bug #24709 [HttpKernel] Move services reset to Kernel::handle()+boot(…

…) (nicolas-grekas)

This PR was merged into the 3.4 branch.

Discussion
----------

[HttpKernel] Move services reset to Kernel::handle()+boot()

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #24552
| License       | MIT
| Doc PR        | -

This is an alternative to #24697 (which uses middlewares).
This PR adds a new `services_resetter` service that the Kernel calls on 2nd root requests to reset services.
Instead of #24697 which plans for optional enabling of the services reset, this approach moves the responsibility of calling the services resetter to the core Kernel class, so that no configuration/middleware/etc. is required at all, and no overhead exists at all for regular requests.

Commits
-------

4501a36 [HttpKernel] Move services reset to Kernel

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

@@ -75,10 +75,6 @@
             <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>
+        <service id="services_resetter" class="Symfony\Component\HttpKernel\DependencyInjection\ServicesResetter" public="true" />
     </services>
 </container>

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

@@ -17,7 +17,6 @@
 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>
@@ -26,9 +25,6 @@ class ResettableServicePass implements CompilerPassInterface
 {
     private $tagName;
 
-    /**
-     * @param string $tagName
-     */
     public function __construct($tagName = 'kernel.reset')
     {
         $this->tagName = $tagName;
@@ -39,7 +35,7 @@ public function __construct($tagName = 'kernel.reset')
      */
     public function process(ContainerBuilder $container)
     {
-        if (!$container->has(ServiceResetListener::class)) {
+        if (!$container->has('services_resetter')) {
             return;
         }
 
@@ -57,13 +53,13 @@ public function process(ContainerBuilder $container)
         }
 
         if (empty($services)) {
-            $container->removeDefinition(ServiceResetListener::class);
+            $container->removeDefinition('services_resetter');
 
             return;
         }
 
-        $container->findDefinition(ServiceResetListener::class)
-            ->replaceArgument(0, new IteratorArgument($services))
-            ->replaceArgument(1, $methods);
+        $container->findDefinition('services_resetter')
+            ->setArgument(0, new IteratorArgument($services))
+            ->setArgument(1, $methods);
     }
 }

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

@@ -0,0 +1,39 @@
+<?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;
+
+/**
+ * Resets provided services.
+ *
+ * @author Alexander M. Turek <me@derrabus.de>
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+class ServicesResetter
+{
+    private $resettableServices;
+    private $resetMethods;
+
+    public function __construct(\Traversable $resettableServices, array $resetMethods)
+    {
+        $this->resettableServices = $resettableServices;
+        $this->resetMethods = $resetMethods;
+    }
+
+    public function reset()
+    {
+        foreach ($this->resettableServices as $id => $service) {
+            $service->{$this->resetMethods[$id]}();
+        }
+    }
+}

src/Symfony/Component/HttpKernel/Kernel.php

@@ -64,6 +64,8 @@ abstract class Kernel implements KernelInterface, RebootableInterface, Terminabl
 
     private $projectDir;
     private $warmupDir;
+    private $requestStackSize = 0;
+    private $resetServices = false;
 
     const VERSION = '3.4.0-DEV';
     const VERSION_ID = 30400;
@@ -99,6 +101,8 @@ public function __clone()
 
         $this->booted = false;
         $this->container = null;
+        $this->requestStackSize = 0;
+        $this->resetServices = false;
     }
 
     /**
@@ -107,8 +111,20 @@ public function __clone()
     public function boot()
     {
         if (true === $this->booted) {
+            if (!$this->requestStackSize && $this->resetServices) {
+                if ($this->container->has('services_resetter')) {
+                    $this->container->get('services_resetter')->reset();
+                }
+                $this->resetServices = false;
+            }
+
             return;
         }
+        if ($this->debug && !isset($_SERVER['SHELL_VERBOSITY'])) {
+            putenv('SHELL_VERBOSITY=3');
+            $_ENV['SHELL_VERBOSITY'] = 3;
+            $_SERVER['SHELL_VERBOSITY'] = 3;
+        }
 
         if ($this->loadClassCache) {
             $this->doLoadClassCache($this->loadClassCache[0], $this->loadClassCache[1]);
@@ -169,24 +185,24 @@ public function shutdown()
         }
 
