Paginator: Skip limit subquery if not required

lib/Doctrine/ORM/Tools/Pagination/Paginator.php

@@ -139,7 +139,7 @@ public function getIterator()
         $offset = $this->query->getFirstResult();
         $length = $this->query->getMaxResults();
 
-        if ($this->fetchJoinCollection) {
+        if ($this->fetchJoinCollection && $length !== null) {
             $subQuery = $this->cloneQuery($this->query);
 
             if ($this->useOutputWalker($subQuery)) {

tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1685Test.php

@@ -29,6 +29,7 @@ protected function setUp()
 
         $dql   = "SELECT ad FROM Doctrine\Tests\Models\DDC117\DDC117ArticleDetails ad";
         $query = $this->_em->createQuery($dql);
+        $query->setMaxResults(1);
 
         $this->paginator = new Paginator($query);
     }

tests/Doctrine/Tests/ORM/Functional/Ticket/GH7829Test.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\DBAL\Logging\DebugStack;
+use Doctrine\ORM\Tools\Pagination\Paginator;
+use Doctrine\Tests\Models\CMS\CmsArticle;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+/**
+ * @group GH7829
+ */
+final class GH7829Test extends OrmFunctionalTestCase
+{
+    /** @var DebugStack */
+    private $logger;
+
+    protected function setUp()
+    {
+        $this->useModelSet('cms');
+        parent::setUp();
+
+        $article = new CmsArticle();
+
+        $article->topic = 'Skip Limit Subquery';
+        $article->text  = 'Skip Limit Subquery if not required.';
+
+        $this->_em->persist($article);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $this->_em->getConnection()->getConfiguration()->setSQLLogger($this->logger = new DebugStack());
+    }
+
+    public function testPaginatorWithLimitSubquery() : void
+    {
+        $query = $this->_em->createQuery('SELECT a FROM Doctrine\Tests\Models\CMS\CmsArticle a');
+        $query->setMaxResults(1);
+
+        $paginator = new Paginator($query, true);
+        $paginator->setUseOutputWalkers(false);
+
+        $paginator->count();
+        $paginator->getIterator();
+
+        $this->assertCount(3, $this->logger->queries);
+    }
+
+    public function testPaginatorWithLimitSubquerySkipped() : void
+    {
+        $query = $this->_em->createQuery('SELECT a FROM Doctrine\Tests\Models\CMS\CmsArticle a');
+
+        $paginator = new Paginator($query, true);
+        $paginator->setUseOutputWalkers(false);
+
+        $paginator->count();
+        $paginator->getIterator();
+
+        $this->assertCount(2, $this->logger->queries);
+    }
+}

tests/Doctrine/Tests/ORM/Tools/Pagination/PaginatorTest.php

@@ -61,6 +61,7 @@ public function testExtraParametersAreStrippedWhenWalkerRemovingOriginalSelectEl
             WHERE u.id = :paramInWhere'
         );
         $query->setParameters(['paramInWhere' => $paramInWhere, 'paramInSubSelect' => $paramInSubSelect]);
+        $query->setMaxResults(1);
         $paginator = (new Paginator($query, true))->setUseOutputWalkers(false);
 
         $this->connection->expects($this->exactly(3))->method('executeQuery');
@@ -113,6 +114,7 @@ private function createPaginatorWithExtraParametersWithoutOutputWalkers(array $w
         $query = new Query($this->em);
         $query->setDQL('SELECT u FROM Doctrine\\Tests\\Models\\CMS\\CmsUser u');
         $query->setParameters(['paramInWhere' => 1]);
+        $query->setMaxResults(1);
 
         return (new Paginator($query, true))->setUseOutputWalkers(false);
     }