feature #24155 [FrameworkBundle][HttpKernel] Add DI tag for resettabl…

…e services (derrabus)

This PR was merged into the 3.4 branch.

Discussion
----------

[FrameworkBundle][HttpKernel] Add DI tag for resettable services

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #23984
| License       | MIT
| Doc PR        | TODO

This PR uses #24033 to introduce a DI tag for resettable services.

TODO after merge:
* Add an interface, make the "method" attribute optional and enable autoconfiguration.
* Consider adding a config option to enable/disable this feature.
* Configure leaking services of the core bundles as resettable.

Commits
-------

d9a6b76 A DI tag for resettable services.

src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php

@@ -33,6 +33,7 @@
 use Symfony\Component\HttpKernel\DependencyInjection\ControllerArgumentValueResolverPass;
 use Symfony\Component\HttpKernel\DependencyInjection\RegisterControllerArgumentLocatorsPass;
 use Symfony\Component\HttpKernel\DependencyInjection\RemoveEmptyControllerArgumentLocatorsPass;
+use Symfony\Component\HttpKernel\DependencyInjection\ResettableServicePass;
 use Symfony\Component\PropertyInfo\DependencyInjection\PropertyInfoPass;
 use Symfony\Component\Routing\DependencyInjection\RoutingResolverPass;
 use Symfony\Component\Serializer\DependencyInjection\SerializerPass;
@@ -117,6 +118,7 @@ public function build(ContainerBuilder $container)
         $container->addCompilerPass(new CachePoolPrunerPass(), PassConfig::TYPE_AFTER_REMOVING);
         $this->addCompilerPassIfExists($container, FormPass::class);
         $container->addCompilerPass(new WorkflowGuardListenerPass());
+        $container->addCompilerPass(new ResettableServicePass());
 
         if ($container->getParameter('kernel.debug')) {
             $container->addCompilerPass(new AddDebugLogProcessorPass(), PassConfig::TYPE_BEFORE_OPTIMIZATION, -32);

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

@@ -74,5 +74,11 @@
         <service id="Symfony\Component\Config\Resource\SelfCheckingResourceChecker">
             <tag name="config_cache.resource_checker" priority="-990" />
         </service>
+
+        <service id="Symfony\Component\HttpKernel\EventListener\ServiceResetListener">
+            <argument /> <!-- ResettableServicePass will inject an iterator of initialized services here ($serviceId => $serviceInstance) -->
+            <argument type="collection" /> <!-- ResettableServicePass will inject an array of reset methods here ($serviceId => $method) -->
+            <tag name="kernel.event_subscriber" />
+        </service>
     </services>
 </container>

src/Symfony/Component/HttpKernel/DependencyInjection/ResettableServicePass.php

@@ -0,0 +1,69 @@
+<?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\DependencyInjection;
+
+use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\DependencyInjection\Exception\RuntimeException;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\HttpKernel\EventListener\ServiceResetListener;
+
+/**
+ * @author Alexander M. Turek <me@derrabus.de>
+ */
+class ResettableServicePass implements CompilerPassInterface
+{
+    private $tagName;
+
+    /**
+     * @param string $tagName
+     */
+    public function __construct($tagName = 'kernel.reset')
+    {
+        $this->tagName = $tagName;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function process(ContainerBuilder $container)
+    {
+        if (!$container->has(ServiceResetListener::class)) {
+            return;
+        }
+
+        $services = $methods = array();
+
+        foreach ($container->findTaggedServiceIds($this->tagName, true) as $id => $tags) {
+            $services[$id] = new Reference($id, ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE);
+            $attributes = $tags[0];
+
+            if (!isset($attributes['method'])) {
+                throw new RuntimeException(sprintf('Tag %s requires the "method" attribute to be set.', $this->tagName));
+            }
+
+            $methods[$id] = $attributes['method'];
+        }
+
+        if (empty($services)) {
+            $container->removeDefinition(ServiceResetListener::class);
+
+            return;
+        }
+
+        $container->findDefinition(ServiceResetListener::class)
+            ->replaceArgument(0, new IteratorArgument($services))
+            ->replaceArgument(1, $methods);
+    }
+}

src/Symfony/Component/HttpKernel/EventListener/ServiceResetListener.php

@@ -0,0 +1,50 @@
+<?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\EventListener;
+
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+/**
+ * Clean up services between requests.
+ *
+ * @author Alexander M. Turek <me@derrabus.de>
+ */
+class ServiceResetListener implements EventSubscriberInterface
+{
+    private $services;
+    private $resetMethods;
+
+    public function __construct(\Traversable $services, array $resetMethods)
+    {
+        $this->services = $services;
+        $this->resetMethods = $resetMethods;
+    }
+
+    public function onKernelTerminate()
+    {
+        foreach ($this->services as $id => $service) {
+            $method = $this->resetMethods[$id];
+            $service->$method();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getSubscribedEvents()
+    {
+        return array(
+            KernelEvents::TERMINATE => array('onKernelTerminate', -2048),
+        );
+    }
+}

