feature #24289 [FrameworkBundle][HttpKernel] Reset profiler (derrabus)

This PR was merged into the 3.4 branch.

Discussion
----------

[FrameworkBundle][HttpKernel] Reset profiler

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #18244
| License       | MIT
| Doc PR        | N/A

This PR adds the ability to reset the profiler between requests. Furthermore, the profiler service has been tagged with the new `kernel.reset` tag from #24155. For this, I had to readd the ability to define multiple reset methods for a service.

Note: This PR requires twigphp/Twig#2560.

Commits
-------

8c39bf7845 Reset profiler.

UPGRADE-3.4.md

@@ -63,6 +63,12 @@ Debug
 
  * Support for stacked errors in the `ErrorHandler` is deprecated and will be removed in Symfony 4.0.
 
+EventDispatcher
+---------------
+
+ * Implementing `TraceableEventDispatcherInterface` without the `reset()` method
+   is deprecated and will be unsupported in 4.0.
+
 Filesystem
 ----------
 
@@ -270,6 +276,10 @@ HttpKernel
 
  * The `Symfony\Component\HttpKernel\Config\EnvParametersResource` class has been deprecated and will be removed in 4.0.
 
+ * Implementing `DataCollectorInterface` without a `reset()` method has been deprecated and will be unsupported in 4.0.
+
+ * Implementing `DebugLoggerInterface` without a `clear()` method has been deprecated and will be unsupported in 4.0.
+
  * The `ChainCacheClearer::add()` method has been deprecated and will be removed in 4.0,
    inject the list of clearers as a constructor argument instead.
 

UPGRADE-4.0.md

@@ -192,6 +192,8 @@ EventDispatcher
  * The `ContainerAwareEventDispatcher` class has been removed.
    Use `EventDispatcher` with closure factories instead.
 
+ * The `reset()` method has been added to `TraceableEventDispatcherInterface`.
+
 ExpressionLanguage
 ------------------
 
@@ -611,6 +613,10 @@ HttpKernel
 
  * The `Symfony\Component\HttpKernel\Config\EnvParametersResource` class has been removed.
 
+ * The `reset()` method has been added to `Symfony\Component\HttpKernel\DataCollector\DataCollectorInterface`.
+
+ * The `clear()` method has been added to `Symfony\Component\HttpKernel\Log\DebugLoggerInterface`.
+
  * The `ChainCacheClearer::add()` method has been removed,
    inject the list of clearers as a constructor argument instead.
 

composer.json

@@ -20,7 +20,7 @@
         "ext-xml": "*",
         "doctrine/common": "~2.4",
         "fig/link-util": "^1.0",
-        "twig/twig": "~1.34|~2.4",
+        "twig/twig": "^1.35|^2.4.4",
         "psr/cache": "~1.0",
         "psr/container": "^1.0",
         "psr/link": "^1.0",

src/Symfony/Bridge/Doctrine/DataCollector/DoctrineDataCollector.php

@@ -28,6 +28,10 @@ class DoctrineDataCollector extends DataCollector
     private $registry;
     private $connections;
     private $managers;
+
+    /**
+     * @var DebugStack[]
+     */
     private $loggers = array();
 
     public function __construct(ManagerRegistry $registry)
@@ -65,6 +69,16 @@ class DoctrineDataCollector extends DataCollector
         );
     }
 
+    public function reset()
+    {
+        $this->data = array();
+
+        foreach ($this->loggers as $logger) {
+            $logger->queries = array();
+            $logger->currentQuery = 0;
+        }
+    }
+
     public function getManagers()
     {
         return $this->data['managers'];

src/Symfony/Bridge/Doctrine/Tests/DataCollector/DoctrineDataCollectorTest.php

@@ -101,6 +101,20 @@ class DoctrineDataCollectorTest extends TestCase
         $this->assertTrue($collectedQueries['default'][1]['explainable']);
     }
 
