Add a functional test covering #8127

tests/Doctrine/Tests/ORM/Functional/Ticket/GH8127Test.php

@@ -0,0 +1,102 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\ORM\Mapping as ORM;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+class GH8127Test extends OrmFunctionalTestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->createSchemaForModels(
+            GH8127Root::class,
+            GH8127Middle::class,
+            GH8127Leaf::class
+        );
+    }
+
+    /**
+     * @dataProvider queryClasses
+     */
+    public function testLoadFieldsFromAllClassesInHierarchy(string $queryClass): void
+    {
+        $entity         = new GH8127Leaf();
+        $entity->root   = 'root';
+        $entity->middle = 'middle';
+        $entity->leaf   = 'leaf';
+
+        $this->_em->persist($entity);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $loadedEntity = $this->_em->find(GH8127Root::class, $entity->id);
+
+        self::assertSame('root', $loadedEntity->root);
+        self::assertSame('middle', $loadedEntity->middle);
+        self::assertSame('leaf', $loadedEntity->leaf);
+    }
+
+    public function queryClasses(): array
+    {
+        return [
+            'query via root entity' => [GH8127Root::class],
+            'query via leaf entity' => [GH8127Leaf::class],
+        ];
+    }
+}
+
+/**
+ * @ORM\Entity
+ * @ORM\Table(name="root")
+ * @ORM\InheritanceType("JOINED")
+ * @ORM\DiscriminatorMap({ "root": "GH8127Root", "middle": "GH8127Middle", "leaf": "GH8127Leaf"})
+ */
+abstract class GH8127Root
+{
+    /**
+     * @ORM\Id
+     * @ORM\GeneratedValue(strategy="AUTO")
+     * @ORM\Column(type="integer")
+     *
+     * @var int
+     */
+    public $id;
+
+    /**
+     * @ORM\Column
+     *
+     * @var string
+     */
+    public $root;
+}
+
+/**
+ * @ORM\Entity
+ */
+abstract class GH8127Middle extends GH8127Root
+{
+    /**
+     * @ORM\Column
+     *
+     * @var string
+     */
+    public $middle;
+}
+
+/**
+ * @ORM\Entity
+ */
+class GH8127Leaf extends GH8127Middle
+{
+    /**
+     * @ORM\Column
+     *
+     * @var string
+     */
+    public $leaf;
+}