Added the SessionValueResolver

src/Symfony/Bundle/FrameworkBundle/Resources/config/web.xml

@@ -32,6 +32,10 @@
             <tag name="controller.argument_value_resolver" priority="50" />
         </service>
 
+        <service id="argument_resolver.session" class="Symfony\Component\HttpKernel\Controller\ArgumentResolver\SessionValueResolver" public="false">
+            <tag name="controller.argument_value_resolver" priority="50" />
+        </service>
+
         <service id="argument_resolver.default" class="Symfony\Component\HttpKernel\Controller\ArgumentResolver\DefaultValueResolver" public="false">
             <tag name="controller.argument_value_resolver" priority="-100" />
         </service>

src/Symfony/Component/HttpKernel/Controller/ArgumentResolver.php

@@ -15,6 +15,7 @@ use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Controller\ArgumentResolver\DefaultValueResolver;
 use Symfony\Component\HttpKernel\Controller\ArgumentResolver\RequestAttributeValueResolver;
 use Symfony\Component\HttpKernel\Controller\ArgumentResolver\RequestValueResolver;
+use Symfony\Component\HttpKernel\Controller\ArgumentResolver\SessionValueResolver;
 use Symfony\Component\HttpKernel\Controller\ArgumentResolver\VariadicValueResolver;
 use Symfony\Component\HttpKernel\ControllerMetadata\ArgumentMetadataFactory;
 use Symfony\Component\HttpKernel\ControllerMetadata\ArgumentMetadataFactoryInterface;
@@ -85,6 +86,7 @@ final class ArgumentResolver implements ArgumentResolverInterface
         return array(
             new RequestAttributeValueResolver(),
             new RequestValueResolver(),
+            new SessionValueResolver(),
             new DefaultValueResolver(),
             new VariadicValueResolver(),
         );

src/Symfony/Component/HttpKernel/Controller/ArgumentResolver/SessionValueResolver.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\Controller\ArgumentResolver;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Session\SessionInterface;
+use Symfony\Component\HttpKernel\Controller\ArgumentValueResolverInterface;
+use Symfony\Component\HttpKernel\ControllerMetadata\ArgumentMetadata;
+
+/**
+ * Yields the Session.
+ *
+ * @author Iltar van der Berg <kjarli@gmail.com>
+ */
+final class SessionValueResolver implements ArgumentValueResolverInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function supports(Request $request, ArgumentMetadata $argument)
+    {
+        if (SessionInterface::class !== $argument->getType() && !is_subclass_of($argument->getType(), SessionInterface::class)) {
+            return false;
+        }
+
+        $session = $request->getSession();
+
+        if (null === $session) {
+            return false;
+        }
+
+        $class = get_class($session);
+
+        return $class === $argument->getType() || is_subclass_of($class, $argument->getType());
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function resolve(Request $request, ArgumentMetadata $argument)
+    {
+        yield $request->getSession();
+    }
+}

src/Symfony/Component/HttpKernel/Tests/Controller/ArgumentResolverTest.php

@@ -12,14 +12,15 @@
 namespace Symfony\Component\HttpKernel\Tests\Controller;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Session\Session;
+use Symfony\Component\HttpFoundation\Session\SessionInterface;
+use Symfony\Component\HttpFoundation\Session\Storage\MockArraySessionStorage;
 use Symfony\Component\HttpKernel\Controller\ArgumentResolver;
-use Symfony\Component\HttpKernel\Controller\ArgumentResolver\DefaultValueResolver;
 use Symfony\Component\HttpKernel\Controller\ArgumentResolver\RequestAttributeValueResolver;
-use Symfony\Component\HttpKernel\Controller\ArgumentResolver\RequestValueResolver;
-use Symfony\Component\HttpKernel\Controller\ArgumentResolver\VariadicValueResolver;
 use Symfony\Component\HttpKernel\Controller\ArgumentValueResolverInterface;
 use Symfony\Component\HttpKernel\ControllerMetadata\ArgumentMetadataFactory;
 use Symfony\Component\HttpKernel\Tests\Fixtures\Controller\ExtendingRequest;
+use Symfony\Component\HttpKernel\Tests\Fixtures\Controller\ExtendingSession;
 use Symfony\Component\HttpKernel\Tests\Fixtures\Controller\NullableController;
 use Symfony\Component\HttpKernel\Tests\Fixtures\Controller\VariadicController;
 use Symfony\Component\HttpFoundation\Request;
@@ -32,14 +33,8 @@ class ArgumentResolverTest extends TestCase
     public static function setUpBeforeClass()
     {
         $factory = new ArgumentMetadataFactory();
-        $argumentValueResolvers = array(
-            new RequestAttributeValueResolver(),
-            new RequestValueResolver(),
-            new DefaultValueResolver(),
-            new VariadicValueResolver(),
-        );
 