+    public function testReset()
+    {
+        $queries = array(
+            array('sql' => 'SELECT * FROM table1', 'params' => array(), 'types' => array(), 'executionMS' => 1),
+        );
+        $c = $this->createCollector($queries);
+        $c->collect(new Request(), new Response());
+
+        $c->reset();
+        $c->collect(new Request(), new Response());
+
+        $this->assertEquals(array('default' => array()), $c->getQueries());
+    }
+
     /**
      * @dataProvider paramProvider
      */

src/Symfony/Bridge/Monolog/Logger.php

@@ -45,6 +45,16 @@ class Logger extends BaseLogger implements DebugLoggerInterface
         return 0;
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function clear()
+    {
+        if (($logger = $this->getDebugLogger()) && method_exists($logger, 'clear')) {
+            $logger->clear();
+        }
+    }
+
     /**
      * Returns a DebugLoggerInterface instance if one is registered with this logger.
      *

src/Symfony/Bridge/Monolog/Processor/DebugProcessor.php

@@ -55,4 +55,13 @@ class DebugProcessor implements DebugLoggerInterface
     {
         return $this->errorCount;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function clear()
+    {
+        $this->records = array();
+        $this->errorCount = 0;
+    }
 }

src/Symfony/Bridge/Monolog/Tests/LoggerTest.php

@@ -128,4 +128,17 @@ class LoggerTest extends TestCase
         $this->assertEquals('test', $record['message']);
         $this->assertEquals(Logger::INFO, $record['priority']);
     }
+
+    public function testClear()
+    {
+        $handler = new TestHandler();
+        $logger = new Logger('test', array($handler));
+        $logger->pushProcessor(new DebugProcessor());
+
+        $logger->addInfo('test');
+        $logger->clear();
+
+        $this->assertEmpty($logger->getLogs());
+        $this->assertSame(0, $logger->countErrors());
+    }
 }

src/Symfony/Bridge/Twig/DataCollector/TwigDataCollector.php

@@ -44,6 +44,16 @@ class TwigDataCollector extends DataCollector implements LateDataCollectorInterf
     {
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->profile->reset();
+        $this->computed = null;
+        $this->data = array();
+    }
+
     /**
      * {@inheritdoc}
      */

src/Symfony/Bridge/Twig/composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": "^5.5.9|>=7.0.8",
-        "twig/twig": "~1.34|~2.4"
+        "twig/twig": "^1.35|^2.4.4"
     },
     "require-dev": {
         "fig/link-util": "^1.0",

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -609,9 +609,9 @@ class FrameworkExtension extends Extension
             }
         }
 
-        if (!$config['collect']) {
-            $container->getDefinition('profiler')->addMethodCall('disable', array());
-        }
+        $container->getDefinition('profiler')
+            ->addArgument($config['collect'])
+            ->addTag('kernel.reset', array('method' => 'reset'));
     }
 
     /**

src/Symfony/Bundle/SecurityBundle/DataCollector/SecurityDataCollector.php

@@ -203,6 +203,14 @@ class SecurityDataCollector extends DataCollector implements LateDataCollectorIn
         }
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array();
+    }
+
     public function lateCollect()
     {
         $this->data = $this->cloneVar($this->data);

src/Symfony/Component/Cache/DataCollector/CacheDataCollector.php

@@ -53,6 +53,15 @@ class CacheDataCollector extends DataCollector implements LateDataCollectorInter
         $this->data['total']['statistics'] = $this->calculateTotalStatistics();
     }
 
+    public function reset()
+    {
+        $this->data = array();
+        foreach ($this->instances as $instance) {
+            // Calling getCalls() will clear the calls.
+            $instance->getCalls();
+        }
+    }
+
     public function lateCollect()
     {
         $this->data = $this->cloneVar($this->data);

src/Symfony/Component/EventDispatcher/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+3.4.0
+-----
+
+  * Implementing `TraceableEventDispatcherInterface` without the `reset()` method has been deprecated.
+
 3.3.0
 -----
 

src/Symfony/Component/EventDispatcher/Debug/TraceableEventDispatcher.php

@@ -212,6 +212,11 @@ class TraceableEventDispatcher implements TraceableEventDispatcherInterface
         return $notCalled;
     }
 
+    public function reset()
+    {
+        $this->called = array();
+    }
+
     /**
      * Proxies all method calls to the original event dispatcher.
      *

src/Symfony/Component/EventDispatcher/Debug/TraceableEventDispatcherInterface.php

