feature #31065 Add ErrorHandler component (yceruto)

This PR was merged into the 4.4 branch.

Discussion
----------

Add ErrorHandler component

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | no
| Fixed tickets | #25905, #26448
| License       | MIT
| Doc PR        | TODO

Mainly for API-based apps that don't require TwigBundle to get the correct exception response according to the request format (aka `_format` attribute).

![exception_response](https://user-images.githubusercontent.com/2028198/55509651-713dc700-562a-11e9-8b98-bef3b0229397.gif)

✔️ [RFC7807](https://tools.ietf.org/html/rfc7807) compliant for JSON and XML formats.

---

This introduce a new `ErrorRenderer` service that render a `FlattenException` into a given format:
```php
use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRenderer;
use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
use Symfony\Component\ErrorHandler\ErrorRenderer\JsonErrorRenderer;

$renderers = [
    new HtmlErrorRenderer(),
    new JsonErrorRenderer(),
    // ...
];
$errorRenderer = new ErrorRenderer($renderers);

return new Response(
    $errorRenderer->render($exception, $request->getRequestFormat()),
    $exception->getStatusCode(),
    $exception->getHeaders()
);
```

The built-in error renderers are:

| Format | Class |
| --- | --- |
| html | HtmlErrorRenderer |
| json | JsonErrorRenderer |
| xml, atom | XmlErrorRenderer |
| txt | TxtErrorRenderer |

And you can add your own error renderer by implementing the `ErrorRendererInterface` and tagging it with `error_handler.renderer` in your service definition.

Creating your own error renderer for a built-in format will end up replacing the related built-in error renderer.

Demo: https://github.com/yceruto/error-handler-app ([add custom error renderer](06fc647841))

Commits
-------

7057244890 Added ErrorHandler component

src/Symfony/Bundle/FrameworkBundle/Console/Application.php

@@ -19,8 +19,8 @@ use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\ConsoleOutputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Style\SymfonyStyle;
-use Symfony\Component\Debug\Exception\FatalThrowableError;
 use Symfony\Component\DependencyInjection\ContainerAwareInterface;
+use Symfony\Component\ErrorHandler\Exception\FatalThrowableError;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 use Symfony\Component\HttpKernel\Kernel;
 use Symfony\Component\HttpKernel\KernelInterface;

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

@@ -152,6 +152,7 @@ class FrameworkExtension extends Extension
         $loader->load('web.xml');
         $loader->load('services.xml');
         $loader->load('fragment_renderer.xml');
+        $loader->load('error_renderer.xml');
 
         $container->registerAliasForArgument('parameter_bag', PsrContainerInterface::class);
 

src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php

@@ -29,10 +29,11 @@ use Symfony\Component\Cache\DependencyInjection\CachePoolPass;
 use Symfony\Component\Cache\DependencyInjection\CachePoolPrunerPass;
 use Symfony\Component\Config\Resource\ClassExistenceResource;
 use Symfony\Component\Console\DependencyInjection\AddConsoleCommandPass;
-use Symfony\Component\Debug\ErrorHandler;
 use Symfony\Component\DependencyInjection\Compiler\PassConfig;
 use Symfony\Component\DependencyInjection\Compiler\RegisterReverseContainerPass;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\ErrorHandler\DependencyInjection\ErrorHandlerPass;
+use Symfony\Component\ErrorHandler\ErrorHandler;
 use Symfony\Component\EventDispatcher\DependencyInjection\RegisterListenersPass;
 use Symfony\Component\Form\DependencyInjection\FormPass;
 use Symfony\Component\HttpFoundation\Request;
@@ -90,6 +91,7 @@ class FrameworkBundle extends Bundle
             KernelEvents::FINISH_REQUEST,
         ];
 
+        $this->addCompilerPassIfExists($container, ErrorHandlerPass::class);
         $container->addCompilerPass(new LoggerPass(), PassConfig::TYPE_BEFORE_OPTIMIZATION, -32);
         $container->addCompilerPass(new RegisterControllerArgumentLocatorsPass());
         $container->addCompilerPass(new RemoveEmptyControllerArgumentLocatorsPass(), PassConfig::TYPE_BEFORE_REMOVING);

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

@@ -19,9 +19,10 @@
             <argument>null</argument><!-- Log levels map for enabled error levels -->
             <argument>%debug.error_handler.throw_at%</argument>
             <argument>%kernel.debug%</argument>
-            <argument type="service" id="debug.file_link_formatter"></argument>
+            <argument type="service" id="debug.file_link_formatter" />
             <argument>%kernel.debug%</argument>
             <argument>%kernel.charset%</argument>
+            <argument type="service" id="error_handler.error_renderer" on-invalid="null" />
         </service>
 
         <service id="debug.file_link_formatter" class="Symfony\Component\HttpKernel\Debug\FileLinkFormatter">

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

@@ -0,0 +1,39 @@
+<?xml version="1.0" ?>
+
+<container xmlns="http://symfony.com/schema/dic/services"
+           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+           xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd">
+
+    <services>
+        <defaults public="false" />
+
+        <service id="error_handler.error_renderer" class="Symfony\Component\ErrorHandler\DependencyInjection\ErrorRenderer">
+            <argument /> <!-- error renderer locator -->
+        </service>
+
+        <service id="error_handler.renderer.html" class="Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer">
+            <tag name="error_handler.renderer" />
+            <argument>%kernel.debug%</argument>
+            <argument>%kernel.charset%</argument>
+            <argument>%debug.file_link_format%</argument>
+        </service>
+
+        <service id="error_handler.renderer.json" class="Symfony\Component\ErrorHandler\ErrorRenderer\JsonErrorRenderer">
+            <tag name="error_handler.renderer" />
+            <argument>%kernel.debug%</argument>
+        </service>
+
+        <service id="error_handler.renderer.xml" class="Symfony\Component\ErrorHandler\ErrorRenderer\XmlErrorRenderer">
+            <tag name="error_handler.renderer" format="atom" />
+            <tag name="error_handler.renderer" />
+            <argument>%kernel.debug%</argument>
+            <argument>%kernel.charset%</argument>
+        </service>
+
+        <service id="error_handler.renderer.txt" class="Symfony\Component\ErrorHandler\ErrorRenderer\TxtErrorRenderer">
+            <tag name="error_handler.renderer" />
+            <argument>%kernel.debug%</argument>
+            <argument>%kernel.charset%</argument>
+        </service>
+    </services>
+</container>

src/Symfony/Bundle/FrameworkBundle/composer.json

@@ -22,7 +22,7 @@
         "symfony/config": "^4.2|^5.0",
         "symfony/dependency-injection": "^4.4|^5.0",
         "symfony/http-foundation": "^4.3|^5.0",
-        "symfony/http-kernel": "^4.3|^5.0",
+        "symfony/http-kernel": "^4.4|^5.0",
         "symfony/polyfill-mbstring": "~1.0",
         "symfony/filesystem": "^3.4|^4.0|^5.0",
         "symfony/finder": "^3.4|^4.0|^5.0",
@@ -69,6 +69,7 @@
         "symfony/asset": "<3.4",
         "symfony/browser-kit": "<4.3",
         "symfony/console": "<4.3",
+        "symfony/debug": "<4.4",
         "symfony/dotenv": "<4.2",
         "symfony/dom-crawler": "<4.3",
         "symfony/form": "<4.3",

src/Symfony/Bundle/TwigBundle/Controller/ExceptionController.php

@@ -11,7 +11,7 @@
 
 namespace Symfony\Bundle\TwigBundle\Controller;
 
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Log\DebugLoggerInterface;

src/Symfony/Bundle/TwigBundle/Controller/PreviewErrorController.php

@@ -11,7 +11,7 @@
 
 namespace Symfony\Bundle\TwigBundle\Controller;
 
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
 

src/Symfony/Bundle/TwigBundle/DependencyInjection/Compiler/ExceptionListenerPass.php

@@ -28,7 +28,7 @@ class ExceptionListenerPass implements CompilerPassInterface
         }
 
         // register the exception controller only if Twig is enabled and required dependencies do exist
-        if (!class_exists('Symfony\Component\Debug\Exception\FlattenException') || !interface_exists('Symfony\Component\EventDispatcher\EventSubscriberInterface')) {
+        if (!class_exists('Symfony\Component\ErrorHandler\Exception\FlattenException') || !interface_exists('Symfony\Component\EventDispatcher\EventSubscriberInterface')) {
             $container->removeDefinition('twig.exception_listener');
         } elseif ($container->hasParameter('templating.engines')) {
             $engines = $container->getParameter('templating.engines');

src/Symfony/Bundle/TwigBundle/Tests/Controller/ExceptionControllerTest.php

@@ -13,7 +13,7 @@ namespace Symfony\Bundle\TwigBundle\Tests\Controller;
 
 use Symfony\Bundle\TwigBundle\Controller\ExceptionController;
 use Symfony\Bundle\TwigBundle\Tests\TestCase;
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
 use Twig\Environment;
 use Twig\Loader\ArrayLoader;

src/Symfony/Bundle/TwigBundle/Tests/Controller/PreviewErrorControllerTest.php

@@ -13,7 +13,7 @@ namespace Symfony\Bundle\TwigBundle\Tests\Controller;
 
 use Symfony\Bundle\TwigBundle\Controller\PreviewErrorController;
 use Symfony\Bundle\TwigBundle\Tests\TestCase;
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\HttpKernelInterface;

src/Symfony/Bundle/TwigBundle/composer.json

@@ -20,7 +20,7 @@
         "symfony/config": "^4.2|^5.0",
         "symfony/twig-bridge": "^4.4|^5.0",
         "symfony/http-foundation": "^4.3|^5.0",
-        "symfony/http-kernel": "^4.1|^5.0",
+        "symfony/http-kernel": "^4.4|^5.0",
         "symfony/polyfill-ctype": "~1.8",
         "twig/twig": "~1.41|~2.10"
     },

src/Symfony/Bundle/WebProfilerBundle/Controller/ExceptionController.php

@@ -11,7 +11,7 @@
 
 namespace Symfony\Bundle\WebProfilerBundle\Controller;
 
-use Symfony\Component\Debug\ExceptionHandler;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Debug\FileLinkFormatter;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
@@ -30,14 +30,18 @@ class ExceptionController
     protected $twig;
     protected $debug;
     protected $profiler;
-    private $fileLinkFormat;
+    private $errorRenderer;
 
-    public function __construct(Profiler $profiler = null, Environment $twig, bool $debug, FileLinkFormatter $fileLinkFormat = null)
+    public function __construct(Profiler $profiler = null, Environment $twig, bool $debug, FileLinkFormatter $fileLinkFormat = null, HtmlErrorRenderer $errorRenderer = null)
     {
         $this->profiler = $profiler;
         $this->twig = $twig;
         $this->debug = $debug;
-        $this->fileLinkFormat = $fileLinkFormat;
+        $this->errorRenderer = $errorRenderer;
+
+        if (null === $errorRenderer) {
+            $this->errorRenderer = new HtmlErrorRenderer($debug, $this->twig->getCharset(), $fileLinkFormat);
+        }
     }
 
     /**
@@ -61,9 +65,7 @@ class ExceptionController
         $template = $this->getTemplate();
 
         if (!$this->twig->getLoader()->exists($template)) {
-            $handler = new ExceptionHandler($this->debug, $this->twig->getCharset(), $this->fileLinkFormat);
-
-            return new Response($handler->getContent($exception), 200, ['Content-Type' => 'text/html']);
+            return new Response($this->errorRenderer->getBody($exception), 200, ['Content-Type' => 'text/html']);
         }
 
         $code = $exception->getStatusCode();
@@ -97,13 +99,10 @@ class ExceptionController
 
         $this->profiler->disable();
 
-        $exception = $this->profiler->loadProfile($token)->getCollector('exception')->getException();
         $template = $this->getTemplate();
 
         if (!$this->templateExists($template)) {
-            $handler = new ExceptionHandler($this->debug, $this->twig->getCharset(), $this->fileLinkFormat);
-
-            return new Response($handler->getStylesheet($exception), 200, ['Content-Type' => 'text/css']);
+            return new Response($this->errorRenderer->getStylesheet(), 200, ['Content-Type' => 'text/css']);
         }
 
         return new Response($this->twig->render('@WebProfiler/Collector/exception.css.twig'), 200, ['Content-Type' => 'text/css']);

src/Symfony/Bundle/WebProfilerBundle/Resources/config/profiler.xml

@@ -27,6 +27,7 @@
             <argument type="service" id="twig" />
             <argument>%kernel.debug%</argument>
             <argument type="service" id="debug.file_link_formatter" />
+            <argument type="service" id="error_handler.renderer.html" on-invalid="null" />
         </service>
 
         <service id="web_profiler.csp.handler" class="Symfony\Bundle\WebProfilerBundle\Csp\ContentSecurityPolicyHandler">

src/Symfony/Bundle/WebProfilerBundle/Tests/DependencyInjection/WebProfilerExtensionTest.php

@@ -17,6 +17,7 @@ use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
 use Symfony\Component\EventDispatcher\DependencyInjection\RegisterListenersPass;
 use Symfony\Component\EventDispatcher\EventDispatcher;
 
@@ -53,6 +54,7 @@ class WebProfilerExtensionTest extends TestCase
         $this->kernel = $this->getMockBuilder('Symfony\\Component\\HttpKernel\\KernelInterface')->getMock();
 
         $this->container = new ContainerBuilder();
+        $this->container->register('error_handler.renderer.html', HtmlErrorRenderer::class);
         $this->container->register('event_dispatcher', EventDispatcher::class)->setPublic(true);
         $this->container->register('router', $this->getMockClass('Symfony\\Component\\Routing\\RouterInterface'))->setPublic(true);
         $this->container->register('twig', 'Twig\Environment')->setPublic(true);

src/Symfony/Bundle/WebProfilerBundle/composer.json

@@ -18,7 +18,7 @@
     "require": {
         "php": "^7.1.3",
         "symfony/config": "^4.2|^5.0",
-        "symfony/http-kernel": "^4.3",
+        "symfony/http-kernel": "^4.4",
         "symfony/routing": "^3.4|^4.0|^5.0",
         "symfony/twig-bundle": "^4.2|^5.0",
         "symfony/var-dumper": "^3.4|^4.0|^5.0",

src/Symfony/Component/Console/Application.php

@@ -41,8 +41,8 @@ use Symfony\Component\Console\Output\ConsoleOutput;
 use Symfony\Component\Console\Output\ConsoleOutputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Style\SymfonyStyle;
-use Symfony\Component\Debug\ErrorHandler;
-use Symfony\Component\Debug\Exception\FatalThrowableError;
+use Symfony\Component\ErrorHandler\ErrorHandler;
+use Symfony\Component\ErrorHandler\Exception\FatalThrowableError;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\EventDispatcher\LegacyEventDispatcherProxy;
 

src/Symfony/Component/Debug/BufferingLogger.php

@@ -11,27 +11,13 @@
 
 namespace Symfony\Component\Debug;
 
-use Psr\Log\AbstractLogger;
+use Symfony\Component\ErrorHandler\BufferingLogger as BaseBufferingLogger;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', BufferingLogger::class, BaseBufferingLogger::class), E_USER_DEPRECATED);
 
 /**
- * A buffering logger that stacks logs for later.
- *
- * @author Nicolas Grekas <p@tchwork.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\BufferingLogger instead.
  */
-class BufferingLogger extends AbstractLogger
+class BufferingLogger extends BaseBufferingLogger
 {
-    private $logs = [];
-
-    public function log($level, $message, array $context = [])
-    {
-        $this->logs[] = [$level, $message, $context];
-    }
-
-    public function cleanLogs()
-    {
-        $logs = $this->logs;
-        $this->logs = [];
-
-        return $logs;
-    }
 }

src/Symfony/Component/Debug/CHANGELOG.md

@@ -1,6 +1,18 @@
 CHANGELOG
 =========
 
+4.4.0
+-----
+
+* deprecated the `BufferingLogger`, `ErrorHandler` and `ExceptionHandler` classes, 
+  they have been moved to the `ErrorHandler` component
+* deprecated the `FatalErrorHandlerInterface`, `ClassNotFoundFatalErrorHandler`,  
+  `UndefinedFunctionFatalErrorHandler` and `UndefinedMethodFatalErrorHandler` classes,
+  they have been moved to the `ErrorHandler` component
+* deprecated the `ClassNotFoundException`, `FatalErrorException`, `FatalThrowableError`,
+  `FlattenException`, `OutOfMemoryException`, `SilencedErrorContext`, `UndefinedFunctionException`,
+  and `UndefinedMethodException`, they have been moved to the `ErrorHandler` component
+
 4.3.0
 -----
 

src/Symfony/Component/Debug/Debug.php

@@ -11,6 +11,10 @@
 
 namespace Symfony\Component\Debug;
 
+use Symfony\Component\ErrorHandler\BufferingLogger;
+use Symfony\Component\ErrorHandler\ErrorHandler;
+use Symfony\Component\ErrorHandler\ExceptionHandler;
+
 /**
  * Registers all the debug tools.
  *

src/Symfony/Component/Debug/DebugClassLoader.php

@@ -86,7 +86,7 @@ class DebugClassLoader
     public static function enable()
     {
         // Ensures we don't hit https://bugs.php.net/42098
-        class_exists('Symfony\Component\Debug\ErrorHandler');
+        class_exists('Symfony\Component\ErrorHandler\ErrorHandler');
         class_exists('Psr\Log\LogLevel');
 
         if (!\is_array($functions = spl_autoload_functions())) {

src/Symfony/Component/Debug/ErrorHandler.php

@@ -11,700 +11,13 @@
 
 namespace Symfony\Component\Debug;
 
-use Psr\Log\LoggerInterface;
-use Psr\Log\LogLevel;
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\Exception\FatalThrowableError;
-use Symfony\Component\Debug\Exception\FlattenException;
-use Symfony\Component\Debug\Exception\OutOfMemoryException;
-use Symfony\Component\Debug\Exception\SilencedErrorContext;
-use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
-use Symfony\Component\Debug\FatalErrorHandler\FatalErrorHandlerInterface;
-use Symfony\Component\Debug\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
-use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;
+use Symfony\Component\ErrorHandler\ErrorHandler as BaseErrorHandler;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', ErrorHandler::class, BaseErrorHandler::class), E_USER_DEPRECATED);
 
