[Tree] Fix TreeObjectHydrator compatibility with ORM 3

CHANGELOG.md

@@ -21,6 +21,9 @@ a release.
 ### Changed
 - All: Removed the dollar sign from the generated cache ID for extension metadata to ensure only characters mandated by [PSR-6](https://www.php-fig.org/psr/psr-6/#definitions) are used, improving compatibility with caching implementations with strict character requirements (#2978)
 
+### Fixed
+- Tree: Fix TreeObjectHydrator compatibility with ORM 3 when parent property is defined before children property in entity
+
 ## [3.22.0] - 2025-12-13
 ### Added
 - Support for Symfony 8

src/Tree/Hydrator/ORM/TreeObjectHydrator.php

@@ -250,6 +250,13 @@ protected function getChildrenField($entityClass)
 
             $associationMapping = $meta->getAssociationMapping($property->getName());
 
+            // ORM 3 mapping objects implement ArrayAccess, so both ORM 2 arrays
+            // and ORM 3 objects go through the same path. Owning-side mappings (the parent
+            // ManyToOne) have no `mappedBy`, hence the isset() guard.
+            if (!isset($associationMapping['mappedBy'])) {
+                continue;
+            }
+
             // Make sure the association is mapped by the parent property
             if ($associationMapping['mappedBy'] !== $this->parentField) {
                 continue;

tests/Gedmo/Tree/Fixture/RootCategoryReversed.php

@@ -0,0 +1,191 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the Doctrine Behavioral Extensions package.
+ * (c) Gediminas Morkevicius <gediminas.morkevicius@gmail.com> http://www.gediminasm.org
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Gedmo\Tests\Tree\Fixture;
+
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Common\Collections\Collection;
+use Doctrine\DBAL\Types\Types;
+use Doctrine\ORM\Mapping as ORM;
+use Gedmo\Mapping\Annotation as Gedmo;
+use Gedmo\Tree\Entity\Repository\NestedTreeRepository;
+use Gedmo\Tree\Node;
+
+/**
+ * @ORM\Entity(repositoryClass="Gedmo\Tree\Entity\Repository\NestedTreeRepository")
+ *
+ * @Gedmo\Tree(type="nested")
+ */
+#[ORM\Entity(repositoryClass: NestedTreeRepository::class)]
+#[Gedmo\Tree(type: 'nested')]
+class RootCategoryReversed implements Node
+{
+    /**
+     * @Gedmo\TreeParent
+     *
+     * @ORM\ManyToOne(targetEntity="RootCategoryReversed", inversedBy="children")
+     * @ORM\JoinColumns({
+     *     @ORM\JoinColumn(name="parent_id", referencedColumnName="id", onDelete="CASCADE")
+     * })
+     */
+    #[ORM\ManyToOne(targetEntity: self::class, inversedBy: 'children')]
+    #[ORM\JoinColumn(name: 'parent_id', referencedColumnName: 'id', onDelete: 'CASCADE')]
+    #[Gedmo\TreeParent]
+    private ?RootCategoryReversed $parent = null;
+
+    /**
+     * @var Collection<int, self>
+     *
+     * @ORM\OneToMany(targetEntity="RootCategoryReversed", mappedBy="parent")
+     */
+    #[ORM\OneToMany(targetEntity: self::class, mappedBy: 'parent')]
+    private $children;
+
+    /**
+     * @var int|null
+     *
+     * @ORM\Id
+     * @ORM\GeneratedValue
+     * @ORM\Column(type="integer")
+     */
+    #[ORM\Id]
+    #[ORM\GeneratedValue]
+    #[ORM\Column(type: Types::INTEGER)]
+    private $id;
+
+    /**
+     * @ORM\Column(name="title", type="string", length=64)
+     */
+    #[ORM\Column(name: 'title', type: Types::STRING, length: 64)]
+    private ?string $title = null;
+
+    /**
+     * @var int|null
+     *
+     * @Gedmo\TreeLeft
+     *
+     * @ORM\Column(name="lft", type="integer")
+     */
+    #[ORM\Column(name: 'lft', type: Types::INTEGER)]
+    #[Gedmo\TreeLeft]
+    private $lft;
+
+    /**
+     * @var int|null
+     *
+     * @Gedmo\TreeRight
+     *
+     * @ORM\Column(name="rgt", type="integer")
+     */
+    #[ORM\Column(name: 'rgt', type: Types::INTEGER)]
+    #[Gedmo\TreeRight]
+    private $rgt;
+
+    /**
+     * @var int|null
+     *
+     * @Gedmo\TreeRoot
+     *
+     * @ORM\Column(type="integer")
+     */
+    #[ORM\Column(type: Types::INTEGER)]
+    #[Gedmo\TreeRoot]
+    private $root;
+
+    /**
+     * @var int|null
+     *
+     * @Gedmo\TreeLevel(base=1)
+     *
+     * @ORM\Column(name="lvl", type="integer")
+     */
+    #[ORM\Column(name: 'lvl', type: Types::INTEGER)]
+    #[Gedmo\TreeLevel(base: 1)]
+    private $level;
+
+    private ?Node $sibling = null;
+
+    public function __construct()
+    {
+        $this->children = new ArrayCollection();
+    }
+
+    public function getId(): ?int
+    {
+        return $this->id;
+    }
+
+    public function setTitle(?string $title): void
+    {
+        $this->title = $title;
+    }
+
+    public function getTitle(): ?string
+    {
+        return $this->title;
+    }
+
+    public function setParent(?self $parent = null): void
+    {
+        $this->parent = $parent;
+    }
+
+    public function getParent(): ?self
+    {
+        return $this->parent;
+    }
+
+    public function getRoot(): ?int
+    {
+        return $this->root;
+    }
+
+    public function getLeft(): ?int
+    {
+        return $this->lft;
+    }
+
+    public function getRight(): ?int
+    {
+        return $this->rgt;
+    }
+
+    public function getLevel(): ?int
+    {
+        return $this->level;
+    }
+
+    /**
+     * @return Collection<int, self>
+     */
+    public function getChildren(): Collection
+    {
+        return $this->children;
+    }
+
+    /**
+     * @param Collection<int, self> $children
+     */
+    public function setChildren(Collection $children): void
+    {
+        $this->children = $children;
+    }
+
+    public function setSibling(Node $node): void
+    {
+        $this->sibling = $node;
+    }
+
+    public function getSibling(): ?Node
+    {
+        return $this->sibling;
+    }
+}