@@ -15,6 +15,8 @@ use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @method reset() Resets the trace.
  */
 interface TraceableEventDispatcherInterface extends EventDispatcherInterface
 {

src/Symfony/Component/EventDispatcher/Tests/Debug/TraceableEventDispatcherTest.php

@@ -124,6 +124,21 @@ class TraceableEventDispatcherTest extends TestCase
         $this->assertEquals(array(), $tdispatcher->getNotCalledListeners());
     }
 
+    public function testClearCalledListeners()
+    {
+        $tdispatcher = new TraceableEventDispatcher(new EventDispatcher(), new Stopwatch());
+        $tdispatcher->addListener('foo', function () {}, 5);
+
+        $tdispatcher->dispatch('foo');
+        $tdispatcher->reset();
+
+        $listeners = $tdispatcher->getNotCalledListeners();
+        $this->assertArrayHasKey('stub', $listeners['foo.closure']);
+        unset($listeners['foo.closure']['stub']);
+        $this->assertEquals(array(), $tdispatcher->getCalledListeners());
+        $this->assertEquals(array('foo.closure' => array('event' => 'foo', 'pretty' => 'closure', 'priority' => 5)), $listeners);
+    }
+
     public function testGetCalledListenersNested()
     {
         $tdispatcher = null;

src/Symfony/Component/Form/Extension/DataCollector/FormDataCollector.php

@@ -72,12 +72,9 @@ class FormDataCollector extends DataCollector implements FormDataCollectorInterf
     public function __construct(FormDataExtractorInterface $dataExtractor)
     {
         $this->dataExtractor = $dataExtractor;
-        $this->data = array(
-            'forms' => array(),
-            'forms_by_hash' => array(),
-            'nb_errors' => 0,
-        );
         $this->hasVarDumper = class_exists(ClassStub::class);
+
+        $this->reset();
     }
 
     /**
@@ -87,6 +84,15 @@ class FormDataCollector extends DataCollector implements FormDataCollectorInterf
     {
     }
 
+    public function reset()
+    {
+        $this->data = array(
+            'forms' => array(),
+            'forms_by_hash' => array(),
+            'nb_errors' => 0,
+        );
+    }
+
     /**
      * {@inheritdoc}
      */

src/Symfony/Component/Form/Tests/Extension/DataCollector/FormDataCollectorTest.php

@@ -695,6 +695,36 @@ class FormDataCollectorTest extends TestCase
         $this->assertFalse(isset($child21Data['has_children_error']), 'The leaf data does not contains "has_children_error" property.');
     }
 
+    public function testReset()
+    {
+        $form = $this->createForm('my_form');
+
+        $this->dataExtractor->expects($this->any())
+            ->method('extractConfiguration')
+            ->will($this->returnValue(array()));
+        $this->dataExtractor->expects($this->any())
+            ->method('extractDefaultData')
+            ->will($this->returnValue(array()));
+        $this->dataExtractor->expects($this->any())
+            ->method('extractSubmittedData')
+            ->with($form)
+            ->will($this->returnValue(array('errors' => array('baz'))));
+
+        $this->dataCollector->buildPreliminaryFormTree($form);
+        $this->dataCollector->collectSubmittedData($form);
+
+        $this->dataCollector->reset();
+
+        $this->assertSame(
+            array(
+                'forms' => array(),
+                'forms_by_hash' => array(),
+                'nb_errors' => 0,
+            ),
+            $this->dataCollector->getData()
+        );
+    }
+
     private function createForm($name)
     {
         $builder = new FormBuilder($name, null, $this->dispatcher, $this->factory);

src/Symfony/Component/HttpKernel/CHANGELOG.md

@@ -14,7 +14,9 @@ CHANGELOG
  * deprecated the `ChainCacheClearer::add()` method
  * deprecated the `CacheaWarmerAggregate::add()` and `setWarmers()` methods
  * made `CacheWarmerAggregate` and `ChainCacheClearer` classes final
-
+ * added the possibility to reset the profiler to its initial state
+ * deprecated data collectors without a `reset()` method
+ * deprecated implementing `DebugLoggerInterface` without a `clear()` method
 
 3.3.0
 -----

src/Symfony/Component/HttpKernel/DataCollector/AjaxDataCollector.php

@@ -26,6 +26,11 @@ class AjaxDataCollector extends DataCollector
         // all collecting is done client side
     }
 