 /**
- * A generic ErrorHandler for the PHP engine.
- *
- * Provides five bit fields that control how errors are handled:
- * - thrownErrors: errors thrown as \ErrorException
- * - loggedErrors: logged errors, when not @-silenced
- * - scopedErrors: errors thrown or logged with their local context
- * - tracedErrors: errors logged with their stack trace
- * - screamedErrors: never @-silenced errors
- *
- * Each error level can be logged by a dedicated PSR-3 logger object.
- * Screaming only applies to logging.
- * Throwing takes precedence over logging.
- * Uncaught exceptions are logged as E_ERROR.
- * E_DEPRECATED and E_USER_DEPRECATED levels never throw.
- * E_RECOVERABLE_ERROR and E_USER_ERROR levels always throw.
- * Non catchable errors that can be detected at shutdown time are logged when the scream bit field allows so.
- * As errors have a performance cost, repeated errors are all logged, so that the developer
- * can see them and weight them as more important to fix than others of the same level.
- *
- * @author Nicolas Grekas <p@tchwork.com>
- * @author Grégoire Pineau <lyrixx@lyrixx.info>
- *
- * @final since Symfony 4.3
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\ErrorHandler instead.
  */
-class ErrorHandler
+class ErrorHandler extends BaseErrorHandler
 {
-    private $levels = [
-        E_DEPRECATED => 'Deprecated',
-        E_USER_DEPRECATED => 'User Deprecated',
-        E_NOTICE => 'Notice',
-        E_USER_NOTICE => 'User Notice',
-        E_STRICT => 'Runtime Notice',
-        E_WARNING => 'Warning',
-        E_USER_WARNING => 'User Warning',
-        E_COMPILE_WARNING => 'Compile Warning',
-        E_CORE_WARNING => 'Core Warning',
-        E_USER_ERROR => 'User Error',
-        E_RECOVERABLE_ERROR => 'Catchable Fatal Error',
-        E_COMPILE_ERROR => 'Compile Error',
-        E_PARSE => 'Parse Error',
-        E_ERROR => 'Error',
-        E_CORE_ERROR => 'Core Error',
-    ];
-
-    private $loggers = [
-        E_DEPRECATED => [null, LogLevel::INFO],
-        E_USER_DEPRECATED => [null, LogLevel::INFO],
-        E_NOTICE => [null, LogLevel::WARNING],
-        E_USER_NOTICE => [null, LogLevel::WARNING],
-        E_STRICT => [null, LogLevel::WARNING],
-        E_WARNING => [null, LogLevel::WARNING],
-        E_USER_WARNING => [null, LogLevel::WARNING],
-        E_COMPILE_WARNING => [null, LogLevel::WARNING],
-        E_CORE_WARNING => [null, LogLevel::WARNING],
-        E_USER_ERROR => [null, LogLevel::CRITICAL],
-        E_RECOVERABLE_ERROR => [null, LogLevel::CRITICAL],
-        E_COMPILE_ERROR => [null, LogLevel::CRITICAL],
-        E_PARSE => [null, LogLevel::CRITICAL],
-        E_ERROR => [null, LogLevel::CRITICAL],
-        E_CORE_ERROR => [null, LogLevel::CRITICAL],
-    ];
-
-    private $thrownErrors = 0x1FFF; // E_ALL - E_DEPRECATED - E_USER_DEPRECATED
-    private $scopedErrors = 0x1FFF; // E_ALL - E_DEPRECATED - E_USER_DEPRECATED
-    private $tracedErrors = 0x77FB; // E_ALL - E_STRICT - E_PARSE
-    private $screamedErrors = 0x55; // E_ERROR + E_CORE_ERROR + E_COMPILE_ERROR + E_PARSE
-    private $loggedErrors = 0;
-    private $traceReflector;
-
-    private $isRecursive = 0;
-    private $isRoot = false;
-    private $exceptionHandler;
-    private $bootstrappingLogger;
-
-    private static $reservedMemory;
-    private static $toStringException = null;
-    private static $silencedErrorCache = [];
-    private static $silencedErrorCount = 0;
-    private static $exitCode = 0;
-
-    /**
-     * Registers the error handler.
-     *
-     * @param self|null $handler The handler to register
-     * @param bool      $replace Whether to replace or not any existing handler
-     *
-     * @return self The registered error handler
-     */
-    public static function register(self $handler = null, $replace = true)
-    {
-        if (null === self::$reservedMemory) {
-            self::$reservedMemory = str_repeat('x', 10240);
-            register_shutdown_function(__CLASS__.'::handleFatalError');
-        }
-
-        if ($handlerIsNew = null === $handler) {
-            $handler = new static();
-        }
-
-        if (null === $prev = set_error_handler([$handler, 'handleError'])) {
-            restore_error_handler();
-            // Specifying the error types earlier would expose us to https://bugs.php.net/63206
-            set_error_handler([$handler, 'handleError'], $handler->thrownErrors | $handler->loggedErrors);
-            $handler->isRoot = true;
-        }
-
-        if ($handlerIsNew && \is_array($prev) && $prev[0] instanceof self) {
-            $handler = $prev[0];
-            $replace = false;
-        }
-        if (!$replace && $prev) {
-            restore_error_handler();
-            $handlerIsRegistered = \is_array($prev) && $handler === $prev[0];
-        } else {
-            $handlerIsRegistered = true;
-        }
-        if (\is_array($prev = set_exception_handler([$handler, 'handleException'])) && $prev[0] instanceof self) {
-            restore_exception_handler();
-            if (!$handlerIsRegistered) {
-                $handler = $prev[0];
-            } elseif ($handler !== $prev[0] && $replace) {
-                set_exception_handler([$handler, 'handleException']);
-                $p = $prev[0]->setExceptionHandler(null);
-                $handler->setExceptionHandler($p);
-                $prev[0]->setExceptionHandler($p);
-            }
-        } else {
-            $handler->setExceptionHandler($prev);
-        }
-
-        $handler->throwAt(E_ALL & $handler->thrownErrors, true);
-
-        return $handler;
-    }
-
-    public function __construct(BufferingLogger $bootstrappingLogger = null)
-    {
-        if ($bootstrappingLogger) {
-            $this->bootstrappingLogger = $bootstrappingLogger;
-            $this->setDefaultLogger($bootstrappingLogger);
-        }
-        $this->traceReflector = new \ReflectionProperty('Exception', 'trace');
-        $this->traceReflector->setAccessible(true);
-    }
-
-    /**
-     * Sets a logger to non assigned errors levels.
-     *
-     * @param LoggerInterface $logger  A PSR-3 logger to put as default for the given levels
-     * @param array|int       $levels  An array map of E_* to LogLevel::* or an integer bit field of E_* constants
-     * @param bool            $replace Whether to replace or not any existing logger
-     */
-    public function setDefaultLogger(LoggerInterface $logger, $levels = E_ALL, $replace = false)
-    {
-        $loggers = [];
-
-        if (\is_array($levels)) {
-            foreach ($levels as $type => $logLevel) {
-                if (empty($this->loggers[$type][0]) || $replace || $this->loggers[$type][0] === $this->bootstrappingLogger) {
-                    $loggers[$type] = [$logger, $logLevel];
-                }
-            }
-        } else {
-            if (null === $levels) {
-                $levels = E_ALL;
-            }
-            foreach ($this->loggers as $type => $log) {
-                if (($type & $levels) && (empty($log[0]) || $replace || $log[0] === $this->bootstrappingLogger)) {
-                    $log[0] = $logger;
-                    $loggers[$type] = $log;
-                }
-            }
-        }
-
-        $this->setLoggers($loggers);
-    }
-
-    /**
-     * Sets a logger for each error level.
-     *
-     * @param array $loggers Error levels to [LoggerInterface|null, LogLevel::*] map
-     *
-     * @return array The previous map
-     *
-     * @throws \InvalidArgumentException
-     */
-    public function setLoggers(array $loggers)
-    {
-        $prevLogged = $this->loggedErrors;
-        $prev = $this->loggers;
-        $flush = [];
-
-        foreach ($loggers as $type => $log) {
-            if (!isset($prev[$type])) {
-                throw new \InvalidArgumentException('Unknown error type: '.$type);
-            }
-            if (!\is_array($log)) {
-                $log = [$log];
-            } elseif (!\array_key_exists(0, $log)) {
-                throw new \InvalidArgumentException('No logger provided');
-            }
-            if (null === $log[0]) {
-                $this->loggedErrors &= ~$type;
-            } elseif ($log[0] instanceof LoggerInterface) {
-                $this->loggedErrors |= $type;
-            } else {
-                throw new \InvalidArgumentException('Invalid logger provided');
-            }
-            $this->loggers[$type] = $log + $prev[$type];
-
-            if ($this->bootstrappingLogger && $prev[$type][0] === $this->bootstrappingLogger) {
-                $flush[$type] = $type;
-            }
-        }
-        $this->reRegister($prevLogged | $this->thrownErrors);
-
-        if ($flush) {
-            foreach ($this->bootstrappingLogger->cleanLogs() as $log) {
-                $type = $log[2]['exception'] instanceof \ErrorException ? $log[2]['exception']->getSeverity() : E_ERROR;
-                if (!isset($flush[$type])) {
-                    $this->bootstrappingLogger->log($log[0], $log[1], $log[2]);
-                } elseif ($this->loggers[$type][0]) {
-                    $this->loggers[$type][0]->log($this->loggers[$type][1], $log[1], $log[2]);
-                }
-            }
-        }
-
-        return $prev;
-    }
-
-    /**
-     * Sets a user exception handler.
-     *
-     * @param callable $handler A handler that will be called on Exception
-     *
-     * @return callable|null The previous exception handler
-     */
-    public function setExceptionHandler(callable $handler = null)
-    {
-        $prev = $this->exceptionHandler;
-        $this->exceptionHandler = $handler;
-
-        return $prev;
-    }
-
-    /**
-     * Sets the PHP error levels that throw an exception when a PHP error occurs.
-     *
-     * @param int  $levels  A bit field of E_* constants for thrown errors
-     * @param bool $replace Replace or amend the previous value
-     *
-     * @return int The previous value
-     */
-    public function throwAt($levels, $replace = false)
-    {
-        $prev = $this->thrownErrors;
-        $this->thrownErrors = ($levels | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
-        if (!$replace) {
-            $this->thrownErrors |= $prev;
-        }
-        $this->reRegister($prev | $this->loggedErrors);
-
-        return $prev;
-    }
-
-    /**
-     * Sets the PHP error levels for which local variables are preserved.
-     *
-     * @param int  $levels  A bit field of E_* constants for scoped errors
-     * @param bool $replace Replace or amend the previous value
-     *
-     * @return int The previous value
-     */
-    public function scopeAt($levels, $replace = false)
-    {
-        $prev = $this->scopedErrors;
-        $this->scopedErrors = (int) $levels;
-        if (!$replace) {
-            $this->scopedErrors |= $prev;
-        }
-
-        return $prev;
-    }
-
-    /**
-     * Sets the PHP error levels for which the stack trace is preserved.
-     *
-     * @param int  $levels  A bit field of E_* constants for traced errors
-     * @param bool $replace Replace or amend the previous value
-     *
-     * @return int The previous value
-     */
-    public function traceAt($levels, $replace = false)
-    {
-        $prev = $this->tracedErrors;
-        $this->tracedErrors = (int) $levels;
-        if (!$replace) {
-            $this->tracedErrors |= $prev;
-        }
-
-        return $prev;
-    }
-
-    /**
-     * Sets the error levels where the @-operator is ignored.
-     *
-     * @param int  $levels  A bit field of E_* constants for screamed errors
-     * @param bool $replace Replace or amend the previous value
-     *
-     * @return int The previous value
-     */
-    public function screamAt($levels, $replace = false)
-    {
-        $prev = $this->screamedErrors;
-        $this->screamedErrors = (int) $levels;
-        if (!$replace) {
-            $this->screamedErrors |= $prev;
-        }
-
-        return $prev;
-    }
-
-    /**
-     * Re-registers as a PHP error handler if levels changed.
-     */
-    private function reRegister($prev)
-    {
-        if ($prev !== $this->thrownErrors | $this->loggedErrors) {
-            $handler = set_error_handler('var_dump');
-            $handler = \is_array($handler) ? $handler[0] : null;
-            restore_error_handler();
-            if ($handler === $this) {
-                restore_error_handler();
-                if ($this->isRoot) {
-                    set_error_handler([$this, 'handleError'], $this->thrownErrors | $this->loggedErrors);
-                } else {
-                    set_error_handler([$this, 'handleError']);
-                }
-            }
-        }
-    }
-
-    /**
-     * Handles errors by filtering then logging them according to the configured bit fields.
-     *
-     * @return bool Returns false when no handling happens so that the PHP engine can handle the error itself
-     *
-     * @throws \ErrorException When $this->thrownErrors requests so
-     *
-     * @internal
-     */
-    public function handleError(int $type, string $message, string $file, int $line): bool
-    {
-        // @deprecated to be removed in Symfony 5.0
-        if (\PHP_VERSION_ID >= 70300 && $message && '"' === $message[0] && 0 === strpos($message, '"continue') && preg_match('/^"continue(?: \d++)?" targeting switch is equivalent to "break(?: \d++)?"\. Did you mean to use "continue(?: \d++)?"\?$/', $message)) {
-            $type = E_DEPRECATED;
-        }
-
-        // Level is the current error reporting level to manage silent error.
-        $level = error_reporting();
-        $silenced = 0 === ($level & $type);
-        // Strong errors are not authorized to be silenced.
-        $level |= E_RECOVERABLE_ERROR | E_USER_ERROR | E_DEPRECATED | E_USER_DEPRECATED;
-        $log = $this->loggedErrors & $type;
-        $throw = $this->thrownErrors & $type & $level;
-        $type &= $level | $this->screamedErrors;
-
-        if (!$type || (!$log && !$throw)) {
-            return !$silenced && $type && $log;
-        }
-        $scope = $this->scopedErrors & $type;
-
-        if (4 < $numArgs = \func_num_args()) {
-            $context = $scope ? (func_get_arg(4) ?: []) : [];
-        } else {
-            $context = [];
-        }
-
-        if (isset($context['GLOBALS']) && $scope) {
-            $e = $context;                  // Whatever the signature of the method,
-            unset($e['GLOBALS'], $context); // $context is always a reference in 5.3
-            $context = $e;
-        }
-
-        if (false !== strpos($message, "class@anonymous\0")) {
-            $logMessage = $this->levels[$type].': '.(new FlattenException())->setMessage($message)->getMessage();
-        } else {
-            $logMessage = $this->levels[$type].': '.$message;
-        }
-
-        if (null !== self::$toStringException) {
-            $errorAsException = self::$toStringException;
-            self::$toStringException = null;
-        } elseif (!$throw && !($type & $level)) {
-            if (!isset(self::$silencedErrorCache[$id = $file.':'.$line])) {
-                $lightTrace = $this->tracedErrors & $type ? $this->cleanTrace(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 5), $type, $file, $line, false) : [];
-                $errorAsException = new SilencedErrorContext($type, $file, $line, isset($lightTrace[1]) ? [$lightTrace[0]] : $lightTrace);
-            } elseif (isset(self::$silencedErrorCache[$id][$message])) {
-                $lightTrace = null;
-                $errorAsException = self::$silencedErrorCache[$id][$message];
-                ++$errorAsException->count;
-            } else {
-                $lightTrace = [];
-                $errorAsException = null;
-            }
-
-            if (100 < ++self::$silencedErrorCount) {
-                self::$silencedErrorCache = $lightTrace = [];
-                self::$silencedErrorCount = 1;
-            }
-            if ($errorAsException) {
-                self::$silencedErrorCache[$id][$message] = $errorAsException;
-            }
-            if (null === $lightTrace) {
-                return true;
-            }
-        } else {
-            $errorAsException = new \ErrorException($logMessage, 0, $type, $file, $line);
-
-            if ($throw || $this->tracedErrors & $type) {
-                $backtrace = $errorAsException->getTrace();
-                $lightTrace = $this->cleanTrace($backtrace, $type, $file, $line, $throw);
-                $this->traceReflector->setValue($errorAsException, $lightTrace);
-            } else {
-                $this->traceReflector->setValue($errorAsException, []);
-                $backtrace = [];
-            }
-        }
-
-        if ($throw) {
-            if (E_USER_ERROR & $type) {
-                for ($i = 1; isset($backtrace[$i]); ++$i) {
-                    if (isset($backtrace[$i]['function'], $backtrace[$i]['type'], $backtrace[$i - 1]['function'])
-                        && '__toString' === $backtrace[$i]['function']
-                        && '->' === $backtrace[$i]['type']
-                        && !isset($backtrace[$i - 1]['class'])
-                        && ('trigger_error' === $backtrace[$i - 1]['function'] || 'user_error' === $backtrace[$i - 1]['function'])
-                    ) {
-                        // Here, we know trigger_error() has been called from __toString().
-                        // PHP triggers a fatal error when throwing from __toString().
-                        // A small convention allows working around the limitation:
-                        // given a caught $e exception in __toString(), quitting the method with
-                        // `return trigger_error($e, E_USER_ERROR);` allows this error handler
-                        // to make $e get through the __toString() barrier.
-
-                        foreach ($context as $e) {
-                            if ($e instanceof \Throwable && $e->__toString() === $message) {
-                                self::$toStringException = $e;
-
-                                return true;
-                            }
-                        }
-
-                        // Display the original error message instead of the default one.
-                        $this->handleException($errorAsException);
-
-                        // Stop the process by giving back the error to the native handler.
-                        return false;
-                    }
-                }
-            }
-
-            throw $errorAsException;
-        }
-
-        if ($this->isRecursive) {
-            $log = 0;
-        } else {
-            if (!\defined('HHVM_VERSION')) {
-                $currentErrorHandler = set_error_handler('var_dump');
-                restore_error_handler();
-            }
-
-            try {
-                $this->isRecursive = true;
-                $level = ($type & $level) ? $this->loggers[$type][1] : LogLevel::DEBUG;
-                $this->loggers[$type][0]->log($level, $logMessage, $errorAsException ? ['exception' => $errorAsException] : []);
-            } finally {
-                $this->isRecursive = false;
-
-                if (!\defined('HHVM_VERSION')) {
-                    set_error_handler($currentErrorHandler);
-                }
-            }
-        }
-
-        return !$silenced && $type && $log;
-    }
-
-    /**
-     * Handles an exception by logging then forwarding it to another handler.
-     *
-     * @param \Exception|\Throwable $exception An exception to handle
-     * @param array                 $error     An array as returned by error_get_last()
-     *
-     * @internal
-     */
-    public function handleException($exception, array $error = null)
-    {
-        if (null === $error) {
-            self::$exitCode = 255;
-        }
-        if (!$exception instanceof \Exception) {
-            $exception = new FatalThrowableError($exception);
-        }
-        $type = $exception instanceof FatalErrorException ? $exception->getSeverity() : E_ERROR;
-        $handlerException = null;
-
-        if (($this->loggedErrors & $type) || $exception instanceof FatalThrowableError) {
-            if (false !== strpos($message = $exception->getMessage(), "class@anonymous\0")) {
-                $message = (new FlattenException())->setMessage($message)->getMessage();
-            }
-            if ($exception instanceof FatalErrorException) {
-                if ($exception instanceof FatalThrowableError) {
-                    $error = [
-                        'type' => $type,
-                        'message' => $message,
-                        'file' => $exception->getFile(),
-                        'line' => $exception->getLine(),
-                    ];
-                } else {
-                    $message = 'Fatal '.$message;
-                }
-            } elseif ($exception instanceof \ErrorException) {
-                $message = 'Uncaught '.$message;
-            } else {
-                $message = 'Uncaught Exception: '.$message;
-            }
-        }
-        if ($this->loggedErrors & $type) {
-            try {
-                $this->loggers[$type][0]->log($this->loggers[$type][1], $message, ['exception' => $exception]);
-            } catch (\Throwable $handlerException) {
-            }
-        }
-        if ($exception instanceof FatalErrorException && !$exception instanceof OutOfMemoryException && $error) {
-            foreach ($this->getFatalErrorHandlers() as $handler) {
-                if ($e = $handler->handleError($error, $exception)) {
-                    $exception = $e;
-                    break;
-                }
-            }
-        }
-        $exceptionHandler = $this->exceptionHandler;
-        $this->exceptionHandler = null;
-        try {
-            if (null !== $exceptionHandler) {
-                return $exceptionHandler($exception);
-            }
-            $handlerException = $handlerException ?: $exception;
-        } catch (\Throwable $handlerException) {
-        }
-        if ($exception === $handlerException) {
-            self::$reservedMemory = null; // Disable the fatal error handler
-            throw $exception; // Give back $exception to the native handler
-        }
-        $this->handleException($handlerException);
-    }
-
-    /**
-     * Shutdown registered function for handling PHP fatal errors.
-     *
-     * @param array $error An array as returned by error_get_last()
-     *
-     * @internal
-     */
-    public static function handleFatalError(array $error = null)
-    {
-        if (null === self::$reservedMemory) {
-            return;
-        }
-
-        $handler = self::$reservedMemory = null;
-        $handlers = [];
-        $previousHandler = null;
-        $sameHandlerLimit = 10;
-
-        while (!\is_array($handler) || !$handler[0] instanceof self) {
-            $handler = set_exception_handler('var_dump');
-            restore_exception_handler();
-
-            if (!$handler) {
-                break;
-            }
-            restore_exception_handler();
-
-            if ($handler !== $previousHandler) {
-                array_unshift($handlers, $handler);
-                $previousHandler = $handler;
-            } elseif (0 === --$sameHandlerLimit) {
-                $handler = null;
-                break;
-            }
-        }
-        foreach ($handlers as $h) {
-            set_exception_handler($h);
-        }
-        if (!$handler) {
-            return;
-        }
-        if ($handler !== $h) {
-            $handler[0]->setExceptionHandler($h);
-        }
-        $handler = $handler[0];
-        $handlers = [];
-
-        if ($exit = null === $error) {
-            $error = error_get_last();
-        }
-
-        if ($error && $error['type'] &= E_PARSE | E_ERROR | E_CORE_ERROR | E_COMPILE_ERROR) {
-            // Let's not throw anymore but keep logging
-            $handler->throwAt(0, true);
-            $trace = isset($error['backtrace']) ? $error['backtrace'] : null;
-
-            if (0 === strpos($error['message'], 'Allowed memory') || 0 === strpos($error['message'], 'Out of memory')) {
-                $exception = new OutOfMemoryException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, false, $trace);
-            } else {
-                $exception = new FatalErrorException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, true, $trace);
-            }
-        } else {
-            $exception = null;
-        }
-
-        try {
-            if (null !== $exception) {
-                self::$exitCode = 255;
-                $handler->handleException($exception, $error);
-            }
-        } catch (FatalErrorException $e) {
-            // Ignore this re-throw
-        }
-
-        if ($exit && self::$exitCode) {
-            $exitCode = self::$exitCode;
-            register_shutdown_function('register_shutdown_function', function () use ($exitCode) { exit($exitCode); });
-        }
-    }
-
-    /**
-     * Gets the fatal error handlers.
-     *
-     * Override this method if you want to define more fatal error handlers.
-     *
-     * @return FatalErrorHandlerInterface[] An array of FatalErrorHandlerInterface
-     */
-    protected function getFatalErrorHandlers()
-    {
-        return [
-            new UndefinedFunctionFatalErrorHandler(),
-            new UndefinedMethodFatalErrorHandler(),
-            new ClassNotFoundFatalErrorHandler(),
-        ];
-    }
-
-    /**
-     * Cleans the trace by removing function arguments and the frames added by the error handler and DebugClassLoader.
-     */
-    private function cleanTrace($backtrace, $type, $file, $line, $throw)
-    {
-        $lightTrace = $backtrace;
-
-        for ($i = 0; isset($backtrace[$i]); ++$i) {
-            if (isset($backtrace[$i]['file'], $backtrace[$i]['line']) && $backtrace[$i]['line'] === $line && $backtrace[$i]['file'] === $file) {
-                $lightTrace = \array_slice($lightTrace, 1 + $i);
-                break;
-            }
-        }
-        if (class_exists(DebugClassLoader::class, false)) {
-            for ($i = \count($lightTrace) - 2; 0 < $i; --$i) {
-                if (DebugClassLoader::class === ($lightTrace[$i]['class'] ?? null)) {
-                    array_splice($lightTrace, --$i, 2);
-                }
-            }
-        }
-        if (!($throw || $this->scopedErrors & $type)) {
-            for ($i = 0; isset($lightTrace[$i]); ++$i) {
-                unset($lightTrace[$i]['args'], $lightTrace[$i]['object']);
-            }
-        }
-
-        return $lightTrace;
-    }
 }

