(Try to) add a reproducer for doctrine#10889

tests/Doctrine/Tests/ORM/Functional/Ticket/GH10889Test.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\Tests\Models\CMS\CmsAddress;
+use Doctrine\Tests\Models\CMS\CmsUser;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+class GH10889Test extends OrmFunctionalTestCase
+{
+    protected function setUp(): void
+    {
+        $this->useModelSet('cms');
+
+        parent::setUp();
+    }
+
+    public function testDuplicateDqlAliasinSelectClauseShouldNotFail(): void
+    {
+        $address          = new CmsAddress();
+        $address->city    = 'bonn';
+        $address->country = 'Germany';
+        $address->street  = 'somestreet!';
+        $address->zip     = 12345;
+
+        $user           = new CmsUser();
+        $user->username = 'joedoe';
+        $user->name     = 'joe';
+        $user->setAddress($address);
+
+        $this->_em->persist($address);
+        $this->_em->persist($user);
+        $this->_em->flush();
+
+        $qb    = $this->_em->createQueryBuilder();
+        $query = $qb->select(['u', 'a'])
+            ->from(CmsUser::class, 'u')
+            ->join('u.address', 'a')
+            ->addSelect('a')
+            ->getQuery();
+
+        self::assertCount(1, $query->getResult());
+    }
+}