test: Add verification for attribute refresh() method after promoting node to root in NestedSetsBehaviorTest.

src/NestedSetsBehavior.php

@@ -809,15 +809,17 @@ public function leaves(): ActiveQuery
      * Sets the internal operation state to {@see self::OPERATION_MAKE_ROOT} and triggers the save process on the owner
      * model.
      *
-     * - If the attached {@see ActiveRecord} is a new record, this method creates it as the root node of a new tree.
+     * - If the attached {@see ActiveRecord} is a new record, this method creates it as the root node of a new tree,
+     *   setting `left=1`, `right=2`, and `depth=0`.
      * - If the record already exists, it moves the node to become the root node, updating the nested set structure
-     *   accordingly.
+     *   accordingly and adjusting all affected nodes in the tree.
      *
      * This operation is essential for initializing or reorganizing hierarchical data structures, such as category
      * trees, where nodes can be promoted to root status or new trees can be started.
      *
      * The actual creation or movement is performed by saving the owner model, which triggers the appropriate lifecycle
-     * events and updates the tree structure.
+     * events and updates the tree structure. Upon successful save, the model is automatically refreshed to ensure all
+     * nested set attributes reflect their current database values.
      *
      * @param bool $runValidation Whether to perform validation before saving the record.
      * @param array|null $attributes List of attributes that need to be saved. Defaults to `null`, meaning all
@@ -829,7 +831,13 @@ public function leaves(): ActiveQuery
      *
      * Usage example:
      * ```php
+     * // Create a new root node
+     * $category = new Category(['name' => 'Electronics']);
      * $category->makeRoot();
+     *
+     * // Move existing node to become root
+     * $existingNode = Category::findOne(5);
+     * $existingNode->makeRoot();
      * ```
      *
      * @phpstan-param array<string, mixed>|null $attributes
@@ -838,7 +846,15 @@ public function makeRoot(bool $runValidation = true, array|null $attributes = nu
     {
         $this->operation = self::OPERATION_MAKE_ROOT;
 
-        return $this->getOwner()->save($runValidation, $attributes);
+        $owner = $this->getOwner();
+
+        $result = $owner->save($runValidation, $attributes);
+
+        if ($result === true) {
+            $owner->refresh();
+        }
+
+        return $result;
     }
 
     /**

tests/NestedSetsBehaviorTest.php

@@ -2322,4 +2322,135 @@ public function testChildrenMethodRequiresOrderByForCorrectTreeTraversal(): void
             }
         }
     }
+
+    public function testMakeRootRefreshIsNecessaryForCorrectAttributeValues(): void
+    {
+        $this->createDatabase();
+
+        $root = new MultipleTree(['name' => 'Original Root']);
+
+        $root->makeRoot();
+
+        $child1 = new MultipleTree(['name' => 'Child 1']);
+
+        $child1->appendTo($root);
+
+        $child2 = new MultipleTree(['name' => 'Child 2']);
+
+        $child2->appendTo($root);
+
+        $grandchild = new MultipleTree(['name' => 'Grandchild']);
+
+        $grandchild->appendTo($child1);
+
+        $nodeToPromote = MultipleTree::findOne($child1->id);
+
+        self::assertNotNull(
+            $nodeToPromote,
+            'Child node should exist before promoting to root.',
+        );
+        self::assertFalse(
+            $nodeToPromote->isRoot(),
+            "Node should not be root before 'makeRoot()' operation.",
+        );
+
+        $originalLeft = $nodeToPromote->getAttribute('lft');
+        $originalRight = $nodeToPromote->getAttribute('rgt');
+        $originalDepth = $nodeToPromote->getAttribute('depth');
+        $originalTree = $nodeToPromote->getAttribute('tree');
+
+        $result = $nodeToPromote->makeRoot();
+
+        self::assertTrue(
+            $result,
+            "'makeRoot()' should return 'true' when converting node to root.",
+        );
+        self::assertTrue(
+            $nodeToPromote->isRoot(),
+            "Node should be identified as root after 'makeRoot()' - this requires 'refresh()' to work.",
+        );
+        self::assertEquals(
+            1,
+            $nodeToPromote->getAttribute('lft'),
+            "Root node left value should be '1' after 'makeRoot()' - requires 'refresh()' to see updated value.",
+        );
+        self::assertEquals(
+            4,
+            $nodeToPromote->getAttribute('rgt'),
+            "Root node right value should be '4' after 'makeRoot()' - requires 'refresh()' to see updated value.",
+        );
+        self::assertEquals(
+            0,
+            $nodeToPromote->getAttribute('depth'),
+            "Root node depth should be '0' after 'makeRoot()' - requires 'refresh()' to see updated value.",
+        );
+        self::assertEquals(
+            $nodeToPromote->getAttribute('id'),
+            $nodeToPromote->getAttribute('tree'),
+            "Tree attribute should equal node ID for new root - requires 'refresh()' to see updated value.",
+        );
+        self::assertNotEquals(
+            $originalLeft,
+            $nodeToPromote->getAttribute('lft'),
+            "Left value should have changed from original after 'makeRoot()'.",
+        );
+        self::assertNotEquals(
+            $originalRight,
+            $nodeToPromote->getAttribute('rgt'),
+            "Right value should have changed from original after 'makeRoot()'.",
+        );
+        self::assertNotEquals(
+            $originalDepth,
+            $nodeToPromote->getAttribute('depth'),
+            "Depth should have changed from original after 'makeRoot()'.",
+        );
+        self::assertNotEquals(
+            $originalTree,
+            $nodeToPromote->getAttribute('tree'),
+            "Tree should have changed from original after 'makeRoot()'.",
+        );
+
+        $grandchildAfter = MultipleTree::findOne($grandchild->id);
+
+        self::assertNotNull(
+            $grandchildAfter,
+            "'Grandchild' should still exist after parent became root.",
+        );
+        self::assertEquals(
+            $nodeToPromote->getAttribute('tree'),
+            $grandchildAfter->getAttribute('tree'),
+            "'Grandchild' should be in the same tree as the new root.",
+        );
+        self::assertEquals(
+            1,
+            $grandchildAfter->getAttribute('depth'),
+            "'Grandchild' depth should be recalculated relative to new root.",
+        );
+
+        $reloadedNode = MultipleTree::findOne($nodeToPromote->id);
+
+        self::assertNotNull(
+            $reloadedNode,
+            "Node should exist in database after 'makeRoot()'.",
+        );
+        self::assertTrue(
+            $reloadedNode->isRoot(),
+            'Reloaded node should be root.',
+        );
+        self::assertEquals(
+            1,
+            $reloadedNode->getAttribute('lft'),
+            "Reloaded node should have 'left=1'.",
+        );
+        self::assertEquals(
+            4,
+            $reloadedNode->getAttribute('rgt'),
+            "Reloaded node should have 'right=4'.",
+        );
+        self::assertEquals(
+            0,
+            $reloadedNode->getAttribute('depth'),
+            "Reloaded node should have 'depth=0'.",
+        );
+    }
 }