         $this->container = null;
+        $this->requestStackSize = 0;
+        $this->resetServices = false;
     }
 
     /**
      * {@inheritdoc}
      */
     public function handle(Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true)
     {
-        if (false === $this->booted) {
-            if ($this->debug && !isset($_SERVER['SHELL_VERBOSITY'])) {
-                putenv('SHELL_VERBOSITY=3');
-                $_ENV['SHELL_VERBOSITY'] = 3;
-                $_SERVER['SHELL_VERBOSITY'] = 3;
-            }
+        $this->boot();
+        ++$this->requestStackSize;
+        $this->resetServices = true;
 
-            $this->boot();
+        try {
+            return $this->getHttpKernel()->handle($request, $type, $catch);
+        } finally {
+            --$this->requestStackSize;
         }
-
-        return $this->getHttpKernel()->handle($request, $type, $catch);
     }
 
     /**

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

@@ -8,7 +8,7 @@
 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\DependencyInjection\ServicesResetter;
 use Symfony\Component\HttpKernel\Tests\Fixtures\ClearableService;
 use Symfony\Component\HttpKernel\Tests\Fixtures\ResettableService;
 
@@ -24,14 +24,14 @@ public function testCompilerPass()
             ->setPublic(true)
             ->addTag('kernel.reset', array('method' => 'clear'));
 
-        $container->register(ServiceResetListener::class)
+        $container->register('services_resetter', ServicesResetter::class)
             ->setPublic(true)
             ->setArguments(array(null, array()));
-        $container->addCompilerPass(new ResettableServicePass('kernel.reset'));
+        $container->addCompilerPass(new ResettableServicePass());
 
         $container->compile();
 
-        $definition = $container->getDefinition(ServiceResetListener::class);
+        $definition = $container->getDefinition('services_resetter');
 
         $this->assertEquals(
             array(
@@ -57,32 +57,22 @@ public function testMissingMethod()
         $container = new ContainerBuilder();
         $container->register(ResettableService::class)
             ->addTag('kernel.reset');
-        $container->register(ServiceResetListener::class)
+        $container->register('services_resetter', ServicesResetter::class)
             ->setArguments(array(null, array()));
-        $container->addCompilerPass(new ResettableServicePass('kernel.reset'));
+        $container->addCompilerPass(new ResettableServicePass());
 
         $container->compile();
     }
 
     public function testCompilerPassWithoutResetters()
     {
         $container = new ContainerBuilder();
-        $container->register(ServiceResetListener::class)
+        $container->register('services_resetter', ServicesResetter::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));
+        $this->assertFalse($container->has('services_resetter'));
     }
 }

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

@@ -0,0 +1,42 @@
+<?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\DependencyInjection;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpKernel\DependencyInjection\ServicesResetter;
+use Symfony\Component\HttpKernel\Tests\Fixtures\ClearableService;
+use Symfony\Component\HttpKernel\Tests\Fixtures\ResettableService;
+
+class ServicesResetterTest extends TestCase
+{
+    protected function setUp()
+    {
+        ResettableService::$counter = 0;
+        ClearableService::$counter = 0;
+    }
+
+    public function testResetServices()
+    {
+        $resetter = new ServicesResetter(new \ArrayIterator(array(
+            'id1' => new ResettableService(),
+            'id2' => new ClearableService(),
+        )), array(
+            'id1' => 'reset',
+            'id2' => 'clear',
+        ));
+
+        $resetter->reset();
+
+        $this->assertEquals(1, ResettableService::$counter);
+        $this->assertEquals(1, ClearableService::$counter);
+    }
+}