src/Symfony/Component/Debug/Exception/ClassNotFoundException.php

@@ -11,26 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\ClassNotFoundException as BaseClassNotFoundException;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', ClassNotFoundException::class, BaseClassNotFoundException::class), E_USER_DEPRECATED);
+
 /**
- * Class (or Trait or Interface) Not Found Exception.
- *
- * @author Konstanton Myakshin <koc-dp@yandex.ru>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\ClassNotFoundException instead.
  */
-class ClassNotFoundException extends FatalErrorException
+class ClassNotFoundException extends BaseClassNotFoundException
 {
-    public function __construct(string $message, \ErrorException $previous)
-    {
-        parent::__construct(
-            $message,
-            $previous->getCode(),
-            $previous->getSeverity(),
-            $previous->getFile(),
-            $previous->getLine(),
-            null,
-            true,
-            null,
-            $previous->getPrevious()
-        );
-        $this->setTrace($previous->getTrace());
-    }
 }

src/Symfony/Component/Debug/Exception/FatalErrorException.php

@@ -11,67 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException as BaseFatalErrorException;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', FatalErrorException::class, BaseFatalErrorException::class), E_USER_DEPRECATED);
+
 /**
- * Fatal Error Exception.
- *
- * @author Konstanton Myakshin <koc-dp@yandex.ru>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\FatalErrorException instead.
  */
-class FatalErrorException extends \ErrorException
+class FatalErrorException extends BaseFatalErrorException
 {
-    public function __construct(string $message, int $code, int $severity, string $filename, int $lineno, int $traceOffset = null, bool $traceArgs = true, array $trace = null, \Throwable $previous = null)
-    {
-        parent::__construct($message, $code, $severity, $filename, $lineno, $previous);
-
-        if (null !== $trace) {
-            if (!$traceArgs) {
-                foreach ($trace as &$frame) {
-                    unset($frame['args'], $frame['this'], $frame);
-                }
-            }
-
-            $this->setTrace($trace);
-        } elseif (null !== $traceOffset) {
-            if (\function_exists('xdebug_get_function_stack')) {
-                $trace = xdebug_get_function_stack();
-                if (0 < $traceOffset) {
-                    array_splice($trace, -$traceOffset);
-                }
-
-                foreach ($trace as &$frame) {
-                    if (!isset($frame['type'])) {
-                        // XDebug pre 2.1.1 doesn't currently set the call type key http://bugs.xdebug.org/view.php?id=695
-                        if (isset($frame['class'])) {
-                            $frame['type'] = '::';
-                        }
-                    } elseif ('dynamic' === $frame['type']) {
-                        $frame['type'] = '->';
-                    } elseif ('static' === $frame['type']) {
-                        $frame['type'] = '::';
-                    }
-
-                    // XDebug also has a different name for the parameters array
-                    if (!$traceArgs) {
-                        unset($frame['params'], $frame['args']);
-                    } elseif (isset($frame['params']) && !isset($frame['args'])) {
-                        $frame['args'] = $frame['params'];
-                        unset($frame['params']);
-                    }
-                }
-
-                unset($frame);
-                $trace = array_reverse($trace);
-            } else {
-                $trace = [];
-            }
-
-            $this->setTrace($trace);
-        }
-    }
-
-    protected function setTrace($trace)
-    {
-        $traceReflector = new \ReflectionProperty('Exception', 'trace');
-        $traceReflector->setAccessible(true);
-        $traceReflector->setValue($this, $trace);
-    }
 }

src/Symfony/Component/Debug/Exception/FatalThrowableError.php

@@ -11,41 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\FatalThrowableError as BaseFatalThrowableError;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', FatalThrowableError::class, BaseFatalThrowableError::class), E_USER_DEPRECATED);
+
 /**
- * Fatal Throwable Error.
- *
- * @author Nicolas Grekas <p@tchwork.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\FatalThrowableError instead.
  */
-class FatalThrowableError extends FatalErrorException
+class FatalThrowableError extends BaseFatalThrowableError
 {
-    private $originalClassName;
-
-    public function __construct(\Throwable $e)
-    {
-        $this->originalClassName = \get_class($e);
-
-        if ($e instanceof \ParseError) {
-            $severity = E_PARSE;
-        } elseif ($e instanceof \TypeError) {
-            $severity = E_RECOVERABLE_ERROR;
-        } else {
-            $severity = E_ERROR;
-        }
-
-        \ErrorException::__construct(
-            $e->getMessage(),
-            $e->getCode(),
-            $severity,
-            $e->getFile(),
-            $e->getLine(),
-            $e->getPrevious()
-        );
-
-        $this->setTrace($e->getTrace());
-    }
-
-    public function getOriginalClassName(): string
-    {
-        return $this->originalClassName;
-    }
 }

src/Symfony/Component/Debug/Exception/FlattenException.php

@@ -11,349 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
-use Symfony\Component\HttpFoundation\Exception\RequestExceptionInterface;
-use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
+use Symfony\Component\ErrorHandler\Exception\FlattenException as BaseFlattenException;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', FlattenException::class, BaseFlattenException::class), E_USER_DEPRECATED);
 
 /**
- * FlattenException wraps a PHP Error or Exception to be able to serialize it.
- *
- * Basically, this class removes all objects from the trace.
- *
- * @author Fabien Potencier <fabien@symfony.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\FlattenException instead.
  */
-class FlattenException
+class FlattenException extends BaseFlattenException
 {
-    private $message;
-    private $code;
-    private $previous;
-    private $trace;
-    private $traceAsString;
-    private $class;
-    private $statusCode;
-    private $headers;
-    private $file;
-    private $line;
-
-    public static function create(\Exception $exception, $statusCode = null, array $headers = [])
-    {
-        return static::createFromThrowable($exception, $statusCode, $headers);
-    }
-
-    public static function createFromThrowable(\Throwable $exception, ?int $statusCode = null, array $headers = []): self
-    {
-        $e = new static();
-        $e->setMessage($exception->getMessage());
-        $e->setCode($exception->getCode());
-
-        if ($exception instanceof HttpExceptionInterface) {
-            $statusCode = $exception->getStatusCode();
-            $headers = array_merge($headers, $exception->getHeaders());
-        } elseif ($exception instanceof RequestExceptionInterface) {
-            $statusCode = 400;
-        }
-
-        if (null === $statusCode) {
-            $statusCode = 500;
-        }
-
-        $e->setStatusCode($statusCode);
-        $e->setHeaders($headers);
-        $e->setTraceFromThrowable($exception);
-        $e->setClass($exception instanceof FatalThrowableError ? $exception->getOriginalClassName() : \get_class($exception));
-        $e->setFile($exception->getFile());
-        $e->setLine($exception->getLine());
-
-        $previous = $exception->getPrevious();
-
-        if ($previous instanceof \Throwable) {
-            $e->setPrevious(static::createFromThrowable($previous));
-        }
-
-        return $e;
-    }
-
-    public function toArray()
-    {
-        $exceptions = [];
-        foreach (array_merge([$this], $this->getAllPrevious()) as $exception) {
-            $exceptions[] = [
-                'message' => $exception->getMessage(),
-                'class' => $exception->getClass(),
-                'trace' => $exception->getTrace(),
-            ];
-        }
-
-        return $exceptions;
-    }
-
-    public function getStatusCode()
-    {
-        return $this->statusCode;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setStatusCode($code)
-    {
-        $this->statusCode = $code;
-
-        return $this;
-    }
-
-    public function getHeaders()
-    {
-        return $this->headers;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setHeaders(array $headers)
-    {
-        $this->headers = $headers;
-
-        return $this;
-    }
-
-    public function getClass()
-    {
-        return $this->class;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setClass($class)
-    {
-        $this->class = 'c' === $class[0] && 0 === strpos($class, "class@anonymous\0") ? get_parent_class($class).'@anonymous' : $class;
-
-        return $this;
-    }
-
-    public function getFile()
-    {
-        return $this->file;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setFile($file)
-    {
-        $this->file = $file;
-
-        return $this;
-    }
-
-    public function getLine()
-    {
-        return $this->line;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setLine($line)
-    {
-        $this->line = $line;
-
-        return $this;
-    }
-
-    public function getMessage()
-    {
-        return $this->message;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setMessage($message)
-    {
-        if (false !== strpos($message, "class@anonymous\0")) {
-            $message = preg_replace_callback('/class@anonymous\x00.*?\.php0x?[0-9a-fA-F]++/', function ($m) {
-                return class_exists($m[0], false) ? get_parent_class($m[0]).'@anonymous' : $m[0];
-            }, $message);
-        }
-
-        $this->message = $message;
-
-        return $this;
-    }
-
-    public function getCode()
-    {
-        return $this->code;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setCode($code)
-    {
-        $this->code = $code;
-
-        return $this;
-    }
-
-    public function getPrevious()
-    {
-        return $this->previous;
-    }
-
-    /**
-     * @return $this
-     */
-    public function setPrevious(self $previous)
-    {
-        $this->previous = $previous;
-
-        return $this;
-    }
-
-    public function getAllPrevious()
-    {
-        $exceptions = [];
-        $e = $this;
-        while ($e = $e->getPrevious()) {
-            $exceptions[] = $e;
-        }
-
-        return $exceptions;
-    }
-
-    public function getTrace()
-    {
-        return $this->trace;
-    }
-
-    /**
-     * @deprecated since 4.1, use {@see setTraceFromThrowable()} instead.
-     */
-    public function setTraceFromException(\Exception $exception)
-    {
-        @trigger_error(sprintf('The "%s()" method is deprecated since Symfony 4.1, use "setTraceFromThrowable()" instead.', __METHOD__), E_USER_DEPRECATED);
-
-        $this->setTraceFromThrowable($exception);
-    }
-
-    public function setTraceFromThrowable(\Throwable $throwable)
-    {
-        $this->traceAsString = $throwable->getTraceAsString();
-
-        return $this->setTrace($throwable->getTrace(), $throwable->getFile(), $throwable->getLine());
-    }
-
-    /**
-     * @return $this
-     */
-    public function setTrace($trace, $file, $line)
-    {
-        $this->trace = [];
-        $this->trace[] = [
-            'namespace' => '',
-            'short_class' => '',
-            'class' => '',
-            'type' => '',
-            'function' => '',
-            'file' => $file,
-            'line' => $line,
-            'args' => [],
-        ];
-        foreach ($trace as $entry) {
-            $class = '';
-            $namespace = '';
-            if (isset($entry['class'])) {
-                $parts = explode('\\', $entry['class']);
-                $class = array_pop($parts);
-                $namespace = implode('\\', $parts);
-            }
-
-            $this->trace[] = [
-                'namespace' => $namespace,
-                'short_class' => $class,
-                'class' => isset($entry['class']) ? $entry['class'] : '',
-                'type' => isset($entry['type']) ? $entry['type'] : '',
-                'function' => isset($entry['function']) ? $entry['function'] : null,
-                'file' => isset($entry['file']) ? $entry['file'] : null,
-                'line' => isset($entry['line']) ? $entry['line'] : null,
-                'args' => isset($entry['args']) ? $this->flattenArgs($entry['args']) : [],
-            ];
-        }
-
-        return $this;
-    }
-
-    private function flattenArgs($args, $level = 0, &$count = 0)
-    {
-        $result = [];
-        foreach ($args as $key => $value) {
-            if (++$count > 1e4) {
-                return ['array', '*SKIPPED over 10000 entries*'];
-            }
-            if ($value instanceof \__PHP_Incomplete_Class) {
-                // is_object() returns false on PHP<=7.1
-                $result[$key] = ['incomplete-object', $this->getClassNameFromIncomplete($value)];
-            } elseif (\is_object($value)) {
-                $result[$key] = ['object', \get_class($value)];
-            } elseif (\is_array($value)) {
-                if ($level > 10) {
-                    $result[$key] = ['array', '*DEEP NESTED ARRAY*'];
-                } else {
-                    $result[$key] = ['array', $this->flattenArgs($value, $level + 1, $count)];
-                }
-            } elseif (null === $value) {
-                $result[$key] = ['null', null];
-            } elseif (\is_bool($value)) {
-                $result[$key] = ['boolean', $value];
-            } elseif (\is_int($value)) {
-                $result[$key] = ['integer', $value];
-            } elseif (\is_float($value)) {
-                $result[$key] = ['float', $value];
-            } elseif (\is_resource($value)) {
-                $result[$key] = ['resource', get_resource_type($value)];
-            } else {
-                $result[$key] = ['string', (string) $value];
-            }
-        }
-
-        return $result;
-    }
-
-    private function getClassNameFromIncomplete(\__PHP_Incomplete_Class $value)
-    {
-        $array = new \ArrayObject($value);
-
-        return $array['__PHP_Incomplete_Class_Name'];
-    }
-
-    public function getTraceAsString()
-    {
-        return $this->traceAsString;
-    }
-
-    public function getAsString()
-    {
-        $message = '';
-        $next = false;
-
-        foreach (array_reverse(array_merge([$this], $this->getAllPrevious())) as $exception) {
-            if ($next) {
-                $message .= 'Next ';
-            } else {
-                $next = true;
-            }
-            $message .= $exception->getClass();
-
-            if ('' != $exception->getMessage()) {
-                $message .= ': '.$exception->getMessage();
-            }
-
-            $message .= ' in '.$exception->getFile().':'.$exception->getLine().
-                "\nStack trace:\n".$exception->getTraceAsString()."\n\n";
-        }
-
-        return rtrim($message);
-    }
 }