+    public function reset()
+    {
+        // all collecting is done client side
+    }
+
     public function getName()
     {
         return 'ajax';

src/Symfony/Component/HttpKernel/DataCollector/ConfigDataCollector.php

@@ -95,6 +95,14 @@ class ConfigDataCollector extends DataCollector implements LateDataCollectorInte
         }
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array();
+    }
+
     public function lateCollect()
     {
         $this->data = $this->cloneVar($this->data);

src/Symfony/Component/HttpKernel/DataCollector/DataCollectorInterface.php

@@ -18,6 +18,8 @@ use Symfony\Component\HttpFoundation\Response;
  * DataCollectorInterface.
  *
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @method reset() Resets this data collector to its initial state.
  */
 interface DataCollectorInterface
 {

src/Symfony/Component/HttpKernel/DataCollector/EventDataCollector.php

@@ -27,6 +27,9 @@ class EventDataCollector extends DataCollector implements LateDataCollectorInter
 
     public function __construct(EventDispatcherInterface $dispatcher = null)
     {
+        if ($dispatcher instanceof TraceableEventDispatcherInterface && !method_exists($dispatcher, 'reset')) {
+            @trigger_error(sprintf('Implementing "%s" without the "reset()" method is deprecated since version 3.4 and will be unsupported in 4.0 for class "%s".', TraceableEventDispatcherInterface::class, \get_class($dispatcher)), E_USER_DEPRECATED);
+        }
         $this->dispatcher = $dispatcher;
     }
 
@@ -41,6 +44,19 @@ class EventDataCollector extends DataCollector implements LateDataCollectorInter
         );
     }
 
+    public function reset()
+    {
+        $this->data = array();
+
+        if ($this->dispatcher instanceof TraceableEventDispatcherInterface) {
+            if (!method_exists($this->dispatcher, 'reset')) {
+                return; // @deprecated
+            }
+
+            $this->dispatcher->reset();
+        }
+    }
+
     public function lateCollect()
     {
         if ($this->dispatcher instanceof TraceableEventDispatcherInterface) {

src/Symfony/Component/HttpKernel/DataCollector/ExceptionDataCollector.php

@@ -34,6 +34,14 @@ class ExceptionDataCollector extends DataCollector
         }
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array();
+    }
+
     /**
      * Checks if the exception is not null.
      *

src/Symfony/Component/HttpKernel/DataCollector/LoggerDataCollector.php

@@ -29,6 +29,10 @@ class LoggerDataCollector extends DataCollector implements LateDataCollectorInte
     public function __construct($logger = null, $containerPathPrefix = null)
     {
         if (null !== $logger && $logger instanceof DebugLoggerInterface) {
+            if (!method_exists($logger, 'clear')) {
+                @trigger_error(sprintf('Implementing "%s" without the "clear()" method is deprecated since version 3.4 and will be unsupported in 4.0 for class "%s".', DebugLoggerInterface::class, \get_class($logger)), E_USER_DEPRECATED);
+            }
+
             $this->logger = $logger;
         }
 
@@ -43,6 +47,17 @@ class LoggerDataCollector extends DataCollector implements LateDataCollectorInte
         // everything is done as late as possible
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        if ($this->logger && method_exists($this->logger, 'clear')) {
+            $this->logger->clear();
+        }
+        $this->data = array();
+    }
+
     /**
      * {@inheritdoc}
      */

src/Symfony/Component/HttpKernel/DataCollector/MemoryDataCollector.php

@@ -23,10 +23,7 @@ class MemoryDataCollector extends DataCollector implements LateDataCollectorInte
 {
     public function __construct()
     {
-        $this->data = array(
-            'memory' => 0,
-            'memory_limit' => $this->convertToBytes(ini_get('memory_limit')),
-        );
+        $this->reset();
     }
 
     /**
@@ -37,6 +34,17 @@ class MemoryDataCollector extends DataCollector implements LateDataCollectorInte
         $this->updateMemoryUsage();
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array(
+            'memory' => 0,
+            'memory_limit' => $this->convertToBytes(ini_get('memory_limit')),
+        );
+    }
+
     /**
      * {@inheritdoc}
      */

src/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php

@@ -156,6 +156,12 @@ class RequestDataCollector extends DataCollector implements EventSubscriberInter
         $this->data = $this->cloneVar($this->data);
     }
 
