will be removed in Drupal 11.0.0. There is no replacement. See https://www.drupal.org/node/3322720

core/tests/Drupal/KernelTests/Core/Asset/DeprecatedAssetsTest.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace Drupal\KernelTests\Core\Asset;
+
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Checks the status and definition contents of deprecated libraries.
+ *
+ * @group Asset
+ * @group legacy
+ */
+class DeprecatedAssetsTest extends KernelTestBase {
+
+  /**
+   * Confirms the status and definition contents of deprecated libraries.
+   *
+   * @param string $extension
+   *   The name of the extension that registered a library.
+   * @param string $name
+   *   The name of a registered library to retrieve.
+   * @param string $deprecation_suffix
+   *   The part of the deprecation message after the extension/name.
+   * @param string $expected_hashed_library_definition
+   *   The expected MD5 hash of the library.
+   *
+   * @dataProvider deprecatedLibrariesProvider
+   */
+  public function testDeprecatedLibraries(string $extension, string $name, string $deprecation_suffix, string $expected_hashed_library_definition): void {
+    /** @var \Drupal\Core\Asset\LibraryDiscoveryInterface $library_discovery */
+    $library_discovery = $this->container->get('library.discovery');
+
+    // DrupalCI uses a precision of 100 in certain environments which breaks
+    // this test.
+    ini_set('serialize_precision', -1);
+
+    $this->expectDeprecation("The $extension/$name " . $deprecation_suffix);
+    $library_definition = $library_discovery->getLibraryByName($extension, $name);
+    $this->assertEquals($expected_hashed_library_definition, md5(serialize($library_definition)));
+  }
+
+  /**
+   * The data provider for testDeprecatedLibraries.
+   *
+   * Returns an array in the form of
+   * @code
+   *  [
+   *    (string) description => [
+   *      (string) extension - The name of the extension that registered a library, usually 'core'
+   *      (string) name - The name of a registered library
+   *      (string) deprecation_suffix - The part of the deprecation message after the extension/name
+   *      (string) expected_hashed_library_definition -  The expected MD5 hash of the library
+   *    ]
+   *  ]
+   * @endcode
+   *
+   * @return array
+   *   See description above.
+   */
+  public function deprecatedLibrariesProvider(): array {
+    return [
+      'Tests deprecation of library core/js-cookie' => [
+        'core',
+        'js-cookie',
+        'asset library is deprecated in Drupal 10.1.0 and will be removed in Drupal 11.0.0. There is no replacement. See https://www.drupal.org/node/3322720',
+        '07ce73936a26710db875a3e9ee70cd6e',
+      ],
+    ];
+  }
+
+}