src/Symfony/Component/Debug/Exception/OutOfMemoryException.php

@@ -11,11 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\OutOfMemoryException as BaseOutOfMemoryException;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', OutOfMemoryException::class, BaseOutOfMemoryException::class), E_USER_DEPRECATED);
+
 /**
- * Out of memory exception.
- *
- * @author Nicolas Grekas <p@tchwork.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\OutOfMemoryException instead.
  */
-class OutOfMemoryException extends FatalErrorException
+class OutOfMemoryException extends BaseOutOfMemoryException
 {
 }

src/Symfony/Component/Debug/Exception/SilencedErrorContext.php

@@ -11,57 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\SilencedErrorContext as BaseSilencedErrorContext;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', SilencedErrorContext::class, BaseSilencedErrorContext::class), E_USER_DEPRECATED);
+
 /**
- * Data Object that represents a Silenced Error.
- *
- * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\SilencedErrorContext instead.
  */
-class SilencedErrorContext implements \JsonSerializable
+class SilencedErrorContext extends BaseSilencedErrorContext
 {
-    public $count = 1;
-
-    private $severity;
-    private $file;
-    private $line;
-    private $trace;
-
-    public function __construct(int $severity, string $file, int $line, array $trace = [], int $count = 1)
-    {
-        $this->severity = $severity;
-        $this->file = $file;
-        $this->line = $line;
-        $this->trace = $trace;
-        $this->count = $count;
-    }
-
-    public function getSeverity()
-    {
-        return $this->severity;
-    }
-
-    public function getFile()
-    {
-        return $this->file;
-    }
-
-    public function getLine()
-    {
-        return $this->line;
-    }
-
-    public function getTrace()
-    {
-        return $this->trace;
-    }
-
-    public function JsonSerialize()
-    {
-        return [
-            'severity' => $this->severity,
-            'file' => $this->file,
-            'line' => $this->line,
-            'trace' => $this->trace,
-            'count' => $this->count,
-        ];
-    }
 }

src/Symfony/Component/Debug/Exception/UndefinedFunctionException.php

@@ -11,26 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\UndefinedFunctionException as BaseUndefinedFunctionException;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', UndefinedFunctionException::class, BaseUndefinedFunctionException::class), E_USER_DEPRECATED);
+
 /**
- * Undefined Function Exception.
- *
- * @author Konstanton Myakshin <koc-dp@yandex.ru>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\UndefinedFunctionException instead.
  */
-class UndefinedFunctionException extends FatalErrorException
+class UndefinedFunctionException extends BaseUndefinedFunctionException
 {
-    public function __construct(string $message, \ErrorException $previous)
-    {
-        parent::__construct(
-            $message,
-            $previous->getCode(),
-            $previous->getSeverity(),
-            $previous->getFile(),
-            $previous->getLine(),
-            null,
-            true,
-            null,
-            $previous->getPrevious()
-        );
-        $this->setTrace($previous->getTrace());
-    }
 }

src/Symfony/Component/Debug/Exception/UndefinedMethodException.php

@@ -11,26 +11,13 @@
 
 namespace Symfony\Component\Debug\Exception;
 
+use Symfony\Component\ErrorHandler\Exception\UndefinedMethodException as BaseUndefinedMethodException;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', UndefinedMethodException::class, BaseUndefinedMethodException::class), E_USER_DEPRECATED);
+
 /**
- * Undefined Method Exception.
- *
- * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\Exception\UndefinedMethodException instead.
  */
-class UndefinedMethodException extends FatalErrorException
+class UndefinedMethodException extends BaseUndefinedMethodException
 {
-    public function __construct(string $message, \ErrorException $previous)
-    {
-        parent::__construct(
-            $message,
-            $previous->getCode(),
-            $previous->getSeverity(),
-            $previous->getFile(),
-            $previous->getLine(),
-            null,
-            true,
-            null,
-            $previous->getPrevious()
-        );
-        $this->setTrace($previous->getTrace());
-    }
 }

src/Symfony/Component/Debug/FatalErrorHandler/ClassNotFoundFatalErrorHandler.php

@@ -11,183 +11,13 @@
 
 namespace Symfony\Component\Debug\FatalErrorHandler;
 
-use Composer\Autoload\ClassLoader as ComposerClassLoader;
-use Symfony\Component\ClassLoader\ClassLoader as SymfonyClassLoader;
-use Symfony\Component\Debug\DebugClassLoader;
-use Symfony\Component\Debug\Exception\ClassNotFoundException;
-use Symfony\Component\Debug\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\ClassNotFoundFatalErrorHandler as BaseClassNotFoundFatalErrorHandler;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', ClassNotFoundFatalErrorHandler::class, BaseClassNotFoundFatalErrorHandler::class), E_USER_DEPRECATED);
 
 /**
- * ErrorHandler for classes that do not exist.
- *
- * @author Fabien Potencier <fabien@symfony.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\FatalErrorHandler\ClassNotFoundFatalErrorHandler instead.
  */
-class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
+class ClassNotFoundFatalErrorHandler extends BaseClassNotFoundFatalErrorHandler
 {
-    /**
-     * {@inheritdoc}
-     */
-    public function handleError(array $error, FatalErrorException $exception)
-    {
-        $messageLen = \strlen($error['message']);
-        $notFoundSuffix = '\' not found';
-        $notFoundSuffixLen = \strlen($notFoundSuffix);
-        if ($notFoundSuffixLen > $messageLen) {
-            return;
-        }
-
-        if (0 !== substr_compare($error['message'], $notFoundSuffix, -$notFoundSuffixLen)) {
-            return;
-        }
-
-        foreach (['class', 'interface', 'trait'] as $typeName) {
-            $prefix = ucfirst($typeName).' \'';
-            $prefixLen = \strlen($prefix);
-            if (0 !== strpos($error['message'], $prefix)) {
-                continue;
-            }
-
-            $fullyQualifiedClassName = substr($error['message'], $prefixLen, -$notFoundSuffixLen);
-            if (false !== $namespaceSeparatorIndex = strrpos($fullyQualifiedClassName, '\\')) {
-                $className = substr($fullyQualifiedClassName, $namespaceSeparatorIndex + 1);
-                $namespacePrefix = substr($fullyQualifiedClassName, 0, $namespaceSeparatorIndex);
-                $message = sprintf('Attempted to load %s "%s" from namespace "%s".', $typeName, $className, $namespacePrefix);
-                $tail = ' for another namespace?';
-            } else {
-                $className = $fullyQualifiedClassName;
-                $message = sprintf('Attempted to load %s "%s" from the global namespace.', $typeName, $className);
-                $tail = '?';
-            }
-
-            if ($candidates = $this->getClassCandidates($className)) {
-                $tail = array_pop($candidates).'"?';
-                if ($candidates) {
-                    $tail = ' for e.g. "'.implode('", "', $candidates).'" or "'.$tail;
-                } else {
-                    $tail = ' for "'.$tail;
-                }
-            }
-            $message .= "\nDid you forget a \"use\" statement".$tail;
-
-            return new ClassNotFoundException($message, $exception);
-        }
-    }
-
-    /**
-     * Tries to guess the full namespace for a given class name.
-     *
-     * By default, it looks for PSR-0 and PSR-4 classes registered via a Symfony or a Composer
-     * autoloader (that should cover all common cases).
-     *
-     * @param string $class A class name (without its namespace)
-     *
-     * @return array An array of possible fully qualified class names
-     */
-    private function getClassCandidates(string $class): array
-    {
-        if (!\is_array($functions = spl_autoload_functions())) {
-            return [];
-        }
-
-        // find Symfony and Composer autoloaders
-        $classes = [];
-
-        foreach ($functions as $function) {
-            if (!\is_array($function)) {
-                continue;
-            }
-            // get class loaders wrapped by DebugClassLoader
-            if ($function[0] instanceof DebugClassLoader) {
-                $function = $function[0]->getClassLoader();
-
-                if (!\is_array($function)) {
-                    continue;
-                }
-            }
-
-            if ($function[0] instanceof ComposerClassLoader || $function[0] instanceof SymfonyClassLoader) {
-                foreach ($function[0]->getPrefixes() as $prefix => $paths) {
-                    foreach ($paths as $path) {
-                        $classes = array_merge($classes, $this->findClassInPath($path, $class, $prefix));
-                    }
-                }
-            }
-            if ($function[0] instanceof ComposerClassLoader) {
-                foreach ($function[0]->getPrefixesPsr4() as $prefix => $paths) {
-                    foreach ($paths as $path) {
-                        $classes = array_merge($classes, $this->findClassInPath($path, $class, $prefix));
-                    }
-                }
-            }
-        }
-
-        return array_unique($classes);
-    }
-
-    private function findClassInPath(string $path, string $class, string $prefix): array
-    {
-        if (!$path = realpath($path.'/'.strtr($prefix, '\\_', '//')) ?: realpath($path.'/'.\dirname(strtr($prefix, '\\_', '//'))) ?: realpath($path)) {
-            return [];
-        }
-
-        $classes = [];
-        $filename = $class.'.php';
-        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($path, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::LEAVES_ONLY) as $file) {
-            if ($filename == $file->getFileName() && $class = $this->convertFileToClass($path, $file->getPathName(), $prefix)) {
-                $classes[] = $class;
-            }
-        }
-
-        return $classes;
-    }
-
-    private function convertFileToClass(string $path, string $file, string $prefix): ?string
-    {
-        $candidates = [
-            // namespaced class
-            $namespacedClass = str_replace([$path.\DIRECTORY_SEPARATOR, '.php', '/'], ['', '', '\\'], $file),
-            // namespaced class (with target dir)
-            $prefix.$namespacedClass,
-            // namespaced class (with target dir and separator)
-            $prefix.'\\'.$namespacedClass,
-            // PEAR class
-            str_replace('\\', '_', $namespacedClass),
-            // PEAR class (with target dir)
-            str_replace('\\', '_', $prefix.$namespacedClass),
-            // PEAR class (with target dir and separator)
-            str_replace('\\', '_', $prefix.'\\'.$namespacedClass),
-        ];
-
-        if ($prefix) {
-            $candidates = array_filter($candidates, function ($candidate) use ($prefix) { return 0 === strpos($candidate, $prefix); });
-        }
-
-        // We cannot use the autoloader here as most of them use require; but if the class
-        // is not found, the new autoloader call will require the file again leading to a
-        // "cannot redeclare class" error.
-        foreach ($candidates as $candidate) {
-            if ($this->classExists($candidate)) {
-                return $candidate;
-            }
-        }
-
-        try {
-            require_once $file;
-        } catch (\Throwable $e) {
-            return null;
-        }
-
-        foreach ($candidates as $candidate) {
-            if ($this->classExists($candidate)) {
-                return $candidate;
-            }
-        }
-
-        return null;
-    }
-
-    private function classExists(string $class): bool
-    {
-        return class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false);
-    }
 }

src/Symfony/Component/Debug/FatalErrorHandler/FatalErrorHandlerInterface.php

@@ -11,22 +11,13 @@
 
 namespace Symfony\Component\Debug\FatalErrorHandler;
 
-use Symfony\Component\Debug\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\FatalErrorHandlerInterface as BaseFatalErrorHandlerInterface;
+
+@trigger_error(sprintf('The "%s" interface is deprecated since Symfony 4.4, use "%s" instead.', FatalErrorHandlerInterface::class, BaseFatalErrorHandlerInterface::class), E_USER_DEPRECATED);
 
 /**
- * Attempts to convert fatal errors to exceptions.
- *
- * @author Fabien Potencier <fabien@symfony.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\FatalErrorHandler\FatalErrorHandlerInterface instead.
  */
-interface FatalErrorHandlerInterface
+interface FatalErrorHandlerInterface extends BaseFatalErrorHandlerInterface
 {
-    /**
-     * Attempts to convert an error into an exception.
-     *
-     * @param array               $error     An array as returned by error_get_last()
-     * @param FatalErrorException $exception A FatalErrorException instance
-     *
-     * @return FatalErrorException|null A FatalErrorException instance if the class is able to convert the error, null otherwise
-     */
-    public function handleError(array $error, FatalErrorException $exception);
 }

src/Symfony/Component/Debug/FatalErrorHandler/UndefinedFunctionFatalErrorHandler.php

@@ -11,74 +11,13 @@
 
 namespace Symfony\Component\Debug\FatalErrorHandler;
 
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\Exception\UndefinedFunctionException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedFunctionFatalErrorHandler as BaseUndefinedFunctionFatalErrorHandler;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', UndefinedFunctionFatalErrorHandler::class, BaseUndefinedFunctionFatalErrorHandler::class), E_USER_DEPRECATED);
 
 /**
- * ErrorHandler for undefined functions.
- *
- * @author Fabien Potencier <fabien@symfony.com>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedFunctionFatalErrorHandler instead.
  */
-class UndefinedFunctionFatalErrorHandler implements FatalErrorHandlerInterface
+class UndefinedFunctionFatalErrorHandler extends BaseUndefinedFunctionFatalErrorHandler
 {
-    /**
-     * {@inheritdoc}
-     */
-    public function handleError(array $error, FatalErrorException $exception)
-    {
-        $messageLen = \strlen($error['message']);
-        $notFoundSuffix = '()';
-        $notFoundSuffixLen = \strlen($notFoundSuffix);
-        if ($notFoundSuffixLen > $messageLen) {
-            return;
-        }
-
-        if (0 !== substr_compare($error['message'], $notFoundSuffix, -$notFoundSuffixLen)) {
-            return;
-        }
-
-        $prefix = 'Call to undefined function ';
-        $prefixLen = \strlen($prefix);
-        if (0 !== strpos($error['message'], $prefix)) {
-            return;
-        }
-
-        $fullyQualifiedFunctionName = substr($error['message'], $prefixLen, -$notFoundSuffixLen);
-        if (false !== $namespaceSeparatorIndex = strrpos($fullyQualifiedFunctionName, '\\')) {
-            $functionName = substr($fullyQualifiedFunctionName, $namespaceSeparatorIndex + 1);
-            $namespacePrefix = substr($fullyQualifiedFunctionName, 0, $namespaceSeparatorIndex);
-            $message = sprintf('Attempted to call function "%s" from namespace "%s".', $functionName, $namespacePrefix);
-        } else {
-            $functionName = $fullyQualifiedFunctionName;
-            $message = sprintf('Attempted to call function "%s" from the global namespace.', $functionName);
-        }
-
-        $candidates = [];
-        foreach (get_defined_functions() as $type => $definedFunctionNames) {
-            foreach ($definedFunctionNames as $definedFunctionName) {
-                if (false !== $namespaceSeparatorIndex = strrpos($definedFunctionName, '\\')) {
-                    $definedFunctionNameBasename = substr($definedFunctionName, $namespaceSeparatorIndex + 1);
-                } else {
-                    $definedFunctionNameBasename = $definedFunctionName;
-                }
-
-                if ($definedFunctionNameBasename === $functionName) {
-                    $candidates[] = '\\'.$definedFunctionName;
-                }
-            }
-        }
-
-        if ($candidates) {
-            sort($candidates);
-            $last = array_pop($candidates).'"?';
-            if ($candidates) {
-                $candidates = 'e.g. "'.implode('", "', $candidates).'" or "'.$last;
-            } else {
-                $candidates = '"'.$last;
-            }
-            $message .= "\nDid you mean to call ".$candidates;
-        }
-
-        return new UndefinedFunctionException($message, $exception);
-    }
 }

src/Symfony/Component/Debug/FatalErrorHandler/UndefinedMethodFatalErrorHandler.php

@@ -11,56 +11,13 @@
 
 namespace Symfony\Component\Debug\FatalErrorHandler;
 
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\Exception\UndefinedMethodException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedMethodFatalErrorHandler as BaseUndefinedMethodFatalErrorHandler;
+
+@trigger_error(sprintf('The "%s" class is deprecated since Symfony 4.4, use "%s" instead.', UndefinedMethodFatalErrorHandler::class, BaseUndefinedMethodFatalErrorHandler::class), E_USER_DEPRECATED);
 
