Use default values for type-hinted arguments if type not found in container

src/AbstractFactory/ReflectionBasedAbstractFactory.php

@@ -218,7 +218,11 @@ private function resolveParameter(ReflectionParameter $parameter, ContainerInter
         $type = $parameter->getClass()->getName();
         $type = isset($this->aliases[$type]) ? $this->aliases[$type] : $type;
 
-        if (! $container->has($type)) {
+        if ($container->has($type)) {
+            return $container->get($type);
+        }
+
+        if (! $parameter->isOptional()) {
             throw new ServiceNotFoundException(sprintf(
                 'Unable to create service "%s"; unable to resolve parameter "%s" using type hint "%s"',
                 $requestedName,
@@ -227,6 +231,8 @@ private function resolveParameter(ReflectionParameter $parameter, ContainerInter
             ));
         }
 
-        return $container->get($type);
+        // Type not available in container, but the value is optional and has a
+        // default defined.
+        return $parameter->getDefaultValue();
     }
 }

test/AbstractFactory/ReflectionBasedAbstractFactoryTest.php

@@ -7,6 +7,7 @@
 
 namespace ZendTest\ServiceManager\AbstractFactory;
 
+use ArrayAccess;
 use Interop\Container\ContainerInterface;
 use PHPUnit\Framework\TestCase;
 use Zend\ServiceManager\AbstractFactory\ReflectionBasedAbstractFactory;
@@ -154,4 +155,20 @@ public function testFactoryWillUseDefaultValueWhenPresentForScalarArgument()
         $this->assertInstanceOf(TestAsset\ClassWithScalarDependencyDefiningDefaultValue::class, $instance);
         $this->assertEquals('bar', $instance->foo);
     }
+
+    /**
+     * @see https://github.com/zendframework/zend-servicemanager/issues/239
+     */
+    public function testFactoryWillUseDefaultValueForTypeHintedArgument()
+    {
+        $this->container->has('config')->willReturn(false);
+        $this->container->has(ArrayAccess::class)->willReturn(false);
+        $factory = new ReflectionBasedAbstractFactory();
+        $instance = $factory(
+            $this->container->reveal(),
+            TestAsset\ClassWithTypehintedDefaultValue::class
+        );
+        $this->assertInstanceOf(TestAsset\ClassWithTypehintedDefaultValue::class, $instance);
+        $this->assertNull($instance->value);
+    }
 }

test/AbstractFactory/TestAsset/ClassWithTypehintedDefaultValue.php

@@ -0,0 +1,20 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-2018 for the canonical source repository
+ * @copyright Copyright (c) 2018 Zend Technologies USA Inc. (https://www.zend.com)
+ * @license   https://github.com/zendframework/zend-2018/blob/master/LICENSE.md New BSD License
+ */
+
+namespace ZendTest\ServiceManager\AbstractFactory\TestAsset;
+
+use ArrayAccess;
+
+class ClassWithTypehintedDefaultValue
+{
+    public $value;
+
+    public function __construct(ArrayAccess $value = null)
+    {
+        $this->value = null;
+    }
+}