[doctrineGH-8413] Bugfix: Iterating with multiple, mixed results

When multiple entity results are part of a row, the result handling
must be different. In addition mixed results with scalars are broken
and now throw an exception as illegal operation.

lib/Doctrine/ORM/AbstractQuery.php

@@ -31,6 +31,7 @@
 use Doctrine\ORM\Internal\Hydration\IterableResult;
 use Doctrine\ORM\Mapping\MappingException as ORMMappingException;
 use Doctrine\ORM\Query\Parameter;
+use Doctrine\ORM\Query\QueryException;
 use Doctrine\ORM\Query\ResultSetMapping;
 use Doctrine\Persistence\Mapping\MappingException;
 use Traversable;
@@ -999,6 +1000,11 @@ public function toIterable(iterable $parameters = [], $hydrationMode = null): it
         }
 
         $rsm  = $this->getResultSetMapping();
+
+        if ($rsm->isMixed && count($rsm->scalarMappings) > 0) {
+            throw QueryException::iterateWithMixedResultNotAllowed();
+        }
+
         $stmt = $this->_doExecute();
 
         return $this->_em->newHydrator($this->_hydrationMode)->toIterable($stmt, $rsm, $this->_hints);

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

@@ -180,7 +180,11 @@ public function toIterable(Statement $stmt, ResultSetMapping $resultSetMapping,
 
             $this->cleanupAfterRowIteration();
 
-            yield end($result);
+            if (count($result) === 1) {
+                yield end($result);
+            } else {
+                yield $result;
+            }
         }
     }
 

lib/Doctrine/ORM/Query/QueryException.php

@@ -227,6 +227,11 @@ public static function iterateWithFetchJoinNotAllowed($assoc)
         );
     }
 
+    public static function iterateWithMixedResultNotAllowed(): QueryException
+    {
+        return new self('Iterating a query with mixed results (using scalars) is not supported.');
+    }
+
     /**
      * @return QueryException
      */

tests/Doctrine/Tests/ORM/Functional/AdvancedDqlQueryTest.php

@@ -171,8 +171,6 @@ public function testSelectSubselect(): void
         $this->assertEquals('Caramba', $result[0]['brandName']);
 
         $this->_em->clear();
-
-        IterableTester::assertResultsAreTheSame($query);
     }
 
     public function testInSubselect(): void

tests/Doctrine/Tests/ORM/Functional/QueryTest.php

@@ -301,6 +301,51 @@ public function testIterateResult_IterativelyBuildUpUnitOfWork(): void
         self::assertSame(2, $iteratedCount);
     }
 
+    public function testToIterableWithMultipleSelectElements(): void
+    {
+        $author = new CmsUser();
+        $author->name = 'Ben';
+        $author->username = 'beberlei';
+
+        $article1 = new CmsArticle();
+        $article1->topic = 'Doctrine 2';
+        $article1->text = 'This is an introduction to Doctrine 2.';
+        $article1->setAuthor($author);
+
+        $article2 = new CmsArticle();
+        $article2->topic = 'Symfony 2';
+        $article2->text = 'This is an introduction to Symfony 2.';
+        $article2->setAuthor($author);
+
+        $this->_em->persist($article1);
+        $this->_em->persist($article2);
+        $this->_em->persist($author);
+
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $query = $this->_em->createQuery('select a, u from ' . CmsArticle::class . ' a JOIN ' . CmsUser::class . ' u WITH a.user = u');
+
+        $result = iterator_to_array($query->toIterable());
+
+        $this->assertCount(2, $result);
+
+        foreach ($result as $row) {
+            $this->assertCount(2, $row);
+            $this->assertInstanceOf(CmsArticle::class, $row[0]);
+            $this->assertInstanceOf(CmsUser::class, $row[1]);
+        }
+    }
+
+    public function testToIterableWithMixedResultIsNotAllowed(): void
+    {
+        $this->expectException(QueryException::class);
+        $this->expectExceptionMessage('Iterating a query with mixed results (using scalars) is not supported.');
+
+        $query = $this->_em->createQuery('select a, a.topic from ' . CmsArticle::class . ' a');
+        $query->toIterable();
+    }
+
     public function testIterateResultClearEveryCycle(): void
     {
         $article1        = new CmsArticle();