Fix inheritance join alias

lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php

@@ -358,8 +358,8 @@ protected function hydrateRowData(array $row, array &$result)
 
                 // Get a reference to the parent object to which the joined element belongs.
                 if ($this->_rsm->isMixed && isset($this->rootAliases[$parentAlias])) {
-                    $first = reset($this->resultPointers);
-                    $parentObject = $first[key($first)];
+                    $objectClass = $this->resultPointers[$parentAlias];
+                    $parentObject = $objectClass[key($objectClass)];
                 } else if (isset($this->resultPointers[$parentAlias])) {
                     $parentObject = $this->resultPointers[$parentAlias];
                 } else {

tests/Doctrine/Tests/ORM/Functional/Ticket/GH6362Test.php

@@ -0,0 +1,144 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\Tests\OrmFunctionalTestCase;
+use Doctrine\ORM\Query;
+use Doctrine\ORM\Query\ResultSetMapping;
+use Doctrine\Tests\Mocks\HydratorMockStatement;
+
+final class GH6362Test extends OrmFunctionalTestCase
+{
+    protected function setUp()
+    {
+        parent::setUp();
+
+        $this->_schemaTool->createSchema(
+            [
+                $this->_em->getClassMetadata(GH6362Start::class),
+                $this->_em->getClassMetadata(GH6362Base::class),
+                $this->_em->getClassMetadata(GH6362Child::class),
+                $this->_em->getClassMetadata(GH6362Join::class),
+            ]
+        );
+    }
+
+    /**
+     * @group 6362
+     *
+     * SELECT a as base, b, c, d
+     * FROM Start a
+     * LEFT JOIN a.bases b
+     * LEFT JOIN Child c WITH b.id = c.id
+     * LEFT JOIN c.joins d
+     */
+    public function testInheritanceJoinAlias()
+    {
+        $rsm = new ResultSetMapping;
+        $rsm->addEntityResult(GH6362Start::class, 'a', 'base');
+        $rsm->addJoinedEntityResult(GH6362Base::class, 'b', 'a', 'bases');
+        $rsm->addEntityResult(GH6362Child::class, 'c');
+        $rsm->addJoinedEntityResult(GH6362Join::class, 'd', 'c', 'joins');
+
+        $rsm->addFieldResult('a', 'id_0', 'id');
+        $rsm->addFieldResult('b', 'id_1', 'id');
+        $rsm->addFieldResult('c', 'id_2', 'id');
+        $rsm->addFieldResult('d', 'id_3', 'id');
+
+        $rsm->addMetaResult('a', 'bases_id_4', 'bases_id', false, 'integer');
+        $rsm->addMetaResult('b', 'type_5', 'type');
+        $rsm->addMetaResult('c', 'type_6', 'type');
+        $rsm->addMetaResult('d', 'child_id_7', 'child_id', false, 'integer');
+
+        $rsm->setDiscriminatorColumn('b', 'type_5');
+        $rsm->setDiscriminatorColumn('c', 'type_6');
+
+        $resultSet = [
+            [
+                'id_0' => '1',
+                'id_1' => '1',
+                'id_2' => '1',
+                'id_3' => '1',
+                'bases_id_4' => '1',
+                'type_5' => 'child',
+                'type_6' => 'child',
+                'child_id_7' => '1',
+            ],
+        ];
+
+        $stmt     = new HydratorMockStatement($resultSet);
+        $hydrator = new \Doctrine\ORM\Internal\Hydration\ObjectHydrator($this->_em);
+        $result   = $hydrator->hydrateAll($stmt, $rsm, [Query::HINT_FORCE_PARTIAL_LOAD => true]);
+
+        $this->assertInstanceOf(GH6362Start::class, $result[0]['base']);
+        $this->assertInstanceOf(GH6362Child::class, $result[1][0]);
+    }
+}
+
+/**
+ * @Entity
+ */
+class GH6362Start
+{
+    /**
+     * @Column(type="integer")
+     * @Id
+     * @GeneratedValue
+     */
+    protected $id;
+
+    /**
+     * @ManyToOne(targetEntity="GH6362Base", inversedBy="starts")
+     */
+    private $bases;
+}
+
+/**
+ * @InheritanceType("SINGLE_TABLE")
+ * @DiscriminatorColumn(name="type", type="string")
+ * @DiscriminatorMap({"child" = "GH6362Child"})
+ * @Entity
+ */
+abstract class GH6362Base
+{
+    /**
+     * @Column(type="integer")
+     * @Id
+     * @GeneratedValue
+     */
+    protected $id;
+
+    /**
+     * @OneToMany(targetEntity="GH6362Start", mappedBy="bases")
+     */
+    private $starts;
+}
+
+/**
+ * @Entity
+ */
+class GH6362Child extends GH6362Base
+{
+    /**
+     * @OneToMany(targetEntity="GH6362Join", mappedBy="child")
+     */
+    private $joins;
+}
+
+/**
+ * @Entity
+ */
+class GH6362Join
+{
+    /**
+     * @Column(type="integer")
+     * @Id
+     * @GeneratedValue
+     */
+    private $id;
+
+    /**
+     * @ManyToOne(targetEntity="GH6362Child", inversedBy="joins")
+     */
+    private $child;
+}