Issue #3245553 by quietone, danflanagan8: Fix migration of localized D6 menu links

core/modules/content_translation/migrations/d6_menu_links_localized.yml

+id: d6_menu_links_localized
+label: Menu links localized
+migration_tags:
+  - Drupal 6
+  - Content
+  - Multilingual
+source:
+  plugin: menu_link
+  constants:
+    bundle: menu_link_content
+process:
+  skip_not_localized:
+    plugin: skip_on_empty
+    source: is_localized
+    method: row
+  id: mlid
+  title: link_title
+  description: description
+  langcode: language
+  menu_name:
+    -
+      plugin: migration_lookup
+      # The menu migration is in the system module.
+      migration: d6_menu
+      source: menu_name
+    -
+      plugin: skip_on_empty
+      method: row
+    -
+      plugin: static_map
+      map:
+        management: admin
+      bypass: true
+  'link/uri':
+    plugin: link_uri
+    source: link_path
+  'link/options':
+    plugin: link_options
+    source: options
+  route:
+    plugin: route
+    source:
+      - link_path
+      - options
+  route_name: '@route/route_name'
+  route_parameters: '@route/route_parameters'
+  url: '@route/url'
+  options: '@route/options'
+  external: external
+  weight: weight
+  expanded: expanded
+  enabled: enabled
+  parent:
+    plugin: menu_link_parent
+    source:
+      - plid
+      - '@menu_name'
+      - parent_link_path
+  changed: updated
+destination:
+  plugin: entity:menu_link_content
+  no_stub: true
+  translations: true
+  destination_module: content_translation
+migration_dependencies:
+  required:
+    - language
+    - d6_language_content_menu_settings
+    - d6_menu_links

core/modules/menu_link_content/migrations/d6_menu_links.yml

@@ -7,6 +7,14 @@ migration_tags:
 source:
   plugin: menu_link
 process:
+  skip_localized:
+    -
+      plugin: callback
+      callable: is_null
+      source: is_localized
+    -
+      plugin: skip_on_empty
+      method: row
   id: mlid
   title: link_title
   description: description

core/modules/menu_link_content/src/Plugin/migrate/source/MenuLink.php

@@ -141,6 +141,20 @@ public function prepareRow(Row $row) {
         $row->setSourceProperty('skip_translation', FALSE);
       }
     }
+    // In Drupal 6 the language for the menu is in the options array. Set
+    // property 'is_localized' so that the process pipeline can determine if
+    // the menu link is localize or not.
+    $row->setSourceProperty('is_localized', NULL);
+    $default_language = $this->variableGet('language_default', (object) ['language' => 'und']);
+    $default_language = $default_language->language;
+    $options = unserialize($row->getSourceProperty('options'));
+    if (isset($options['langcode'])) {
+      if ($options['langcode'] != $default_language) {
+        $row->setSourceProperty('language', $options['langcode']);
+        $row->setSourceProperty('is_localized', 'localized');
+      }
+    }
+
     $row->setSourceProperty('options', unserialize($row->getSourceProperty('options')));
     $row->setSourceProperty('enabled', !$row->getSourceProperty('hidden'));
     $description = $row->getSourceProperty('options/attributes/title');

core/modules/menu_link_content/tests/src/Kernel/Migrate/d6/MigrateMenuLinkLocalizedTest.php

+<?php
+
+namespace Drupal\Tests\menu_link_content\Kernel\Migrate\d6;
+
+use Drupal\Tests\menu_link_content\Kernel\Migrate\MigrateMenuLinkTestTrait;
+use Drupal\Tests\node\Kernel\Migrate\d6\MigrateNodeTestBase;
+use Drupal\Tests\user\Traits\UserCreationTrait;
+
+/**
+ * Tests Menu link localized translation migration.
+ *
+ * @group migrate_drupal_6
+ */
+class MigrateMenuLinkLocalizedTest extends MigrateNodeTestBase {
+
+  use MigrateMenuLinkTestTrait;
+  use UserCreationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'content_translation',
+    'language',
+    'link',
+    'menu_link_content',
+    'menu_ui',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->setUpCurrentUser();
+    $this->installEntitySchema('menu_link_content');
+    $this->executeMigrations([
+      'language',
+      'd6_language_content_menu_settings',
+      'd6_menu',
+      'd6_menu_links',
+      'd6_menu_links_localized',
+    ]);
+  }
+
+  /**
+   * Tests migration of menu link localized translations.
+   */
+  public function testMenuLinkLocalized() {
+    // A localized menu link.
+    $this->assertEntity('463', 'fr', 'fr - Test 1', 'secondary-links', 'fr - Test menu link 1', TRUE, FALSE, [
+      'attributes' => ['title' => 'fr - Test menu link 1'],
+      'langcode' => 'fr',
+      'alter' => TRUE,
+    ], 'internal:/user/login', -49, 0);
+  }
+
+}

core/modules/menu_link_content/tests/src/Kernel/Migrate/d6/MigrateMenuLinkTest.php

@@ -98,9 +98,6 @@ public function testMenuLinks() {
     $this->assertEntity('460', 'Le Vrai McCoy', 'primary-links', NULL, TRUE, FALSE, ['attributes' => ['title' => ''], 'alter' => TRUE], 'entity:node/10', 0);
     $this->assertEntity('461', 'Abantu zulu', 'primary-links', NULL, TRUE, FALSE, ['attributes' => ['title' => ''], 'alter' => TRUE], 'entity:node/12', 0);
     $this->assertEntity('462', 'The Zulu People', 'primary-links', NULL, TRUE, FALSE, ['attributes' => ['title' => ''], 'alter' => TRUE], 'entity:node/12', 0);
-
-    // Test the migration of menu links translation.
-    $this->assertEntity('463', 'fr - Test 1', 'secondary-links', 'fr - Test menu link 1', TRUE, FALSE, ['attributes' => ['title' => 'fr - Test menu link 1'], 'langcode' => 'fr', 'alter' => TRUE], 'internal:/user/login', -49);
   }
 
 }

core/modules/menu_link_content/tests/src/Kernel/Migrate/d6/MigrateMenuLinkTranslationTest.php

@@ -78,24 +78,6 @@ public function testMenuLinks() {
     $this->assertSame(['attributes' => ['title' => '']], $menu_link->link->options);
     $this->assertSame('https://www.drupal.org', $menu_link->link->uri);
     $this->assertSame(-50, $menu_link->getWeight());
-
-    $menu_link = MenuLinkContent::load(463);
-    $this->assertInstanceOf(MenuLinkContent::class, $menu_link);
-    $this->assertSame('fr - Test 1', $menu_link->getTitle());
-    $this->assertSame('fr - Test menu link 1', $menu_link->getDescription());
-    $this->assertSame('secondary-links', $menu_link->getMenuName());
-    $this->assertTrue($menu_link->isEnabled());
-    $this->assertFalse($menu_link->isExpanded());
-    $attributes = [
-      'attributes' => [
-        'title' => 'fr - Test menu link 1',
-      ],
-      'langcode' => 'fr',
-      'alter' => TRUE,
-    ];
-    $this->assertSame($attributes, $menu_link->link->options);
-    $this->assertSame('internal:/user/login', $menu_link->link->uri);
-    $this->assertSame(-49, $menu_link->getWeight());
   }
 
 }