 /**
- * ErrorHandler for undefined methods.
- *
- * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ * @deprecated since Symfony 4.4, use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedMethodFatalErrorHandler instead.
  */
-class UndefinedMethodFatalErrorHandler implements FatalErrorHandlerInterface
+class UndefinedMethodFatalErrorHandler extends BaseUndefinedMethodFatalErrorHandler
 {
-    /**
-     * {@inheritdoc}
-     */
-    public function handleError(array $error, FatalErrorException $exception)
-    {
-        preg_match('/^Call to undefined method (.*)::(.*)\(\)$/', $error['message'], $matches);
-        if (!$matches) {
-            return;
-        }
-
-        $className = $matches[1];
-        $methodName = $matches[2];
-
-        $message = sprintf('Attempted to call an undefined method named "%s" of class "%s".', $methodName, $className);
-
-        if (!class_exists($className) || null === $methods = get_class_methods($className)) {
-            // failed to get the class or its methods on which an unknown method was called (for example on an anonymous class)
-            return new UndefinedMethodException($message, $exception);
-        }
-
-        $candidates = [];
-        foreach ($methods as $definedMethodName) {
-            $lev = levenshtein($methodName, $definedMethodName);
-            if ($lev <= \strlen($methodName) / 3 || false !== strpos($definedMethodName, $methodName)) {
-                $candidates[] = $definedMethodName;
-            }
-        }
-
-        if ($candidates) {
-            sort($candidates);
-            $last = array_pop($candidates).'"?';
-            if ($candidates) {
-                $candidates = 'e.g. "'.implode('", "', $candidates).'" or "'.$last;
-            } else {
-                $candidates = '"'.$last;
-            }
-
-            $message .= "\nDid you mean to call ".$candidates;
-        }
-
-        return new UndefinedMethodException($message, $exception);
-    }
 }

src/Symfony/Component/Debug/Tests/Fixtures/PEARClass.php

@@ -1,5 +0,0 @@
-<?php
-
-class Symfony_Component_Debug_Tests_Fixtures_PEARClass
-{
-}

src/Symfony/Component/Debug/composer.json

@@ -17,7 +17,8 @@
     ],
     "require": {
         "php": "^7.1.3",
-        "psr/log": "~1.0"
+        "psr/log": "~1.0",
+        "symfony/error-handler": "^4.4"
     },
     "conflict": {
         "symfony/http-kernel": "<3.4"

src/Symfony/Component/ErrorHandler/.gitignore

@@ -0,0 +1,3 @@
+vendor/
+composer.lock
+phpunit.xml

src/Symfony/Component/ErrorHandler/BufferingLogger.php

@@ -0,0 +1,37 @@
+<?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\ErrorHandler;
+
+use Psr\Log\AbstractLogger;
+
+/**
+ * A buffering logger that stacks logs for later.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class BufferingLogger extends AbstractLogger
+{
+    private $logs = [];
+
+    public function log($level, $message, array $context = [])
+    {
+        $this->logs[] = [$level, $message, $context];
+    }
+
+    public function cleanLogs()
+    {
+        $logs = $this->logs;
+        $this->logs = [];
+
+        return $logs;
+    }
+}

src/Symfony/Component/ErrorHandler/CHANGELOG.md

@@ -0,0 +1,7 @@
+CHANGELOG
+=========
+
+4.4.0
+-----
+
+ * added the component

src/Symfony/Component/ErrorHandler/DependencyInjection/ErrorHandlerPass.php

@@ -0,0 +1,66 @@
+<?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\ErrorHandler\DependencyInjection;
+
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\ServiceLocatorTagPass;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRendererInterface;
+
+/**
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+class ErrorHandlerPass implements CompilerPassInterface
+{
+    private $rendererService;
+    private $rendererTag;
+
+    public function __construct(string $rendererService = 'error_handler.error_renderer', string $rendererTag = 'error_handler.renderer')
+    {
+        $this->rendererService = $rendererService;
+        $this->rendererTag = $rendererTag;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function process(ContainerBuilder $container)
+    {
+        if (!$container->hasDefinition($this->rendererService)) {
+            return;
+        }
+
+        $renderers = $registered = [];
+        foreach ($container->findTaggedServiceIds($this->rendererTag, true) as $serviceId => $tags) {
+            /** @var ErrorRendererInterface $class */
+            $class = $container->getDefinition($serviceId)->getClass();
+
+            foreach ($tags as $tag) {
+                $format = $tag['format'] ?? $class::getFormat();
+                if (!isset($registered[$format])) {
+                    $priority = $tag['priority'] ?? 0;
+                    $renderers[$priority][$format] = new Reference($serviceId);
+                    $registered[$format] = true;
+                }
+            }
+        }
+
+        if ($renderers) {
+            krsort($renderers);
+            $renderers = array_merge(...$renderers);
+        }
+
+        $definition = $container->getDefinition($this->rendererService);
+        $definition->replaceArgument(0, ServiceLocatorTagPass::register($container, $renderers));
+    }
+}

src/Symfony/Component/ErrorHandler/DependencyInjection/ErrorRenderer.php

@@ -0,0 +1,44 @@
+<?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\ErrorHandler\DependencyInjection;
+
+use Psr\Container\ContainerInterface;
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRenderer as BaseErrorRenderer;
+
+/**
+ * Lazily loads error renderers from the dependency injection container.
+ *
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+class ErrorRenderer extends BaseErrorRenderer
+{
+    private $container;
+    private $initialized = [];
+
+    public function __construct(ContainerInterface $container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function render($exception, string $format = 'html'): string
+    {
+        if (!isset($this->initialized[$format]) && $this->container->has($format)) {
+            $this->addRenderer($this->container->get($format), $format);
+            $this->initialized[$format] = true;
+        }
+
+        return parent::render($exception, $format);
+    }
+}

src/Symfony/Component/ErrorHandler/ErrorHandler.php

@@ -0,0 +1,711 @@
+<?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\ErrorHandler;
+
+use Psr\Log\LoggerInterface;
+use Psr\Log\LogLevel;
+use Symfony\Component\Debug\DebugClassLoader;
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\Exception\FatalThrowableError;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\OutOfMemoryException;
+use Symfony\Component\ErrorHandler\Exception\SilencedErrorContext;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\FatalErrorHandlerInterface;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedMethodFatalErrorHandler;
+
+/**
+ * A generic ErrorHandler for the PHP engine.
+ *
+ * Provides five bit fields that control how errors are handled:
+ * - thrownErrors: errors thrown as \ErrorException
+ * - loggedErrors: logged errors, when not @-silenced
+ * - scopedErrors: errors thrown or logged with their local context
+ * - tracedErrors: errors logged with their stack trace
+ * - screamedErrors: never @-silenced errors
+ *
+ * Each error level can be logged by a dedicated PSR-3 logger object.
+ * Screaming only applies to logging.
+ * Throwing takes precedence over logging.
+ * Uncaught exceptions are logged as E_ERROR.
+ * E_DEPRECATED and E_USER_DEPRECATED levels never throw.
+ * E_RECOVERABLE_ERROR and E_USER_ERROR levels always throw.
+ * Non catchable errors that can be detected at shutdown time are logged when the scream bit field allows so.
+ * As errors have a performance cost, repeated errors are all logged, so that the developer
+ * can see them and weight them as more important to fix than others of the same level.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ *
+ * @final
+ */
+class ErrorHandler
+{
+    private $levels = [
+        E_COMPILE_ERROR => 'Compile Error',
+        E_COMPILE_WARNING => 'Compile Warning',
+        E_CORE_ERROR => 'Core Error',
+        E_CORE_WARNING => 'Core Warning',
+        E_DEPRECATED => 'Deprecated',
+        E_ERROR => 'Error',
+        E_NOTICE => 'Notice',
+        E_PARSE => 'Parse Error',
+        E_RECOVERABLE_ERROR => 'Catchable Fatal Error',
+        E_STRICT => 'Runtime Notice',
+        E_USER_DEPRECATED => 'User Deprecated',
+        E_USER_ERROR => 'User Error',
+        E_USER_NOTICE => 'User Notice',
+        E_USER_WARNING => 'User Warning',
+        E_WARNING => 'Warning',
+    ];
+
+    private $loggers = [
+        E_COMPILE_ERROR => [null, LogLevel::CRITICAL],
+        E_COMPILE_WARNING => [null, LogLevel::WARNING],
+        E_CORE_ERROR => [null, LogLevel::CRITICAL],
+        E_CORE_WARNING => [null, LogLevel::WARNING],
+        E_DEPRECATED => [null, LogLevel::INFO],
+        E_ERROR => [null, LogLevel::CRITICAL],
+        E_NOTICE => [null, LogLevel::WARNING],
+        E_PARSE => [null, LogLevel::CRITICAL],
+        E_RECOVERABLE_ERROR => [null, LogLevel::CRITICAL],
+        E_STRICT => [null, LogLevel::WARNING],
+        E_USER_DEPRECATED => [null, LogLevel::INFO],
+        E_USER_ERROR => [null, LogLevel::CRITICAL],
+        E_USER_NOTICE => [null, LogLevel::WARNING],
+        E_USER_WARNING => [null, LogLevel::WARNING],
+        E_WARNING => [null, LogLevel::WARNING],
+    ];
+
+    private $thrownErrors = 0x1FFF; // E_ALL - E_DEPRECATED - E_USER_DEPRECATED
+    private $scopedErrors = 0x1FFF; // E_ALL - E_DEPRECATED - E_USER_DEPRECATED
+    private $tracedErrors = 0x77FB; // E_ALL - E_STRICT - E_PARSE
+    private $screamedErrors = 0x55; // E_ERROR + E_CORE_ERROR + E_COMPILE_ERROR + E_PARSE
+    private $loggedErrors = 0;
+    private $traceReflector;
+
+    private $isRecursive = 0;
+    private $isRoot = false;
+    private $exceptionHandler;
+    private $bootstrappingLogger;
+
+    private static $reservedMemory;
+    private static $toStringException = null;
+    private static $silencedErrorCache = [];
+    private static $silencedErrorCount = 0;
+    private static $exitCode = 0;
+
+    /**
+     * Registers the error handler.
+     *
+     * @param self|null $handler The handler to register
+     * @param bool      $replace Whether to replace or not any existing handler
+     *
+     * @return self The registered error handler
+     */
+    public static function register(self $handler = null, $replace = true)
+    {
+        if (null === self::$reservedMemory) {
+            self::$reservedMemory = str_repeat('x', 10240);
+            register_shutdown_function(__CLASS__.'::handleFatalError');
+        }
+
+        if ($handlerIsNew = null === $handler) {
+            $handler = new static();
+        }
+
+        if (null === $prev = set_error_handler([$handler, 'handleError'])) {
+            restore_error_handler();
+            // Specifying the error types earlier would expose us to https://bugs.php.net/63206
+            set_error_handler([$handler, 'handleError'], $handler->thrownErrors | $handler->loggedErrors);
+            $handler->isRoot = true;
+        }
+
+        if ($handlerIsNew && \is_array($prev) && $prev[0] instanceof self) {
+            $handler = $prev[0];
+            $replace = false;
+        }
+        if (!$replace && $prev) {
+            restore_error_handler();
+            $handlerIsRegistered = \is_array($prev) && $handler === $prev[0];
+        } else {
+            $handlerIsRegistered = true;
+        }
+        if (\is_array($prev = set_exception_handler([$handler, 'handleException'])) && $prev[0] instanceof self) {
+            restore_exception_handler();
+            if (!$handlerIsRegistered) {
+                $handler = $prev[0];
+            } elseif ($handler !== $prev[0] && $replace) {
+                set_exception_handler([$handler, 'handleException']);
+                $p = $prev[0]->setExceptionHandler(null);
+                $handler->setExceptionHandler($p);
+                $prev[0]->setExceptionHandler($p);
+            }
+        } else {
+            $handler->setExceptionHandler($prev);
+        }
+
+        $handler->throwAt(E_ALL & $handler->thrownErrors, true);
+
+        return $handler;
+    }
+
+    public function __construct(BufferingLogger $bootstrappingLogger = null)
+    {
+        if ($bootstrappingLogger) {
+            $this->bootstrappingLogger = $bootstrappingLogger;
+            $this->setDefaultLogger($bootstrappingLogger);
+        }
+        $this->traceReflector = new \ReflectionProperty('Exception', 'trace');
+        $this->traceReflector->setAccessible(true);
+    }
+
+    /**
+     * Sets a logger to non assigned errors levels.
+     *
+     * @param LoggerInterface $logger  A PSR-3 logger to put as default for the given levels
+     * @param array|int       $levels  An array map of E_* to LogLevel::* or an integer bit field of E_* constants
+     * @param bool            $replace Whether to replace or not any existing logger
+     */
+    public function setDefaultLogger(LoggerInterface $logger, $levels = E_ALL, $replace = false)
+    {
+        $loggers = [];
+
+        if (\is_array($levels)) {
+            foreach ($levels as $type => $logLevel) {
+                if (empty($this->loggers[$type][0]) || $replace || $this->loggers[$type][0] === $this->bootstrappingLogger) {
+                    $loggers[$type] = [$logger, $logLevel];
+                }
+            }
+        } else {
+            if (null === $levels) {
+                $levels = E_ALL;
+            }
+            foreach ($this->loggers as $type => $log) {
+                if (($type & $levels) && (empty($log[0]) || $replace || $log[0] === $this->bootstrappingLogger)) {
+                    $log[0] = $logger;
+                    $loggers[$type] = $log;
+                }
+            }
+        }
+
+        $this->setLoggers($loggers);
+    }
+
+    /**
+     * Sets a logger for each error level.
+     *
+     * @param array $loggers Error levels to [LoggerInterface|null, LogLevel::*] map
+     *
+     * @return array The previous map
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function setLoggers(array $loggers)
+    {
+        $prevLogged = $this->loggedErrors;
+        $prev = $this->loggers;
+        $flush = [];
+
+        foreach ($loggers as $type => $log) {
+            if (!isset($prev[$type])) {
+                throw new \InvalidArgumentException('Unknown error type: '.$type);
+            }
+            if (!\is_array($log)) {
+                $log = [$log];
+            } elseif (!\array_key_exists(0, $log)) {
+                throw new \InvalidArgumentException('No logger provided');
+            }
+            if (null === $log[0]) {
+                $this->loggedErrors &= ~$type;
+            } elseif ($log[0] instanceof LoggerInterface) {
+                $this->loggedErrors |= $type;
+            } else {
+                throw new \InvalidArgumentException('Invalid logger provided');
+            }
+            $this->loggers[$type] = $log + $prev[$type];
+
+            if ($this->bootstrappingLogger && $prev[$type][0] === $this->bootstrappingLogger) {
+                $flush[$type] = $type;
+            }
+        }
+        $this->reRegister($prevLogged | $this->thrownErrors);
+
+        if ($flush) {
+            foreach ($this->bootstrappingLogger->cleanLogs() as $log) {
+                $type = $log[2]['exception'] instanceof \ErrorException ? $log[2]['exception']->getSeverity() : E_ERROR;
+                if (!isset($flush[$type])) {
+                    $this->bootstrappingLogger->log($log[0], $log[1], $log[2]);
+                } elseif ($this->loggers[$type][0]) {
+                    $this->loggers[$type][0]->log($this->loggers[$type][1], $log[1], $log[2]);
+                }
+            }
+        }
+
+        return $prev;
+    }
+
+    /**
+     * Sets a user exception handler.
+     *
+     * @param callable $handler A handler that will be called on Exception
+     *
+     * @return callable|null The previous exception handler
+     */
+    public function setExceptionHandler(callable $handler = null)
+    {
+        $prev = $this->exceptionHandler;
+        $this->exceptionHandler = $handler;
+
+        return $prev;
+    }
+
+    /**
+     * Sets the PHP error levels that throw an exception when a PHP error occurs.
+     *
+     * @param int  $levels  A bit field of E_* constants for thrown errors
+     * @param bool $replace Replace or amend the previous value
+     *
+     * @return int The previous value
+     */
+    public function throwAt($levels, $replace = false)
+    {
+        $prev = $this->thrownErrors;
+        $this->thrownErrors = ($levels | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
+        if (!$replace) {
+            $this->thrownErrors |= $prev;
+        }
+        $this->reRegister($prev | $this->loggedErrors);
+
+        return $prev;
+    }
+
+    /**
+     * Sets the PHP error levels for which local variables are preserved.
+     *
+     * @param int  $levels  A bit field of E_* constants for scoped errors
+     * @param bool $replace Replace or amend the previous value
+     *
+     * @return int The previous value
+     */
+    public function scopeAt($levels, $replace = false)
+    {
+        $prev = $this->scopedErrors;
+        $this->scopedErrors = (int) $levels;
+        if (!$replace) {
+            $this->scopedErrors |= $prev;
+        }
+
+        return $prev;
+    }
+
+    /**
+     * Sets the PHP error levels for which the stack trace is preserved.
+     *
+     * @param int  $levels  A bit field of E_* constants for traced errors
+     * @param bool $replace Replace or amend the previous value
+     *
+     * @return int The previous value
+     */
+    public function traceAt($levels, $replace = false)
+    {
+        $prev = $this->tracedErrors;
+        $this->tracedErrors = (int) $levels;
+        if (!$replace) {
+            $this->tracedErrors |= $prev;
+        }
+
+        return $prev;
+    }
+
+    /**
+     * Sets the error levels where the @-operator is ignored.
+     *
+     * @param int  $levels  A bit field of E_* constants for screamed errors
+     * @param bool $replace Replace or amend the previous value
+     *
+     * @return int The previous value
+     */
+    public function screamAt($levels, $replace = false)
+    {
+        $prev = $this->screamedErrors;
+        $this->screamedErrors = (int) $levels;
+        if (!$replace) {
+            $this->screamedErrors |= $prev;
+        }
+
+        return $prev;
+    }
+
+    /**
+     * Re-registers as a PHP error handler if levels changed.
+     */
+    private function reRegister($prev)
+    {
+        if ($prev !== $this->thrownErrors | $this->loggedErrors) {
+            $handler = set_error_handler('var_dump');
+            $handler = \is_array($handler) ? $handler[0] : null;
+            restore_error_handler();
+            if ($handler === $this) {
+                restore_error_handler();
+                if ($this->isRoot) {
+                    set_error_handler([$this, 'handleError'], $this->thrownErrors | $this->loggedErrors);
+                } else {
+                    set_error_handler([$this, 'handleError']);
+                }
+            }
+        }
+    }
+
+    /**
+     * Handles errors by filtering then logging them according to the configured bit fields.
+     *
+     * @return bool Returns false when no handling happens so that the PHP engine can handle the error itself
+     *
+     * @throws \ErrorException When $this->thrownErrors requests so
+     *
+     * @internal
+     */
+    public function handleError(int $type, string $message, string $file, int $line): bool
+    {
+        // @deprecated to be removed in Symfony 5.0
+        if (\PHP_VERSION_ID >= 70300 && $message && '"' === $message[0] && 0 === strpos($message, '"continue') && preg_match('/^"continue(?: \d++)?" targeting switch is equivalent to "break(?: \d++)?"\. Did you mean to use "continue(?: \d++)?"\?$/', $message)) {
+            $type = E_DEPRECATED;
+        }
+
+        // Level is the current error reporting level to manage silent error.
+        $level = error_reporting();
+        $silenced = 0 === ($level & $type);
+        // Strong errors are not authorized to be silenced.
+        $level |= E_RECOVERABLE_ERROR | E_USER_ERROR | E_DEPRECATED | E_USER_DEPRECATED;
+        $log = $this->loggedErrors & $type;
+        $throw = $this->thrownErrors & $type & $level;
+        $type &= $level | $this->screamedErrors;
+
+        if (!$type || (!$log && !$throw)) {
+            return !$silenced && $type && $log;
+        }
+        $scope = $this->scopedErrors & $type;
+
+        if (4 < $numArgs = \func_num_args()) {
+            $context = $scope ? (func_get_arg(4) ?: []) : [];
+        } else {
+            $context = [];
+        }
+
+        if (isset($context['GLOBALS']) && $scope) {
+            $e = $context;                  // Whatever the signature of the method,
+            unset($e['GLOBALS'], $context);
+            $context = $e;
+        }
+
+        if (false !== strpos($message, "class@anonymous\0")) {
+            $logMessage = $this->levels[$type].': '.(new FlattenException())->setMessage($message)->getMessage();
+        } else {
+            $logMessage = $this->levels[$type].': '.$message;
+        }
+
+        if (null !== self::$toStringException) {
+            $errorAsException = self::$toStringException;
+            self::$toStringException = null;
+        } elseif (!$throw && !($type & $level)) {
+            if (!isset(self::$silencedErrorCache[$id = $file.':'.$line])) {
+                $lightTrace = $this->tracedErrors & $type ? $this->cleanTrace(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 5), $type, $file, $line, false) : [];
+                $errorAsException = new SilencedErrorContext($type, $file, $line, isset($lightTrace[1]) ? [$lightTrace[0]] : $lightTrace);
+            } elseif (isset(self::$silencedErrorCache[$id][$message])) {
+                $lightTrace = null;
+                $errorAsException = self::$silencedErrorCache[$id][$message];
+                ++$errorAsException->count;
+            } else {
+                $lightTrace = [];
+                $errorAsException = null;
+            }
+
+            if (100 < ++self::$silencedErrorCount) {
+                self::$silencedErrorCache = $lightTrace = [];
+                self::$silencedErrorCount = 1;
+            }
+            if ($errorAsException) {
+                self::$silencedErrorCache[$id][$message] = $errorAsException;
+            }
+            if (null === $lightTrace) {
+                return true;
+            }
+        } else {
+            $errorAsException = new \ErrorException($logMessage, 0, $type, $file, $line);
+
+            if ($throw || $this->tracedErrors & $type) {
+                $backtrace = $errorAsException->getTrace();
+                $lightTrace = $this->cleanTrace($backtrace, $type, $file, $line, $throw);
+                $this->traceReflector->setValue($errorAsException, $lightTrace);
+            } else {
+                $this->traceReflector->setValue($errorAsException, []);
+                $backtrace = [];
+            }
+        }
+
+        if ($throw) {
+            if (E_USER_ERROR & $type) {
+                for ($i = 1; isset($backtrace[$i]); ++$i) {
+                    if (isset($backtrace[$i]['function'], $backtrace[$i]['type'], $backtrace[$i - 1]['function'])
+                        && '__toString' === $backtrace[$i]['function']
+                        && '->' === $backtrace[$i]['type']
+                        && !isset($backtrace[$i - 1]['class'])
+                        && ('trigger_error' === $backtrace[$i - 1]['function'] || 'user_error' === $backtrace[$i - 1]['function'])
+                    ) {
+                        // Here, we know trigger_error() has been called from __toString().
+                        // PHP triggers a fatal error when throwing from __toString().
+                        // A small convention allows working around the limitation:
+                        // given a caught $e exception in __toString(), quitting the method with
+                        // `return trigger_error($e, E_USER_ERROR);` allows this error handler
+                        // to make $e get through the __toString() barrier.
+
+                        foreach ($context as $e) {
+                            if ($e instanceof \Throwable && $e->__toString() === $message) {
+                                self::$toStringException = $e;
+
+                                return true;
+                            }
+                        }
+
+                        // Display the original error message instead of the default one.
+                        $this->handleException($errorAsException);
+
+                        // Stop the process by giving back the error to the native handler.
+                        return false;
+                    }
+                }
+            }
+
+            throw $errorAsException;
+        }
+
+        if ($this->isRecursive) {
+            $log = 0;
+        } else {
+            if (!\defined('HHVM_VERSION')) {
+                $currentErrorHandler = set_error_handler('var_dump');
+                restore_error_handler();
+            }
+
+            try {
+                $this->isRecursive = true;
+                $level = ($type & $level) ? $this->loggers[$type][1] : LogLevel::DEBUG;
+                $this->loggers[$type][0]->log($level, $logMessage, $errorAsException ? ['exception' => $errorAsException] : []);
+            } finally {
+                $this->isRecursive = false;
+
+                if (!\defined('HHVM_VERSION')) {
+                    set_error_handler($currentErrorHandler);
+                }
+            }
+        }
+
+        return !$silenced && $type && $log;
+    }
+
+    /**
+     * Handles an exception by logging then forwarding it to another handler.
+     *
+     * @param \Exception|\Throwable $exception An exception to handle
+     * @param array                 $error     An array as returned by error_get_last()
+     *
+     * @internal
+     */
+    public function handleException($exception, array $error = null)
+    {
+        if (null === $error) {
+            self::$exitCode = 255;
+        }
+        if (!$exception instanceof \Exception) {
+            $exception = new FatalThrowableError($exception);
+        }
+        $type = $exception instanceof FatalErrorException ? $exception->getSeverity() : E_ERROR;
+        $handlerException = null;
+
+        if (($this->loggedErrors & $type) || $exception instanceof FatalThrowableError) {
+            if (false !== strpos($message = $exception->getMessage(), "class@anonymous\0")) {
+                $message = (new FlattenException())->setMessage($message)->getMessage();
+            }
+            if ($exception instanceof FatalErrorException) {
+                if ($exception instanceof FatalThrowableError) {
+                    $error = [
+                        'type' => $type,
+                        'message' => $message,
+                        'file' => $exception->getFile(),
+                        'line' => $exception->getLine(),
+                    ];
+                } else {
+                    $message = 'Fatal '.$message;
+                }
+            } elseif ($exception instanceof \ErrorException) {
+                $message = 'Uncaught '.$message;
+            } else {
+                $message = 'Uncaught Exception: '.$message;
+            }
+        }
+        if ($this->loggedErrors & $type) {
+            try {
+                $this->loggers[$type][0]->log($this->loggers[$type][1], $message, ['exception' => $exception]);
+            } catch (\Throwable $handlerException) {
+            }
+        }
+        if ($exception instanceof FatalErrorException && !$exception instanceof OutOfMemoryException && $error) {
+            foreach ($this->getFatalErrorHandlers() as $handler) {
+                if ($e = $handler->handleError($error, $exception)) {
+                    $exception = $e;
+                    break;
+                }
+            }
+        }
+        $exceptionHandler = $this->exceptionHandler;
+        $this->exceptionHandler = null;
+        try {
+            if (null !== $exceptionHandler) {
+                return $exceptionHandler($exception);
+            }
+            $handlerException = $handlerException ?: $exception;
+        } catch (\Throwable $handlerException) {
+        }
+        if ($exception === $handlerException) {
+            self::$reservedMemory = null; // Disable the fatal error handler
+            throw $exception; // Give back $exception to the native handler
+        }
+        $this->handleException($handlerException);
+    }
+
+    /**
+     * Shutdown registered function for handling PHP fatal errors.
+     *
+     * @param array $error An array as returned by error_get_last()
+     *
+     * @internal
+     */
+    public static function handleFatalError(array $error = null)
+    {
+        if (null === self::$reservedMemory) {
+            return;
+        }
+
+        $handler = self::$reservedMemory = null;
+        $handlers = [];
+        $previousHandler = null;
+        $sameHandlerLimit = 10;
+
+        while (!\is_array($handler) || !$handler[0] instanceof self) {
+            $handler = set_exception_handler('var_dump');
+            restore_exception_handler();
+
+            if (!$handler) {
+                break;
+            }
+            restore_exception_handler();
+
+            if ($handler !== $previousHandler) {
+                array_unshift($handlers, $handler);
+                $previousHandler = $handler;
+            } elseif (0 === --$sameHandlerLimit) {
+                $handler = null;
+                break;
+            }
+        }
+        foreach ($handlers as $h) {
+            set_exception_handler($h);
+        }
+        if (!$handler) {
+            return;
+        }
+        if ($handler !== $h) {
+            $handler[0]->setExceptionHandler($h);
+        }
+        $handler = $handler[0];
+        $handlers = [];
+
+        if ($exit = null === $error) {
+            $error = error_get_last();
+        }
+
+        if ($error && $error['type'] &= E_PARSE | E_ERROR | E_CORE_ERROR | E_COMPILE_ERROR) {
+            // Let's not throw anymore but keep logging
+            $handler->throwAt(0, true);
+            $trace = isset($error['backtrace']) ? $error['backtrace'] : null;
+
+            if (0 === strpos($error['message'], 'Allowed memory') || 0 === strpos($error['message'], 'Out of memory')) {
+                $exception = new OutOfMemoryException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, false, $trace);
+            } else {
+                $exception = new FatalErrorException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, true, $trace);
+            }
+        } else {
+            $exception = null;
+        }
+
+        try {
+            if (null !== $exception) {
+                self::$exitCode = 255;
+                $handler->handleException($exception, $error);
+            }
+        } catch (FatalErrorException $e) {
+            // Ignore this re-throw
+        }
+
+        if ($exit && self::$exitCode) {
+            $exitCode = self::$exitCode;
+            register_shutdown_function('register_shutdown_function', function () use ($exitCode) { exit($exitCode); });
+        }
+    }
+
+    /**
+     * Gets the fatal error handlers.
+     *
+     * Override this method if you want to define more fatal error handlers.
+     *
+     * @return FatalErrorHandlerInterface[] An array of FatalErrorHandlerInterface
+     */
+    protected function getFatalErrorHandlers()
+    {
+        return [
+            new UndefinedFunctionFatalErrorHandler(),
+            new UndefinedMethodFatalErrorHandler(),
+            new ClassNotFoundFatalErrorHandler(),
+        ];
+    }
+
+    /**
+     * Cleans the trace by removing function arguments and the frames added by the error handler and DebugClassLoader.
+     */
+    private function cleanTrace($backtrace, $type, $file, $line, $throw)
+    {
+        $lightTrace = $backtrace;
+
+        for ($i = 0; isset($backtrace[$i]); ++$i) {
+            if (isset($backtrace[$i]['file'], $backtrace[$i]['line']) && $backtrace[$i]['line'] === $line && $backtrace[$i]['file'] === $file) {
+                $lightTrace = \array_slice($lightTrace, 1 + $i);
+                break;
+            }
+        }
+        if (class_exists(DebugClassLoader::class, false)) {
+            for ($i = \count($lightTrace) - 2; 0 < $i; --$i) {
+                if (DebugClassLoader::class === ($lightTrace[$i]['class'] ?? null)) {
+                    array_splice($lightTrace, --$i, 2);
+                }
+            }
+        }
+        if (!($throw || $this->scopedErrors & $type)) {
+            for ($i = 0; isset($lightTrace[$i]); ++$i) {
+                unset($lightTrace[$i]['args'], $lightTrace[$i]['object']);
+            }
+        }
+
+        return $lightTrace;
+    }
+}