+    public function reset()
+    {
+        $this->data = array();
+        $this->controllers = new \SplObjectStorage();
+    }
+
     public function getMethod()
     {
         return $this->data['method'];

src/Symfony/Component/HttpKernel/DataCollector/RouterDataCollector.php

@@ -23,17 +23,14 @@ use Symfony\Component\HttpKernel\Event\FilterControllerEvent;
  */
 class RouterDataCollector extends DataCollector
 {
+    /**
+     * @var \SplObjectStorage
+     */
     protected $controllers;
 
     public function __construct()
     {
-        $this->controllers = new \SplObjectStorage();
-
-        $this->data = array(
-            'redirect' => false,
-            'url' => null,
-            'route' => null,
-        );
+        $this->reset();
     }
 
     /**
@@ -53,6 +50,17 @@ class RouterDataCollector extends DataCollector
         unset($this->controllers[$request]);
     }
 
+    public function reset()
+    {
+        $this->controllers = new \SplObjectStorage();
+
+        $this->data = array(
+            'redirect' => false,
+            'url' => null,
+            'route' => null,
+        );
+    }
+
     protected function guessRoute(Request $request, $controller)
     {
         return 'n/a';

src/Symfony/Component/HttpKernel/DataCollector/TimeDataCollector.php

@@ -49,6 +49,14 @@ class TimeDataCollector extends DataCollector implements LateDataCollectorInterf
         );
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array();
+    }
+
     /**
      * {@inheritdoc}
      */

src/Symfony/Component/HttpKernel/Log/DebugLoggerInterface.php

@@ -15,6 +15,8 @@ namespace Symfony\Component\HttpKernel\Log;
  * DebugLoggerInterface.
  *
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @method clear() Removes all log records.
  */
 interface DebugLoggerInterface
 {

src/Symfony/Component/HttpKernel/Profiler/Profiler.php

@@ -40,6 +40,11 @@ class Profiler
      */
     private $logger;
 
+    /**
+     * @var bool
+     */
+    private $initiallyEnabled = true;
+
     /**
      * @var bool
      */
@@ -48,11 +53,13 @@ class Profiler
     /**
      * @param ProfilerStorageInterface $storage A ProfilerStorageInterface instance
      * @param LoggerInterface          $logger  A LoggerInterface instance
+     * @param bool                     $enable  The initial enabled state
      */
-    public function __construct(ProfilerStorageInterface $storage, LoggerInterface $logger = null)
+    public function __construct(ProfilerStorageInterface $storage, LoggerInterface $logger = null, $enable = true)
     {
         $this->storage = $storage;
         $this->logger = $logger;
+        $this->initiallyEnabled = $this->enabled = (bool) $enable;
     }
 
     /**
@@ -188,6 +195,18 @@ class Profiler
         return $profile;
     }
 
+    public function reset()
+    {
+        foreach ($this->collectors as $collector) {
+            if (!method_exists($collector, 'reset')) {
+                continue;
+            }
+
+            $collector->reset();
+        }
+        $this->enabled = $this->initiallyEnabled;
+    }
+
     /**
      * Gets the Collectors associated with this profiler.
      *
@@ -218,6 +237,10 @@ class Profiler
      */
     public function add(DataCollectorInterface $collector)
     {
+        if (!method_exists($collector, 'reset')) {
+            @trigger_error(sprintf('Implementing "%s" without the "reset()" method is deprecated since version 3.4 and will be unsupported in 4.0 for class "%s".', DataCollectorInterface::class, \get_class($collector)), E_USER_DEPRECATED);
+        }
+
         $this->collectors[$collector->getName()] = $collector;
     }
 

src/Symfony/Component/HttpKernel/Tests/DataCollector/ExceptionDataCollectorTest.php

