Solve issue 293 about IDENTITY

src/Type/Doctrine/Query/QueryResultTypeWalker.php

@@ -550,6 +550,7 @@ public function walkFunction($function)
 				}
 
 				$nullable = ($joinColumn['nullable'] ?? true)
+					|| $this->isQueryComponentNullable($dqlAlias)
 					|| $this->hasAggregateWithoutGroupBy();
 
 				$fieldType = $this->resolveDatabaseInternalType($typeName, $enumType, $nullable);

tests/Type/Doctrine/Query/QueryResultTypeWalkerTest.php

@@ -1377,6 +1377,7 @@ public function getTestData(): iterable
 				[new ConstantIntegerType(6), TypeCombinator::addNull($this->numericStringOrInt())],
 				[new ConstantIntegerType(7), TypeCombinator::addNull(new MixedType())],
 				[new ConstantIntegerType(8), TypeCombinator::addNull($this->numericStringOrInt())],
+				[new ConstantIntegerType(9), TypeCombinator::addNull($this->numericStringOrInt())],
 			]),
 			'
 				SELECT		IDENTITY(m.oneNull),
@@ -1386,8 +1387,10 @@ public function getTestData(): iterable
 							IDENTITY(m.compoundPk, \'id\'),
 							IDENTITY(m.compoundPk, \'version\'),
 							IDENTITY(m.compoundPkAssoc),
-							IDENTITY(m.compoundPkAssoc, \'version\')
+							IDENTITY(m.compoundPkAssoc, \'version\'),
+							IDENTITY(o.subOne)
 				FROM		QueryResult\Entities\Many m
+				LEFT JOIN   m.oneNull o
 			',
 		];
 

tests/Type/Doctrine/data/QueryResult/Entities/One.php

@@ -8,8 +8,8 @@
 use Doctrine\ORM\Mapping\Entity;
 use Doctrine\ORM\Mapping\Id;
 use Doctrine\ORM\Mapping\JoinColumn;
-use Doctrine\ORM\Mapping\ManyToOne;
 use Doctrine\ORM\Mapping\OneToMany;
+use Doctrine\ORM\Mapping\OneToOne;
 
 /**
  * @Entity
@@ -45,6 +45,14 @@ class One
 	 */
 	public $stringNullColumn;
 
+	/**
+	 * @OneToOne(targetEntity="QueryResult\Entities\SubOne", cascade={"persist"})
+	 * @JoinColumn(nullable=false)
+	 *
+	 * @var SubOne
+	 */
+	public $subOne;
+
 	/**
 	 * @OneToMany(targetEntity="QueryResult\Entities\Many", mappedBy="one")
 	 *
@@ -58,4 +66,9 @@ class One
 	 * @var Embedded
 	 */
 	public $embedded;
+
+	public function __construct()
+	{
+		$this->subOne = new SubOne();
+	}
 }

tests/Type/Doctrine/data/QueryResult/Entities/SubOne.php

@@ -0,0 +1,23 @@
+<?php declare(strict_types=1);
+
+namespace QueryResult\Entities;
+
+use Doctrine\ORM\Mapping\Column;
+use Doctrine\ORM\Mapping\Entity;
+use Doctrine\ORM\Mapping\Id;
+use Doctrine\ORM\Mapping\GeneratedValue;
+
+/**
+ * @Entity
+ */
+class SubOne
+{
+	/**
+	 * @GeneratedValue()
+	 * @Column(type="integer")
+	 * @Id
+	 *
+	 * @var string
+	 */
+	public $id;
+}