src/Symfony/Component/HttpKernel/Tests/DependencyInjection/ResettableServicePassTest.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace Symfony\Component\HttpKernel\Tests\DependencyInjection;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\HttpKernel\DependencyInjection\ResettableServicePass;
+use Symfony\Component\HttpKernel\EventListener\ServiceResetListener;
+use Symfony\Component\HttpKernel\Tests\Fixtures\ClearableService;
+use Symfony\Component\HttpKernel\Tests\Fixtures\ResettableService;
+
+class ResettableServicePassTest extends TestCase
+{
+    public function testCompilerPass()
+    {
+        $container = new ContainerBuilder();
+        $container->register('one', ResettableService::class)
+            ->addTag('kernel.reset', array('method' => 'reset'));
+        $container->register('two', ClearableService::class)
+            ->addTag('kernel.reset', array('method' => 'clear'));
+
+        $container->register(ServiceResetListener::class)
+            ->setArguments(array(null, array()));
+        $container->addCompilerPass(new ResettableServicePass('kernel.reset'));
+
+        $container->compile();
+
+        $definition = $container->getDefinition(ServiceResetListener::class);
+
+        $this->assertEquals(
+            array(
+                new IteratorArgument(array(
+                    'one' => new Reference('one', ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE),
+                    'two' => new Reference('two', ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE),
+                )),
+                array(
+                    'one' => 'reset',
+                    'two' => 'clear',
+                ),
+            ),
+            $definition->getArguments()
+        );
+    }
+
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
+     * @expectedExceptionMessage Tag kernel.reset requires the "method" attribute to be set.
+     */
+    public function testMissingMethod()
+    {
+        $container = new ContainerBuilder();
+        $container->register(ResettableService::class)
+            ->addTag('kernel.reset');
+        $container->register(ServiceResetListener::class)
+            ->setArguments(array(null, array()));
+        $container->addCompilerPass(new ResettableServicePass('kernel.reset'));
+
+        $container->compile();
+    }
+
+    public function testCompilerPassWithoutResetters()
+    {
+        $container = new ContainerBuilder();
+        $container->register(ServiceResetListener::class)
+            ->setArguments(array(null, array()));
+        $container->addCompilerPass(new ResettableServicePass());
+
+        $container->compile();
+
+        $this->assertFalse($container->has(ServiceResetListener::class));
+    }
+
+    public function testCompilerPassWithoutListener()
+    {
+        $container = new ContainerBuilder();
+        $container->addCompilerPass(new ResettableServicePass());
+
+        $container->compile();
+
+        $this->assertFalse($container->has(ServiceResetListener::class));
+    }
+}

src/Symfony/Component/HttpKernel/Tests/EventListener/ServiceResetListenerTest.php

@@ -0,0 +1,76 @@
+<?php
+
+namespace Symfony\Component\HttpKernel\Tests\EventListener;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\HttpKernel\EventListener\ServiceResetListener;
+use Symfony\Component\HttpKernel\Tests\Fixtures\ClearableService;
+use Symfony\Component\HttpKernel\Tests\Fixtures\ResettableService;
+
+class ServiceResetListenerTest extends TestCase
+{
+    protected function setUp()
+    {
+        ResettableService::$counter = 0;
+        ClearableService::$counter = 0;
+    }
+
+    public function testResetServicesNoOp()
+    {
+        $container = $this->buildContainer();
+        $container->get('reset_subscriber')->onKernelTerminate();
+
+        $this->assertEquals(0, ResettableService::$counter);
+        $this->assertEquals(0, ClearableService::$counter);
+    }
+
+    public function testResetServicesPartially()
+    {
+        $container = $this->buildContainer();
+        $container->get('one');
+        $container->get('reset_subscriber')->onKernelTerminate();
+
+        $this->assertEquals(1, ResettableService::$counter);
+        $this->assertEquals(0, ClearableService::$counter);
+    }
+
+    public function testResetServicesTwice()
+    {
+        $container = $this->buildContainer();
+        $container->get('one');
+        $container->get('reset_subscriber')->onKernelTerminate();
+        $container->get('two');
+        $container->get('reset_subscriber')->onKernelTerminate();
+
+        $this->assertEquals(2, ResettableService::$counter);
+        $this->assertEquals(1, ClearableService::$counter);
+    }
+
+    /**
+     * @return ContainerBuilder
+     */
+    private function buildContainer()
+    {
+        $container = new ContainerBuilder();
+        $container->register('one', ResettableService::class);
+        $container->register('two', ClearableService::class);
+
+        $container->register('reset_subscriber', ServiceResetListener::class)
+            ->addArgument(new IteratorArgument(array(
+                'one' => new Reference('one', ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE),
+                'two' => new Reference('two', ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE),
+            )))
+            ->addArgument(array(
+                'one' => 'reset',
+                'two' => 'clear',
+            ));
+
+        $container->compile();
+
+        return $container;
+    }
+}

src/Symfony/Component/HttpKernel/Tests/Fixtures/ClearableService.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\HttpKernel\Tests\Fixtures;
+
+class ClearableService
+{
+    public static $counter = 0;
+
+    public function clear()
+    {
+        ++self::$counter;
+    }
+}

src/Symfony/Component/HttpKernel/Tests/Fixtures/ResettableService.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\HttpKernel\Tests\Fixtures;
+
+class ResettableService
+{
+    public static $counter = 0;
+
+    public function reset()
+    {
+        ++self::$counter;
+    }
+}