tests/Gedmo/Tree/TreeObjectHydratorTest.php

@@ -16,6 +16,7 @@
 use Gedmo\Tests\Tool\BaseTestCaseORM;
 use Gedmo\Tests\Tree\Fixture\Category;
 use Gedmo\Tests\Tree\Fixture\RootCategory;
+use Gedmo\Tests\Tree\Fixture\RootCategoryReversed;
 use Gedmo\Tree\Entity\Repository\NestedTreeRepository;
 use Gedmo\Tree\Hydrator\ORM\TreeObjectHydrator;
 use Gedmo\Tree\TreeListener;
@@ -166,11 +167,52 @@ public function testMultipleRootNodesTreeHydration(): void
         static::assertCount(2, $this->queryLogger->queries);
     }
 
+    public function testFullTreeHydrationWithReversedFieldOrder(): void
+    {
+        $this->populateReversed();
+        $this->em->clear();
+
+        $this->queryLogger->reset();
+
+        $repo = $this->em->getRepository(RootCategoryReversed::class);
+
+        $result = $repo->createQueryBuilder('node')
+            ->orderBy('node.lft', 'ASC')
+            ->getQuery()
+            ->setHint(Query::HINT_INCLUDE_META_COLUMNS, true)
+            ->getResult('tree');
+
+        static::assertCount(1, $result);
+
+        $food = $result[0];
+        static::assertSame('Food', $food->getTitle());
+        static::assertCount(2, $food->getChildren());
+
+        $fruits = $food->getChildren()->get(0);
+        static::assertSame('Fruits', $fruits->getTitle());
+        static::assertCount(2, $fruits->getChildren());
+
+        $vegetables = $food->getChildren()->get(1);
+        static::assertSame('Vegetables', $vegetables->getTitle());
+        static::assertCount(0, $vegetables->getChildren());
+
+        $oranges = $fruits->getChildren()->get(0);
+        static::assertSame('Oranges', $oranges->getTitle());
+        static::assertCount(0, $oranges->getChildren());
+
+        $citrons = $fruits->getChildren()->get(1);
+        static::assertSame('Citrons', $citrons->getTitle());
+        static::assertCount(0, $citrons->getChildren());
+
+        static::assertCount(1, $this->queryLogger->queries);
+    }
+
     protected function getUsedEntityFixtures(): array
     {
         return [
             Category::class,
             RootCategory::class,
+            RootCategoryReversed::class,
         ];
     }
 
@@ -210,4 +252,33 @@ private function populate(): void
 
         $this->em->flush();
     }
+
+    private function populateReversed(): void
+    {
+        $repo = $this->em->getRepository(RootCategoryReversed::class);
+
+        $food = new RootCategoryReversed();
+        $food->setTitle('Food');
+
+        $fruits = new RootCategoryReversed();
+        $fruits->setTitle('Fruits');
+
+        $vegetables = new RootCategoryReversed();
+        $vegetables->setTitle('Vegetables');
+
+        $oranges = new RootCategoryReversed();
+        $oranges->setTitle('Oranges');
+
+        $citrons = new RootCategoryReversed();
+        $citrons->setTitle('Citrons');
+
+        $repo
+            ->persistAsFirstChild($food)
+            ->persistAsLastChildOf($fruits, $food)
+            ->persistAsLastChildOf($vegetables, $food)
+            ->persistAsLastChildOf($oranges, $fruits)
+            ->persistAsLastChildOf($citrons, $fruits);
+
+        $this->em->flush();
+    }
 }