-        self::$resolver = new ArgumentResolver($factory, $argumentValueResolvers);
+        self::$resolver = new ArgumentResolver($factory);
     }
 
     public function testDefaultState()
@@ -241,6 +236,73 @@ class ArgumentResolverTest extends TestCase
         $this->assertEquals(array(null, null, 'value', 'mandatory'), self::$resolver->getArguments($request, $controller));
     }
 
+    public function testGetSessionArguments()
+    {
+        $session = new Session(new MockArraySessionStorage());
+        $request = Request::create('/');
+        $request->setSession($session);
+        $controller = array($this, 'controllerWithSession');
+
+        $this->assertEquals(array($session), self::$resolver->getArguments($request, $controller));
+    }
+
+    public function testGetSessionArgumentsWithExtendedSession()
+    {
+        $session = new ExtendingSession(new MockArraySessionStorage());
+        $request = Request::create('/');
+        $request->setSession($session);
+        $controller = array($this, 'controllerWithExtendingSession');
+
+        $this->assertEquals(array($session), self::$resolver->getArguments($request, $controller));
+    }
+
+    public function testGetSessionArgumentsWithInterface()
+    {
+        $session = $this->getMockBuilder(SessionInterface::class)->getMock();
+        $request = Request::create('/');
+        $request->setSession($session);
+        $controller = array($this, 'controllerWithSessionInterface');
+
+        $this->assertEquals(array($session), self::$resolver->getArguments($request, $controller));
+    }
+
+    /**
+     * @expectedException \RuntimeException
+     */
+    public function testGetSessionMissMatchWithInterface()
+    {
+        $session = $this->getMockBuilder(SessionInterface::class)->getMock();
+        $request = Request::create('/');
+        $request->setSession($session);
+        $controller = array($this, 'controllerWithExtendingSession');
+
+        self::$resolver->getArguments($request, $controller);
+    }
+
+    /**
+     * @expectedException \RuntimeException
+     */
+    public function testGetSessionMissMatchWithImplementation()
+    {
+        $session = new Session(new MockArraySessionStorage());
+        $request = Request::create('/');
+        $request->setSession($session);
+        $controller = array($this, 'controllerWithExtendingSession');
+
+        self::$resolver->getArguments($request, $controller);
+    }
+
+    /**
+     * @expectedException \RuntimeException
+     */
+    public function testGetSessionMissMatchOnNull()
+    {
+        $request = Request::create('/');
+        $controller = array($this, 'controllerWithExtendingSession');
+
+        self::$resolver->getArguments($request, $controller);
+    }
+
     public function __invoke($foo, $bar = null)
     {
     }
@@ -268,6 +330,18 @@ class ArgumentResolverTest extends TestCase
     protected function controllerWithExtendingRequest(ExtendingRequest $request)
     {
     }
+
+    protected function controllerWithSession(Session $session)
+    {
+    }
+
+    protected function controllerWithSessionInterface(SessionInterface $session)
+    {
+    }
+
+    protected function controllerWithExtendingSession(ExtendingSession $session)
+    {
+    }
 }
 
 function controller_function($foo, $foobar)

src/Symfony/Component/HttpKernel/Tests/Fixtures/Controller/ExtendingSession.php

@@ -0,0 +1,18 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\Tests\Fixtures\Controller;
+
+use Symfony\Component\HttpFoundation\Session\Session;
+
+class ExtendingSession extends Session
+{
+}