src/Symfony/Component/ErrorHandler/ErrorRenderer/ErrorRenderer.php

@@ -0,0 +1,71 @@
+<?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\ErrorHandler\ErrorRenderer;
+
+use Symfony\Component\ErrorHandler\Exception\ErrorRendererNotFoundException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+/**
+ * Renders an Exception that represents a Response content.
+ *
+ * @see ErrorRendererInterface
+ *
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+class ErrorRenderer
+{
+    private $renderers = [];
+
+    /**
+     * @param ErrorRendererInterface[] $renderers
+     */
+    public function __construct(array $renderers)
+    {
+        foreach ($renderers as $renderer) {
+            if (!$renderer instanceof ErrorRendererInterface) {
+                throw new \InvalidArgumentException(sprintf('Error renderer "%s" must implement "%s".', \get_class($renderer), ErrorRendererInterface::class));
+            }
+
+            $this->addRenderer($renderer, $renderer::getFormat());
+        }
+    }
+
+    public function addRenderer(ErrorRendererInterface $renderer, string $format): self
+    {
+        $this->renderers[$format] = $renderer;
+
+        return $this;
+    }
+
+    /**
+     * Renders an Exception and returns the Response content.
+     *
+     * @param \Exception|FlattenException $exception An \Exception or FlattenException instance
+     * @param string                      $format    The request format (html, json, xml, etc.)
+     *
+     * @return string The Response content as a string
+     *
+     * @throws ErrorRendererNotFoundException if no renderer is found
+     */
+    public function render($exception, string $format = 'html'): string
+    {
+        if (!isset($this->renderers[$format])) {
+            throw new ErrorRendererNotFoundException(sprintf('No error renderer found for format "%s".', $format));
+        }
+
+        if (!$exception instanceof FlattenException) {
+            $exception = FlattenException::create($exception);
+        }
+
+        return $this->renderers[$format]->render($exception);
+    }
+}

src/Symfony/Component/ErrorHandler/ErrorRenderer/ErrorRendererInterface.php

@@ -0,0 +1,36 @@
+<?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\ErrorHandler\ErrorRenderer;
+
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+/**
+ * Interface implemented by all error renderers.
+ *
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+interface ErrorRendererInterface
+{
+    /**
+     * Gets the format of the content.
+     *
+     * @return string The content format
+     */
+    public static function getFormat(): string;
+
+    /**
+     * Renders an Exception and returns the Response content.
+     *
+     * @return string The Response content as a string
+     */
+    public function render(FlattenException $exception): string;
+}

src/Symfony/Component/ErrorHandler/ErrorRenderer/JsonErrorRenderer.php

@@ -0,0 +1,52 @@
+<?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\ErrorHandler\ErrorRenderer;
+
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+/**
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+class JsonErrorRenderer implements ErrorRendererInterface
+{
+    private $debug;
+
+    public function __construct(bool $debug = true)
+    {
+        $this->debug = $debug;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getFormat(): string
+    {
+        return 'json';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function render(FlattenException $exception): string
+    {
+        $content = [
+            'title' => $exception->getTitle(),
+            'status' => $exception->getStatusCode(),
+            'detail' => $exception->getMessage(),
+        ];
+        if ($this->debug) {
+            $content['exceptions'] = $exception->toArray();
+        }
+
+        return (string) json_encode($content);
+    }
+}

src/Symfony/Component/ErrorHandler/ErrorRenderer/TxtErrorRenderer.php

@@ -0,0 +1,98 @@
+<?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\ErrorHandler\ErrorRenderer;
+
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+/**
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+class TxtErrorRenderer implements ErrorRendererInterface
+{
+    private $debug;
+    private $charset;
+
+    public function __construct(bool $debug = true, string $charset = null)
+    {
+        $this->debug = $debug;
+        $this->charset = $charset ?: (ini_get('default_charset') ?: 'UTF-8');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getFormat(): string
+    {
+        return 'txt';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function render(FlattenException $exception): string
+    {
+        $content = sprintf("[title] %s\n", $exception->getTitle());
+        $content .= sprintf("[status] %s\n", $exception->getStatusCode());
+        $content .= sprintf("[detail] %s\n", $exception->getMessage());
+
+        if ($this->debug) {
+            foreach ($exception->toArray() as $i => $e) {
+                $content .= sprintf("[%d] %s: %s\n", $i + 1, $e['class'], $e['message']);
+                foreach ($e['trace'] as $trace) {
+                    if ($trace['function']) {
+                        $content .= sprintf('at %s%s%s(%s) ', $trace['class'], $trace['type'], $trace['function'], $this->formatArgs($trace['args']));
+                    }
+                    if (isset($trace['file'], $trace['line'])) {
+                        $content .= $this->formatPath($trace['file'], $trace['line']);
+                    }
+                    $content .= "\n";
+                }
+            }
+        }
+
+        return $content;
+    }
+
+    private function formatPath(string $path, int $line): string
+    {
+        $file = preg_match('#[^/\\\\]*+$#', $path, $file) ? $file[0] : $path;
+
+        return sprintf('in %s %s', $path, 0 < $line ? ' line '.$line : '');
+    }
+
+    /**
+     * Formats an array as a string.
+     */
+    private function formatArgs(array $args): string
+    {
+        $result = [];
+        foreach ($args as $key => $item) {
+            if ('object' === $item[0]) {
+                $formattedValue = sprintf('object(%s)', $item[1]);
+            } elseif ('array' === $item[0]) {
+                $formattedValue = sprintf('array(%s)', \is_array($item[1]) ? $this->formatArgs($item[1]) : $item[1]);
+            } elseif ('null' === $item[0]) {
+                $formattedValue = 'null';
+            } elseif ('boolean' === $item[0]) {
+                $formattedValue = strtolower(var_export($item[1], true));
+            } elseif ('resource' === $item[0]) {
+                $formattedValue = 'resource';
+            } else {
+                $formattedValue = str_replace("\n", '', var_export($item[1], true));
+            }
+
+            $result[] = \is_int($key) ? $formattedValue : sprintf("'%s' => %s", $key, $formattedValue);
+        }
+
+        return implode(', ', $result);
+    }
+}

