diff --git a/core/lib/Drupal/Core/Menu/MenuTreeStorage.php b/core/lib/Drupal/Core/Menu/MenuTreeStorage.php
index f8c9613..2884741 100644
--- a/core/lib/Drupal/Core/Menu/MenuTreeStorage.php
+++ b/core/lib/Drupal/Core/Menu/MenuTreeStorage.php
@@ -269,10 +269,10 @@ public function save(array $link) {
    *   A definition, according to $definitionFields, for a
    *   \Drupal\Core\Menu\MenuLinkInterface plugin.
    *
-   * @return array
+   * @return string[]
    *   The menu names affected by the save operation. This will be one menu
-   *   name if the link is saved to the sane menu, or two if it is saved to a
-   *   new menu.
+   *   name if the link is saved to the same menu, or two if it is saved to a
+   *   new menu. If saving the menu is not necessary, it will be an empty array.
    *
    * @throws \Exception
    *   Thrown if the storage back-end does not exist and could not be created.
@@ -305,7 +305,8 @@ protected function doSave(array $link) {
       // - MenuTreeStorage::preSave() removes the 'mlid' from $fields.
       // - The order of the keys in $original and $fields is different.
       if (array_diff_assoc($fields, $original) == [] && array_diff_assoc($original, $fields) == ['mlid' => $link['mlid']]) {
-        return $affected_menus;
+        // No menus are affected.
+        return [];
       }
       $affected_menus[$original['menu_name']] = $original['menu_name'];
     }
diff --git a/core/lib/Drupal/Core/Menu/MenuTreeStorageInterface.php b/core/lib/Drupal/Core/Menu/MenuTreeStorageInterface.php
index f0c61d0..f001e3f 100644
--- a/core/lib/Drupal/Core/Menu/MenuTreeStorageInterface.php
+++ b/core/lib/Drupal/Core/Menu/MenuTreeStorageInterface.php
@@ -91,16 +91,16 @@ public function loadByRoute($route_name, array $route_parameters = [], $menu_nam
   /**
    * Saves a plugin definition to the storage.
    *
-   * This function can provide optimizations to avoid saves, when there have
-   * been no changes. This should be reflected in the return value.
+   * This function can provide optimizations to avoid saves if there are no
+   * changes. This should be reflected in the return value.
    *
    * @param array $definition
    *   A definition for a \Drupal\Core\Menu\MenuLinkInterface plugin.
    *
    * @return string[]
    *   The menu names affected by the save operation. This will be one menu
-   *   name if the link is saved to the sane menu, or two if it is saved to a
-   *   new menu.
+   *   name if the link is saved to the same menu, or two if it is saved to a
+   *   new menu. If saving the menu is not necessary, it will be an empty array.
    *
    * @throws \Exception
    *   Thrown if the storage back-end does not exist and could not be created.
diff --git a/core/tests/Drupal/KernelTests/Core/Menu/MenuTreeStorageTest.php b/core/tests/Drupal/KernelTests/Core/Menu/MenuTreeStorageTest.php
index b52f646..a758d4f 100644
--- a/core/tests/Drupal/KernelTests/Core/Menu/MenuTreeStorageTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Menu/MenuTreeStorageTest.php
@@ -366,7 +366,7 @@ public function testLoadByProperties() {
 
   /**
    * Tests saving without any changes.
-   */ 
+   */
   public function testResaving() {
     $affected_menus = $this->addMenuLink('root');
     $this->assertEquals(['tools' => 'tools'], $affected_menus);