Make proxyDir and proxyNs nullable and optional

When using native lazy objects, it should be possible to omit these
arguments, hence the default value.
Also, when using native lazy objects, one should not have to configure
the corresponding Configuration attributes, which means
EntityManager__construct() should be able to pass null to this class,
hence the nullability.

Fixes #11997

Author: greg0ire

src/Proxy/ProxyFactory.php

@@ -132,6 +132,9 @@ public function __serialize(): array
     /** @var array<class-string, Closure> */
     private array $proxyFactories = [];
 
+    private readonly string $proxyDir;
+    private readonly string $proxyNs;
+
     /**
      * Initializes a new instance of the <tt>ProxyFactory</tt> class that is
      * connected to the given <tt>EntityManager</tt>.
@@ -143,8 +146,8 @@ public function __serialize(): array
      */
     public function __construct(
         private readonly EntityManagerInterface $em,
-        private readonly string $proxyDir,
-        private readonly string $proxyNs,
+        string|null $proxyDir = null,
+        string|null $proxyNs = null,
         bool|int $autoGenerate = self::AUTOGENERATE_NEVER,
     ) {
         if (! $proxyDir && ! $em->getConfiguration()->isNativeLazyObjectsEnabled()) {
@@ -159,6 +162,17 @@ public function __construct(
             throw ORMInvalidArgumentException::invalidAutoGenerateMode($autoGenerate);
         }
 
+        if ($proxyDir === null && $em->getConfiguration()->isNativeLazyObjectsEnabled()) {
+            $proxyDir = '';
+        }
+
+        if ($proxyNs === null && $em->getConfiguration()->isNativeLazyObjectsEnabled()) {
+            $proxyNs = '';
+        }
+
+        $this->proxyDir = $proxyDir;
+        $this->proxyNs  = $proxyNs;
+
         $this->uow                 = $em->getUnitOfWork();
         $this->autoGenerate        = (int) $autoGenerate;
         $this->identifierFlattener = new IdentifierFlattener($this->uow, $em->getMetadataFactory());

tests/Tests/ORM/Proxy/ProxyFactoryTest.php

@@ -20,6 +20,8 @@
 use Doctrine\Tests\Models\ECommerce\ECommerceFeature;
 use Doctrine\Tests\OrmTestCase;
 use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RequiresPhp;
+use ReflectionClass;
 use ReflectionProperty;
 use stdClass;
 
@@ -209,6 +211,24 @@ public function testProxyClonesParentFields(): void
         self::assertSame(1000, $cloned->getSalary(), 'Expect properties on the CompanyEmployee class to be cloned');
         self::assertSame('Bob', $cloned->getName(), 'Expect properties on the CompanyPerson class to be cloned');
     }
+
+    #[RequiresPhp('8.4')]
+    public function testProxyFactoryAcceptsNullProxyArgsWhenNativeLazyObjectsAreEnabled(): void
+    {
+        $this->emMock->getConfiguration()->enableNativeLazyObjects(true);
+        $this->proxyFactory = new ProxyFactory(
+            $this->emMock,
+            null,
+            null,
+        );
+        $proxy              = $this->proxyFactory->getProxy(
+            ECommerceFeature::class,
+            ['id' => 42],
+        );
+        $reflection         = new ReflectionClass($proxy);
+
+        self::assertTrue($reflection->isUninitializedLazyObject($proxy));
+    }
 }
 
 abstract class AbstractClass