src/Symfony/Component/ErrorHandler/ErrorRenderer/XmlErrorRenderer.php

@@ -0,0 +1,117 @@
+<?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\ErrorHandler\ErrorRenderer;
+
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+/**
+ * @author Yonel Ceruto <yonelceruto@gmail.com>
+ */
+class XmlErrorRenderer implements ErrorRendererInterface
+{
+    private $debug;
+    private $charset;
+
+    public function __construct(bool $debug = true, string $charset = null)
+    {
+        $this->debug = $debug;
+        $this->charset = $charset ?: (ini_get('default_charset') ?: 'UTF-8');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getFormat(): string
+    {
+        return 'xml';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function render(FlattenException $exception): string
+    {
+        $message = $this->escapeXml($exception->getMessage());
+
+        $exceptions = '';
+        if ($this->debug) {
+            $exceptions .= '<exceptions>';
+            foreach ($exception->toArray() as $e) {
+                $exceptions .= sprintf('<exception class="%s" message="%s"><traces>', $e['class'], $this->escapeXml($e['message']));
+                foreach ($e['trace'] as $trace) {
+                    $exceptions .= '<trace>';
+                    if ($trace['function']) {
+                        $exceptions .= sprintf('at %s%s%s(%s) ', $trace['class'], $trace['type'], $trace['function'], $this->formatArgs($trace['args']));
+                    }
+                    if (isset($trace['file'], $trace['line'])) {
+                        $exceptions .= $this->formatPath($trace['file'], $trace['line']);
+                    }
+                    $exceptions .= '</trace>';
+                }
+                $exceptions .= '</traces></exception>';
+            }
+            $exceptions .= '</exceptions>';
+        }
+
+        return <<<EOF
+<?xml version="1.0" encoding="{$this->charset}" ?>
+<problem xmlns="urn:ietf:rfc:7807">
+    <title>{$exception->getTitle()}</title>
+    <status>{$exception->getStatusCode()}</status>
+    <detail>{$message}</detail>
+    {$exceptions}
+</problem>
+EOF;
+    }
+
+    /**
+     * XML-encodes a string.
+     */
+    private function escapeXml(string $str): string
+    {
+        return htmlspecialchars($str, ENT_COMPAT | ENT_SUBSTITUTE, $this->charset);
+    }
+
+    private function formatPath(string $path, int $line): string
+    {
+        $file = $this->escapeXml(preg_match('#[^/\\\\]*+$#', $path, $file) ? $file[0] : $path);
+
+        return sprintf('in %s %s', $this->escapeXml($path), 0 < $line ? ' line '.$line : '');
+    }
+
+    /**
+     * Formats an array as a string.
+     */
+    private function formatArgs(array $args): string
+    {
+        $result = [];
+        foreach ($args as $key => $item) {
+            if ('object' === $item[0]) {
+                $formattedValue = sprintf('object(%s)', $item[1]);
+            } elseif ('array' === $item[0]) {
+                $formattedValue = sprintf('array(%s)', \is_array($item[1]) ? $this->formatArgs($item[1]) : $item[1]);
+            } elseif ('null' === $item[0]) {
+                $formattedValue = 'null';
+            } elseif ('boolean' === $item[0]) {
+                $formattedValue = strtolower(var_export($item[1], true));
+            } elseif ('resource' === $item[0]) {
+                $formattedValue = 'resource';
+            } else {
+                $formattedValue = str_replace("\n", '', $this->escapeXml(var_export($item[1], true)));
+            }
+
+            $result[] = \is_int($key) ? $formattedValue : sprintf("'%s' => %s", $this->escapeXml($key), $formattedValue);
+        }
+
+        return implode(', ', $result);
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/ClassNotFoundException.php

@@ -0,0 +1,36 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Class (or Trait or Interface) Not Found Exception.
+ *
+ * @author Konstanton Myakshin <koc-dp@yandex.ru>
+ */
+class ClassNotFoundException extends FatalErrorException
+{
+    public function __construct(string $message, \ErrorException $previous)
+    {
+        parent::__construct(
+            $message,
+            $previous->getCode(),
+            $previous->getSeverity(),
+            $previous->getFile(),
+            $previous->getLine(),
+            null,
+            true,
+            null,
+            $previous->getPrevious()
+        );
+        $this->setTrace($previous->getTrace());
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/ErrorRendererNotFoundException.php

@@ -0,0 +1,16 @@
+<?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\ErrorHandler\Exception;
+
+class ErrorRendererNotFoundException extends \RuntimeException
+{
+}

src/Symfony/Component/ErrorHandler/Exception/FatalErrorException.php

@@ -0,0 +1,77 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Fatal Error Exception.
+ *
+ * @author Konstanton Myakshin <koc-dp@yandex.ru>
+ */
+class FatalErrorException extends \ErrorException
+{
+    public function __construct(string $message, int $code, int $severity, string $filename, int $lineno, int $traceOffset = null, bool $traceArgs = true, array $trace = null, \Throwable $previous = null)
+    {
+        parent::__construct($message, $code, $severity, $filename, $lineno, $previous);
+
+        if (null !== $trace) {
+            if (!$traceArgs) {
+                foreach ($trace as &$frame) {
+                    unset($frame['args'], $frame['this'], $frame);
+                }
+            }
+
+            $this->setTrace($trace);
+        } elseif (null !== $traceOffset) {
+            if (\function_exists('xdebug_get_function_stack')) {
+                $trace = xdebug_get_function_stack();
+                if (0 < $traceOffset) {
+                    array_splice($trace, -$traceOffset);
+                }
+
+                foreach ($trace as &$frame) {
+                    if (!isset($frame['type'])) {
+                        // XDebug pre 2.1.1 doesn't currently set the call type key http://bugs.xdebug.org/view.php?id=695
+                        if (isset($frame['class'])) {
+                            $frame['type'] = '::';
+                        }
+                    } elseif ('dynamic' === $frame['type']) {
+                        $frame['type'] = '->';
+                    } elseif ('static' === $frame['type']) {
+                        $frame['type'] = '::';
+                    }
+
+                    // XDebug also has a different name for the parameters array
+                    if (!$traceArgs) {
+                        unset($frame['params'], $frame['args']);
+                    } elseif (isset($frame['params']) && !isset($frame['args'])) {
+                        $frame['args'] = $frame['params'];
+                        unset($frame['params']);
+                    }
+                }
+
+                unset($frame);
+                $trace = array_reverse($trace);
+            } else {
+                $trace = [];
+            }
+
+            $this->setTrace($trace);
+        }
+    }
+
+    protected function setTrace($trace)
+    {
+        $traceReflector = new \ReflectionProperty('Exception', 'trace');
+        $traceReflector->setAccessible(true);
+        $traceReflector->setValue($this, $trace);
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/FatalThrowableError.php

@@ -0,0 +1,51 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Fatal Throwable Error.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class FatalThrowableError extends FatalErrorException
+{
+    private $originalClassName;
+
+    public function __construct(\Throwable $e)
+    {
+        $this->originalClassName = \get_class($e);
+
+        if ($e instanceof \ParseError) {
+            $severity = E_PARSE;
+        } elseif ($e instanceof \TypeError) {
+            $severity = E_RECOVERABLE_ERROR;
+        } else {
+            $severity = E_ERROR;
+        }
+
+        \ErrorException::__construct(
+            $e->getMessage(),
+            $e->getCode(),
+            $severity,
+            $e->getFile(),
+            $e->getLine(),
+            $e->getPrevious()
+        );
+
+        $this->setTrace($e->getTrace());
+    }
+
+    public function getOriginalClassName(): string
+    {
+        return $this->originalClassName;
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/FlattenException.php

@@ -0,0 +1,380 @@
+<?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\ErrorHandler\Exception;
+
+use Symfony\Component\HttpFoundation\Exception\RequestExceptionInterface;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
+
+/**
+ * FlattenException wraps a PHP Error or Exception to be able to serialize it.
+ *
+ * Basically, this class removes all objects from the trace.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class FlattenException
+{
+    private $title;
+    private $message;
+    private $code;
+    private $previous;
+    private $trace;
+    private $traceAsString;
+    private $class;
+    private $statusCode;
+    private $headers;
+    private $file;
+    private $line;
+
+    public static function create(\Exception $exception, $statusCode = null, array $headers = [])
+    {
+        return static::createFromThrowable($exception, $statusCode, $headers);
+    }
+
+    public static function createFromThrowable(\Throwable $exception, ?int $statusCode = null, array $headers = []): self
+    {
+        $e = new static();
+        $e->setMessage($exception->getMessage());
+        $e->setCode($exception->getCode());
+
+        if ($exception instanceof HttpExceptionInterface) {
+            $statusCode = $exception->getStatusCode();
+            $headers = array_merge($headers, $exception->getHeaders());
+        } elseif ($exception instanceof RequestExceptionInterface) {
+            $statusCode = 400;
+        }
+
+        if (null === $statusCode) {
+            $statusCode = 500;
+        }
+
+        if (class_exists(Response::class) && isset(Response::$statusTexts[$statusCode])) {
+            $title = Response::$statusTexts[$statusCode];
+        } else {
+            $title = 'Whoops, looks like something went wrong.';
+        }
+
+        $e->setTitle($title);
+        $e->setStatusCode($statusCode);
+        $e->setHeaders($headers);
+        $e->setTraceFromThrowable($exception);
+        $e->setClass($exception instanceof FatalThrowableError ? $exception->getOriginalClassName() : \get_class($exception));
+        $e->setFile($exception->getFile());
+        $e->setLine($exception->getLine());
+
+        $previous = $exception->getPrevious();
+
+        if ($previous instanceof \Throwable) {
+            $e->setPrevious(static::createFromThrowable($previous));
+        }
+
+        return $e;
+    }
+
+    public function toArray()
+    {
+        $exceptions = [];
+        foreach (array_merge([$this], $this->getAllPrevious()) as $exception) {
+            $exceptions[] = [
+                'message' => $exception->getMessage(),
+                'class' => $exception->getClass(),
+                'trace' => $exception->getTrace(),
+            ];
+        }
+
+        return $exceptions;
+    }
+
+    public function getStatusCode()
+    {
+        return $this->statusCode;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setStatusCode($code)
+    {
+        $this->statusCode = $code;
+
+        return $this;
+    }
+
+    public function getHeaders()
+    {
+        return $this->headers;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setHeaders(array $headers)
+    {
+        $this->headers = $headers;
+
+        return $this;
+    }
+
+    public function getClass()
+    {
+        return $this->class;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setClass($class)
+    {
+        $this->class = 'c' === $class[0] && 0 === strpos($class, "class@anonymous\0") ? get_parent_class($class).'@anonymous' : $class;
+
+        return $this;
+    }
+
+    public function getFile()
+    {
+        return $this->file;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setFile($file)
+    {
+        $this->file = $file;
+
+        return $this;
+    }
+
+    public function getLine()
+    {
+        return $this->line;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setLine($line)
+    {
+        $this->line = $line;
+
+        return $this;
+    }
+
+    public function getTitle()
+    {
+        return $this->title;
+    }
+
+    public function setTitle(string $title): self
+    {
+        $this->title = $title;
+
+        return $this;
+    }
+
+    public function getMessage()
+    {
+        return $this->message;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setMessage($message)
+    {
+        if (false !== strpos($message, "class@anonymous\0")) {
+            $message = preg_replace_callback('/class@anonymous\x00.*?\.php0x?[0-9a-fA-F]++/', function ($m) {
+                return class_exists($m[0], false) ? get_parent_class($m[0]).'@anonymous' : $m[0];
+            }, $message);
+        }
+
+        $this->message = $message;
+
+        return $this;
+    }
+
+    public function getCode()
+    {
+        return $this->code;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setCode($code)
+    {
+        $this->code = $code;
+
+        return $this;
+    }
+
+    public function getPrevious()
+    {
+        return $this->previous;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setPrevious(self $previous)
+    {
+        $this->previous = $previous;
+
+        return $this;
+    }
+
+    public function getAllPrevious()
+    {
+        $exceptions = [];
+        $e = $this;
+        while ($e = $e->getPrevious()) {
+            $exceptions[] = $e;
+        }
+
+        return $exceptions;
+    }
+
+    public function getTrace()
+    {
+        return $this->trace;
+    }
+
+    /**
+     * @deprecated since 4.1, use {@see setTraceFromThrowable()} instead.
+     */
+    public function setTraceFromException(\Exception $exception)
+    {
+        @trigger_error(sprintf('The "%s()" method is deprecated since Symfony 4.1, use "setTraceFromThrowable()" instead.', __METHOD__), E_USER_DEPRECATED);
+
+        $this->setTraceFromThrowable($exception);
+    }
+
+    public function setTraceFromThrowable(\Throwable $throwable)
+    {
+        $this->traceAsString = $throwable->getTraceAsString();
+
+        return $this->setTrace($throwable->getTrace(), $throwable->getFile(), $throwable->getLine());
+    }
+
+    /**
+     * @return $this
+     */
+    public function setTrace($trace, $file, $line)
+    {
+        $this->trace = [];
+        $this->trace[] = [
+            'namespace' => '',
+            'short_class' => '',
+            'class' => '',
+            'type' => '',
+            'function' => '',
+            'file' => $file,
+            'line' => $line,
+            'args' => [],
+        ];
+        foreach ($trace as $entry) {
+            $class = '';
+            $namespace = '';
+            if (isset($entry['class'])) {
+                $parts = explode('\\', $entry['class']);
+                $class = array_pop($parts);
+                $namespace = implode('\\', $parts);
+            }
+
+            $this->trace[] = [
+                'namespace' => $namespace,
+                'short_class' => $class,
+                'class' => isset($entry['class']) ? $entry['class'] : '',
+                'type' => isset($entry['type']) ? $entry['type'] : '',
+                'function' => isset($entry['function']) ? $entry['function'] : null,
+                'file' => isset($entry['file']) ? $entry['file'] : null,
+                'line' => isset($entry['line']) ? $entry['line'] : null,
+                'args' => isset($entry['args']) ? $this->flattenArgs($entry['args']) : [],
+            ];
+        }
+
+        return $this;
+    }
+
+    private function flattenArgs($args, $level = 0, &$count = 0)
+    {
+        $result = [];
+        foreach ($args as $key => $value) {
+            if (++$count > 1e4) {
+                return ['array', '*SKIPPED over 10000 entries*'];
+            }
+            if ($value instanceof \__PHP_Incomplete_Class) {
+                // is_object() returns false on PHP<=7.1
+                $result[$key] = ['incomplete-object', $this->getClassNameFromIncomplete($value)];
+            } elseif (\is_object($value)) {
+                $result[$key] = ['object', \get_class($value)];
+            } elseif (\is_array($value)) {
+                if ($level > 10) {
+                    $result[$key] = ['array', '*DEEP NESTED ARRAY*'];
+                } else {
+                    $result[$key] = ['array', $this->flattenArgs($value, $level + 1, $count)];
+                }
+            } elseif (null === $value) {
+                $result[$key] = ['null', null];
+            } elseif (\is_bool($value)) {
+                $result[$key] = ['boolean', $value];
+            } elseif (\is_int($value)) {
+                $result[$key] = ['integer', $value];
+            } elseif (\is_float($value)) {
+                $result[$key] = ['float', $value];
+            } elseif (\is_resource($value)) {
+                $result[$key] = ['resource', get_resource_type($value)];
+            } else {
+                $result[$key] = ['string', (string) $value];
+            }
+        }
+
+        return $result;
+    }
+
+    private function getClassNameFromIncomplete(\__PHP_Incomplete_Class $value)
+    {
+        $array = new \ArrayObject($value);
+
+        return $array['__PHP_Incomplete_Class_Name'];
+    }
+
+    public function getTraceAsString()
+    {
+        return $this->traceAsString;
+    }
+
+    public function getAsString()
+    {
+        $message = '';
+        $next = false;
+
+        foreach (array_reverse(array_merge([$this], $this->getAllPrevious())) as $exception) {
+            if ($next) {
+                $message .= 'Next ';
+            } else {
+                $next = true;
+            }
+            $message .= $exception->getClass();
+
+            if ('' != $exception->getMessage()) {
+                $message .= ': '.$exception->getMessage();
+            }
+
+            $message .= ' in '.$exception->getFile().':'.$exception->getLine().
+                "\nStack trace:\n".$exception->getTraceAsString()."\n\n";
+        }
+
+        return rtrim($message);
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/OutOfMemoryException.php

@@ -0,0 +1,21 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Out of memory exception.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class OutOfMemoryException extends FatalErrorException
+{
+}

src/Symfony/Component/ErrorHandler/Exception/SilencedErrorContext.php

@@ -0,0 +1,67 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Data Object that represents a Silenced Error.
+ *
+ * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ */
+class SilencedErrorContext implements \JsonSerializable
+{
+    public $count = 1;
+
+    private $severity;
+    private $file;
+    private $line;
+    private $trace;
+
+    public function __construct(int $severity, string $file, int $line, array $trace = [], int $count = 1)
+    {
+        $this->severity = $severity;
+        $this->file = $file;
+        $this->line = $line;
+        $this->trace = $trace;
+        $this->count = $count;
+    }
+
+    public function getSeverity()
+    {
+        return $this->severity;
+    }
+
+    public function getFile()
+    {
+        return $this->file;
+    }
+
+    public function getLine()
+    {
+        return $this->line;
+    }
+
+    public function getTrace()
+    {
+        return $this->trace;
+    }
+
+    public function JsonSerialize()
+    {
+        return [
+            'severity' => $this->severity,
+            'file' => $this->file,
+            'line' => $this->line,
+            'trace' => $this->trace,
+            'count' => $this->count,
+        ];
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/UndefinedFunctionException.php