@@ -37,4 +37,23 @@ class ExceptionDataCollectorTest extends TestCase
         $this->assertSame('exception', $c->getName());
         $this->assertSame($trace, $c->getTrace());
     }
+
+    public function testCollectWithoutException()
+    {
+        $c = new ExceptionDataCollector();
+        $c->collect(new Request(), new Response());
+
+        $this->assertFalse($c->hasException());
+    }
+
+    public function testReset()
+    {
+        $c = new ExceptionDataCollector();
+
+        $c->collect(new Request(), new Response(), new \Exception());
+        $c->reset();
+        $c->collect(new Request(), new Response());
+
+        $this->assertFalse($c->hasException());
+    }
 }

src/Symfony/Component/HttpKernel/Tests/DataCollector/LoggerDataCollectorTest.php

@@ -19,7 +19,10 @@ class LoggerDataCollectorTest extends TestCase
 {
     public function testCollectWithUnexpectedFormat()
     {
-        $logger = $this->getMockBuilder('Symfony\Component\HttpKernel\Log\DebugLoggerInterface')->getMock();
+        $logger = $this
+            ->getMockBuilder('Symfony\Component\HttpKernel\Log\DebugLoggerInterface')
+            ->setMethods(array('countErrors', 'getLogs', 'clear'))
+            ->getMock();
         $logger->expects($this->once())->method('countErrors')->will($this->returnValue('foo'));
         $logger->expects($this->exactly(2))->method('getLogs')->will($this->returnValue(array()));
 
@@ -43,7 +46,10 @@ class LoggerDataCollectorTest extends TestCase
      */
     public function testCollect($nb, $logs, $expectedLogs, $expectedDeprecationCount, $expectedScreamCount, $expectedPriorities = null)
     {
-        $logger = $this->getMockBuilder('Symfony\Component\HttpKernel\Log\DebugLoggerInterface')->getMock();
+        $logger = $this
+            ->getMockBuilder('Symfony\Component\HttpKernel\Log\DebugLoggerInterface')
+            ->setMethods(array('countErrors', 'getLogs', 'clear'))
+            ->getMock();
         $logger->expects($this->once())->method('countErrors')->will($this->returnValue($nb));
         $logger->expects($this->exactly(2))->method('getLogs')->will($this->returnValue($logs));
 
@@ -70,6 +76,18 @@ class LoggerDataCollectorTest extends TestCase
         }
     }
 
+    public function testReset()
+    {
+        $logger = $this
+            ->getMockBuilder('Symfony\Component\HttpKernel\Log\DebugLoggerInterface')
+            ->setMethods(array('countErrors', 'getLogs', 'clear'))
+            ->getMock();
+        $logger->expects($this->once())->method('clear');
+
+        $c = new LoggerDataCollector($logger);
+        $c->reset();
+    }
+
     public function getCollectTestData()
     {
         yield 'simple log' => array(

src/Symfony/Component/HttpKernel/Tests/Fixtures/DataCollector/CloneVarDataCollector.php

@@ -29,6 +29,11 @@ class CloneVarDataCollector extends DataCollector
         $this->data = $this->cloneVar($this->varToClone);
     }
 
+    public function reset()
+    {
+        $this->data = array();
+    }
+
     public function getData()
     {
         return $this->data;

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

@@ -25,4 +25,8 @@ class TestEventDispatcher extends EventDispatcher implements TraceableEventDispa
     {
         return array('bar');
     }
+
+    public function reset()
+    {
+    }
 }

src/Symfony/Component/HttpKernel/Tests/Profiler/ProfilerTest.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\HttpKernel\Tests\Profiler;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpKernel\DataCollector\DataCollectorInterface;
 use Symfony\Component\HttpKernel\DataCollector\RequestDataCollector;
 use Symfony\Component\HttpKernel\Profiler\FileProfilerStorage;
 use Symfony\Component\HttpKernel\Profiler\Profiler;
@@ -40,6 +41,19 @@ class ProfilerTest extends TestCase
         $this->assertSame('bar', $profile->getCollector('request')->getRequestQuery()->all()['foo']->getValue());
     }
 
+    public function testReset()
+    {
+        $collector = $this->getMockBuilder(DataCollectorInterface::class)
+            ->setMethods(['collect', 'getName', 'reset'])
+            ->getMock();
+        $collector->expects($this->any())->method('getName')->willReturn('mock');
+        $collector->expects($this->once())->method('reset');
+
+        $profiler = new Profiler($this->storage);
+        $profiler->add($collector);
+        $profiler->reset();
+    }
+
     public function testFindWorksWithDates()
     {
         $profiler = new Profiler($this->storage);

src/Symfony/Component/Translation/DataCollector/TranslationDataCollector.php

@@ -58,6 +58,14 @@ class TranslationDataCollector extends DataCollector implements LateDataCollecto
     {
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array();
+    }
+
     /**
      * @return array
      */

src/Symfony/Component/Validator/DataCollector/ValidatorDataCollector.php

@@ -19,6 +19,7 @@ use Symfony\Component\HttpKernel\DataCollector\LateDataCollectorInterface;
 use Symfony\Component\Validator\Validator\TraceableValidator;
 use Symfony\Component\VarDumper\Caster\Caster;
 use Symfony\Component\VarDumper\Caster\ClassStub;
+use Symfony\Component\VarDumper\Cloner\Data;
 use Symfony\Component\VarDumper\Cloner\Stub;
 
 /**
@@ -31,10 +32,7 @@ class ValidatorDataCollector extends DataCollector implements LateDataCollectorI
     public function __construct(TraceableValidator $validator)
     {
         $this->validator = $validator;
-        $this->data = array(
-            'calls' => array(),
-            'violations_count' => 0,
-        );
+        $this->reset();
     }
 
     /**
@@ -45,6 +43,15 @@ class ValidatorDataCollector extends DataCollector implements LateDataCollectorI
         // Everything is collected once, on kernel terminate.
     }
 
+    public function reset()
+    {
+        $this->validator->reset();
+        $this->data = array(
+            'calls' => $this->cloneVar(array()),
+            'violations_count' => 0,
+        );
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -52,16 +59,22 @@ class ValidatorDataCollector extends DataCollector implements LateDataCollectorI
     {
         $collected = $this->validator->getCollectedData();
         $this->data['calls'] = $this->cloneVar($collected);
-        $this->data['violations_count'] += array_reduce($collected, function ($previous, $item) {
-            return $previous += count($item['violations']);
+        $this->data['violations_count'] = array_reduce($collected, function ($previous, $item) {
+            return $previous + count($item['violations']);
         }, 0);
     }
 
+    /**
+     * @return Data
+     */
     public function getCalls()
     {
         return $this->data['calls'];
     }
 
+    /**
+     * @return int
+     */
     public function getViolationsCount()
     {
         return $this->data['violations_count'];

src/Symfony/Component/Validator/Tests/DataCollector/ValidatorDataCollectorTest.php

@@ -50,6 +50,33 @@ class ValidatorDataCollectorTest extends TestCase
         $this->assertCount(2, $call['violations']);
     }
 
+    public function testReset()
+    {
+        $originalValidator = $this->createMock(ValidatorInterface::class);
+        $validator = new TraceableValidator($originalValidator);
+
+        $collector = new ValidatorDataCollector($validator);
+
+        $violations = new ConstraintViolationList(array(
+            $this->createMock(ConstraintViolation::class),
+            $this->createMock(ConstraintViolation::class),
+        ));
+        $originalValidator->method('validate')->willReturn($violations);
+
+        $validator->validate(new \stdClass());
+
+        $collector->lateCollect();
+        $collector->reset();
+
+        $this->assertCount(0, $collector->getCalls());
+        $this->assertSame(0, $collector->getViolationsCount());
+
+        $collector->lateCollect();
+
+        $this->assertCount(0, $collector->getCalls());
+        $this->assertSame(0, $collector->getViolationsCount());
+    }
+
     protected function createMock($classname)
     {
         return $this->getMockBuilder($classname)->disableOriginalConstructor()->getMock();

src/Symfony/Component/Validator/Validator/TraceableValidator.php

@@ -11,7 +11,6 @@
 
 namespace Symfony\Component\Validator\Validator;
 
-use Symfony\Component\Validator\ConstraintViolationList;
 use Symfony\Component\Validator\Context\ExecutionContextInterface;
 
 /**
@@ -30,13 +29,18 @@ class TraceableValidator implements ValidatorInterface
     }
 
     /**
-     * @return ConstraintViolationList[]
+     * @return array
      */
     public function getCollectedData()
     {
         return $this->collectedData;
     }
 
+    public function reset()
+    {
+        $this->collectedData = array();
+    }
+
     /**
      * {@inheritdoc}
      */