@@ -0,0 +1,36 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Undefined Function Exception.
+ *
+ * @author Konstanton Myakshin <koc-dp@yandex.ru>
+ */
+class UndefinedFunctionException extends FatalErrorException
+{
+    public function __construct(string $message, \ErrorException $previous)
+    {
+        parent::__construct(
+            $message,
+            $previous->getCode(),
+            $previous->getSeverity(),
+            $previous->getFile(),
+            $previous->getLine(),
+            null,
+            true,
+            null,
+            $previous->getPrevious()
+        );
+        $this->setTrace($previous->getTrace());
+    }
+}

src/Symfony/Component/ErrorHandler/Exception/UndefinedMethodException.php

@@ -0,0 +1,36 @@
+<?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\ErrorHandler\Exception;
+
+/**
+ * Undefined Method Exception.
+ *
+ * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ */
+class UndefinedMethodException extends FatalErrorException
+{
+    public function __construct(string $message, \ErrorException $previous)
+    {
+        parent::__construct(
+            $message,
+            $previous->getCode(),
+            $previous->getSeverity(),
+            $previous->getFile(),
+            $previous->getLine(),
+            null,
+            true,
+            null,
+            $previous->getPrevious()
+        );
+        $this->setTrace($previous->getTrace());
+    }
+}

src/Symfony/Component/ErrorHandler/ExceptionHandler.php

@@ -0,0 +1,177 @@
+<?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\ErrorHandler;
+
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\OutOfMemoryException;
+use Symfony\Component\HttpKernel\Debug\FileLinkFormatter;
+
+/**
+ * ExceptionHandler converts an exception to a Response object.
+ *
+ * It is mostly useful in debug mode to replace the default PHP/XDebug
+ * output with something prettier and more useful.
+ *
+ * As this class is mainly used during Kernel boot, where nothing is yet
+ * available, the Response content is always HTML.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @final
+ */
+class ExceptionHandler
+{
+    private $charset;
+    private $errorRenderer;
+    private $handler;
+    private $caughtBuffer;
+    private $caughtLength;
+
+    /**
+     * Registers the exception handler.
+     *
+     * @param bool        $debug          Enable/disable debug mode, where the stack trace is displayed
+     * @param string|null $charset        The charset used by exception messages
+     * @param string|null $fileLinkFormat The IDE link template
+     *
+     * @return static
+     */
+    public static function register($debug = true, $charset = null, $fileLinkFormat = null)
+    {
+        $handler = new static($debug, $charset, $fileLinkFormat);
+
+        $prev = set_exception_handler([$handler, 'handle']);
+        if (\is_array($prev) && $prev[0] instanceof ErrorHandler) {
+            restore_exception_handler();
+            $prev[0]->setExceptionHandler([$handler, 'handle']);
+        }
+
+        return $handler;
+    }
+
+    public function __construct(bool $debug = true, string $charset = null, $fileLinkFormat = null, HtmlErrorRenderer $errorRenderer = null)
+    {
+        $this->charset = $charset ?: ini_get('default_charset') ?: 'UTF-8';
+        $this->errorRenderer = $errorRenderer ?? new HtmlErrorRenderer($debug, $this->charset, $fileLinkFormat);
+    }
+
+    /**
+     * Sets the format for links to source files.
+     *
+     * @param string|FileLinkFormatter $fileLinkFormat The format for links to source files
+     *
+     * @return string The previous file link format
+     */
+    public function setFileLinkFormat($fileLinkFormat)
+    {
+        return $this->errorRenderer->setFileLinkFormat($fileLinkFormat);
+    }
+
+    /**
+     * Sets a user exception handler.
+     *
+     * @param callable $handler An handler that will be called on Exception
+     *
+     * @return callable|null The previous exception handler if any
+     */
+    public function setHandler(callable $handler = null)
+    {
+        $old = $this->handler;
+        $this->handler = $handler;
+
+        return $old;
+    }
+
+    /**
+     * Sends a response for the given Exception.
+     *
+     * To be as fail-safe as possible, the exception is first handled
+     * by our simple exception handler, then by the user exception handler.
+     * The latter takes precedence and any output from the former is cancelled,
+     * if and only if nothing bad happens in this handling path.
+     */
+    public function handle(\Exception $exception)
+    {
+        if (null === $this->handler || $exception instanceof OutOfMemoryException) {
+            $this->sendPhpResponse($exception);
+
+            return;
+        }
+
+        $caughtLength = $this->caughtLength = 0;
+
+        ob_start(function ($buffer) {
+            $this->caughtBuffer = $buffer;
+
+            return '';
+        });
+
+        $this->sendPhpResponse($exception);
+        while (null === $this->caughtBuffer && ob_end_flush()) {
+            // Empty loop, everything is in the condition
+        }
+        if (isset($this->caughtBuffer[0])) {
+            ob_start(function ($buffer) {
+                if ($this->caughtLength) {
+                    // use substr_replace() instead of substr() for mbstring overloading resistance
+                    $cleanBuffer = substr_replace($buffer, '', 0, $this->caughtLength);
+                    if (isset($cleanBuffer[0])) {
+                        $buffer = $cleanBuffer;
+                    }
+                }
+
+                return $buffer;
+            });
+
+            echo $this->caughtBuffer;
+            $caughtLength = ob_get_length();
+        }
+        $this->caughtBuffer = null;
+
+        try {
+            ($this->handler)($exception);
+            $this->caughtLength = $caughtLength;
+        } catch (\Exception $e) {
+            if (!$caughtLength) {
+                // All handlers failed. Let PHP handle that now.
+                throw $exception;
+            }
+        }
+    }
+
+    /**
+     * Sends the error associated with the given Exception as a plain PHP response.
+     *
+     * This method uses plain PHP functions like header() and echo to output
+     * the response.
+     *
+     * @param \Exception|FlattenException $exception An \Exception or FlattenException instance
+     */
+    public function sendPhpResponse($exception)
+    {
+        if (!$exception instanceof FlattenException) {
+            $exception = FlattenException::create($exception);
+        }
+
+        if (!headers_sent()) {
+            header(sprintf('HTTP/1.0 %s', $exception->getStatusCode()));
+            foreach ($exception->getHeaders() as $name => $value) {
+                header($name.': '.$value, false);
+            }
+            header('Content-Type: text/html; charset='.$this->charset);
+        }
+
+        echo $this->errorRenderer->render($exception);
+    }
+}

src/Symfony/Component/ErrorHandler/FatalErrorHandler/ClassNotFoundFatalErrorHandler.php

@@ -0,0 +1,193 @@
+<?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\ErrorHandler\FatalErrorHandler;
+
+use Composer\Autoload\ClassLoader as ComposerClassLoader;
+use Symfony\Component\ClassLoader\ClassLoader as SymfonyClassLoader;
+use Symfony\Component\Debug\DebugClassLoader;
+use Symfony\Component\ErrorHandler\Exception\ClassNotFoundException;
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+
+/**
+ * ErrorHandler for classes that do not exist.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function handleError(array $error, FatalErrorException $exception)
+    {
+        $messageLen = \strlen($error['message']);
+        $notFoundSuffix = '\' not found';
+        $notFoundSuffixLen = \strlen($notFoundSuffix);
+        if ($notFoundSuffixLen > $messageLen) {
+            return;
+        }
+
+        if (0 !== substr_compare($error['message'], $notFoundSuffix, -$notFoundSuffixLen)) {
+            return;
+        }
+
+        foreach (['class', 'interface', 'trait'] as $typeName) {
+            $prefix = ucfirst($typeName).' \'';
+            $prefixLen = \strlen($prefix);
+            if (0 !== strpos($error['message'], $prefix)) {
+                continue;
+            }
+
+            $fullyQualifiedClassName = substr($error['message'], $prefixLen, -$notFoundSuffixLen);
+            if (false !== $namespaceSeparatorIndex = strrpos($fullyQualifiedClassName, '\\')) {
+                $className = substr($fullyQualifiedClassName, $namespaceSeparatorIndex + 1);
+                $namespacePrefix = substr($fullyQualifiedClassName, 0, $namespaceSeparatorIndex);
+                $message = sprintf('Attempted to load %s "%s" from namespace "%s".', $typeName, $className, $namespacePrefix);
+                $tail = ' for another namespace?';
+            } else {
+                $className = $fullyQualifiedClassName;
+                $message = sprintf('Attempted to load %s "%s" from the global namespace.', $typeName, $className);
+                $tail = '?';
+            }
+
+            if ($candidates = $this->getClassCandidates($className)) {
+                $tail = array_pop($candidates).'"?';
+                if ($candidates) {
+                    $tail = ' for e.g. "'.implode('", "', $candidates).'" or "'.$tail;
+                } else {
+                    $tail = ' for "'.$tail;
+                }
+            }
+            $message .= "\nDid you forget a \"use\" statement".$tail;
+
+            return new ClassNotFoundException($message, $exception);
+        }
+    }
+
+    /**
+     * Tries to guess the full namespace for a given class name.
+     *
+     * By default, it looks for PSR-0 and PSR-4 classes registered via a Symfony or a Composer
+     * autoloader (that should cover all common cases).
+     *
+     * @param string $class A class name (without its namespace)
+     *
+     * @return array An array of possible fully qualified class names
+     */
+    private function getClassCandidates(string $class): array
+    {
+        if (!\is_array($functions = spl_autoload_functions())) {
+            return [];
+        }
+
+        // find Symfony and Composer autoloaders
+        $classes = [];
+
+        foreach ($functions as $function) {
+            if (!\is_array($function)) {
+                continue;
+            }
+            // get class loaders wrapped by DebugClassLoader
+            if ($function[0] instanceof DebugClassLoader) {
+                $function = $function[0]->getClassLoader();
+
+                if (!\is_array($function)) {
+                    continue;
+                }
+            }
+
+            if ($function[0] instanceof ComposerClassLoader || $function[0] instanceof SymfonyClassLoader) {
+                foreach ($function[0]->getPrefixes() as $prefix => $paths) {
+                    foreach ($paths as $path) {
+                        $classes = array_merge($classes, $this->findClassInPath($path, $class, $prefix));
+                    }
+                }
+            }
+            if ($function[0] instanceof ComposerClassLoader) {
+                foreach ($function[0]->getPrefixesPsr4() as $prefix => $paths) {
+                    foreach ($paths as $path) {
+                        $classes = array_merge($classes, $this->findClassInPath($path, $class, $prefix));
+                    }
+                }
+            }
+        }
+
+        return array_unique($classes);
+    }
+
+    private function findClassInPath(string $path, string $class, string $prefix): array
+    {
+        if (!$path = realpath($path.'/'.strtr($prefix, '\\_', '//')) ?: realpath($path.'/'.\dirname(strtr($prefix, '\\_', '//'))) ?: realpath($path)) {
+            return [];
+        }
+
+        $classes = [];
+        $filename = $class.'.php';
+        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($path, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::LEAVES_ONLY) as $file) {
+            if ($filename == $file->getFileName() && $class = $this->convertFileToClass($path, $file->getPathName(), $prefix)) {
+                $classes[] = $class;
+            }
+        }
+
+        return $classes;
+    }
+
+    private function convertFileToClass(string $path, string $file, string $prefix): ?string
+    {
+        $candidates = [
+            // namespaced class
+            $namespacedClass = str_replace([$path.\DIRECTORY_SEPARATOR, '.php', '/'], ['', '', '\\'], $file),
+            // namespaced class (with target dir)
+            $prefix.$namespacedClass,
+            // namespaced class (with target dir and separator)
+            $prefix.'\\'.$namespacedClass,
+            // PEAR class
+            str_replace('\\', '_', $namespacedClass),
+            // PEAR class (with target dir)
+            str_replace('\\', '_', $prefix.$namespacedClass),
+            // PEAR class (with target dir and separator)
+            str_replace('\\', '_', $prefix.'\\'.$namespacedClass),
+        ];
+
+        if ($prefix) {
+            $candidates = array_filter($candidates, function ($candidate) use ($prefix) { return 0 === strpos($candidate, $prefix); });
+        }
+
+        // We cannot use the autoloader here as most of them use require; but if the class
+        // is not found, the new autoloader call will require the file again leading to a
+        // "cannot redeclare class" error.
+        foreach ($candidates as $candidate) {
+            if ($this->classExists($candidate)) {
+                return $candidate;
+            }
+        }
+
+        try {
+            require_once $file;
+        } catch (\Throwable $e) {
+            return null;
+        }
+
+        foreach ($candidates as $candidate) {
+            if ($this->classExists($candidate)) {
+                return $candidate;
+            }
+        }
+
+        return null;
+    }
+
+    private function classExists(string $class): bool
+    {
+        return class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false);
+    }
+}

src/Symfony/Component/ErrorHandler/FatalErrorHandler/FatalErrorHandlerInterface.php

@@ -0,0 +1,32 @@
+<?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\ErrorHandler\FatalErrorHandler;
+
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+
+/**
+ * Attempts to convert fatal errors to exceptions.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+interface FatalErrorHandlerInterface
+{
+    /**
+     * Attempts to convert an error into an exception.
+     *
+     * @param array               $error     An array as returned by error_get_last()
+     * @param FatalErrorException $exception A FatalErrorException instance
+     *
+     * @return FatalErrorException|null A FatalErrorException instance if the class is able to convert the error, null otherwise
+     */
+    public function handleError(array $error, FatalErrorException $exception);
+}

src/Symfony/Component/ErrorHandler/FatalErrorHandler/UndefinedFunctionFatalErrorHandler.php

@@ -0,0 +1,84 @@
+<?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\ErrorHandler\FatalErrorHandler;
+
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\Exception\UndefinedFunctionException;
+
+/**
+ * ErrorHandler for undefined functions.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class UndefinedFunctionFatalErrorHandler implements FatalErrorHandlerInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function handleError(array $error, FatalErrorException $exception)
+    {
+        $messageLen = \strlen($error['message']);
+        $notFoundSuffix = '()';
+        $notFoundSuffixLen = \strlen($notFoundSuffix);
+        if ($notFoundSuffixLen > $messageLen) {
+            return;
+        }
+
+        if (0 !== substr_compare($error['message'], $notFoundSuffix, -$notFoundSuffixLen)) {
+            return;
+        }
+
+        $prefix = 'Call to undefined function ';
+        $prefixLen = \strlen($prefix);
+        if (0 !== strpos($error['message'], $prefix)) {
+            return;
+        }
+
+        $fullyQualifiedFunctionName = substr($error['message'], $prefixLen, -$notFoundSuffixLen);
+        if (false !== $namespaceSeparatorIndex = strrpos($fullyQualifiedFunctionName, '\\')) {
+            $functionName = substr($fullyQualifiedFunctionName, $namespaceSeparatorIndex + 1);
+            $namespacePrefix = substr($fullyQualifiedFunctionName, 0, $namespaceSeparatorIndex);
+            $message = sprintf('Attempted to call function "%s" from namespace "%s".', $functionName, $namespacePrefix);
+        } else {
+            $functionName = $fullyQualifiedFunctionName;
+            $message = sprintf('Attempted to call function "%s" from the global namespace.', $functionName);
+        }
+
+        $candidates = [];
+        foreach (get_defined_functions() as $type => $definedFunctionNames) {
+            foreach ($definedFunctionNames as $definedFunctionName) {
+                if (false !== $namespaceSeparatorIndex = strrpos($definedFunctionName, '\\')) {
+                    $definedFunctionNameBasename = substr($definedFunctionName, $namespaceSeparatorIndex + 1);
+                } else {
+                    $definedFunctionNameBasename = $definedFunctionName;
+                }
+
+                if ($definedFunctionNameBasename === $functionName) {
+                    $candidates[] = '\\'.$definedFunctionName;
+                }
+            }
+        }
+
+        if ($candidates) {
+            sort($candidates);
+            $last = array_pop($candidates).'"?';
+            if ($candidates) {
+                $candidates = 'e.g. "'.implode('", "', $candidates).'" or "'.$last;
+            } else {
+                $candidates = '"'.$last;
+            }
+            $message .= "\nDid you mean to call ".$candidates;
+        }
+
+        return new UndefinedFunctionException($message, $exception);
+    }
+}

src/Symfony/Component/ErrorHandler/FatalErrorHandler/UndefinedMethodFatalErrorHandler.php

@@ -0,0 +1,66 @@
+<?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\ErrorHandler\FatalErrorHandler;
+
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\Exception\UndefinedMethodException;
+
+/**
+ * ErrorHandler for undefined methods.
+ *
+ * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ */
+class UndefinedMethodFatalErrorHandler implements FatalErrorHandlerInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function handleError(array $error, FatalErrorException $exception)
+    {
+        preg_match('/^Call to undefined method (.*)::(.*)\(\)$/', $error['message'], $matches);
+        if (!$matches) {
+            return;
+        }
+
+        $className = $matches[1];
+        $methodName = $matches[2];
+
+        $message = sprintf('Attempted to call an undefined method named "%s" of class "%s".', $methodName, $className);
+
+        if (!class_exists($className) || null === $methods = get_class_methods($className)) {
+            // failed to get the class or its methods on which an unknown method was called (for example on an anonymous class)
+            return new UndefinedMethodException($message, $exception);
+        }
+
+        $candidates = [];
+        foreach ($methods as $definedMethodName) {
+            $lev = levenshtein($methodName, $definedMethodName);
+            if ($lev <= \strlen($methodName) / 3 || false !== strpos($definedMethodName, $methodName)) {
+                $candidates[] = $definedMethodName;
+            }
+        }
+
+        if ($candidates) {
+            sort($candidates);
+            $last = array_pop($candidates).'"?';
+            if ($candidates) {
+                $candidates = 'e.g. "'.implode('", "', $candidates).'" or "'.$last;
+            } else {
+                $candidates = '"'.$last;
+            }
+
+            $message .= "\nDid you mean to call ".$candidates;
+        }
+
+        return new UndefinedMethodException($message, $exception);
+    }
+}

src/Symfony/Component/ErrorHandler/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2019 Fabien Potencier
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

src/Symfony/Component/ErrorHandler/README.md

@@ -0,0 +1,12 @@
+ErrorHandler Component
+======================
+
+The ErrorHandler component provides tools to manage and display errors and exceptions.
+
+Resources
+---------
+
+  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+  * [Report issues](https://github.com/symfony/symfony/issues) and
+    [send Pull Requests](https://github.com/symfony/symfony/pulls)
+    in the [main Symfony repository](https://github.com/symfony/symfony)

src/Symfony/Component/ErrorHandler/Tests/DependencyInjection/ErrorHandlerPassTest.php

@@ -0,0 +1,51 @@
+<?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\ErrorHandler\Tests\DependencyInjection;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Argument\ServiceClosureArgument;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\DependencyInjection\ServiceLocator;
+use Symfony\Component\ErrorHandler\DependencyInjection\ErrorHandlerPass;
+use Symfony\Component\ErrorHandler\DependencyInjection\ErrorRenderer;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorHandler\ErrorRenderer\JsonErrorRenderer;
+
+class ErrorHandlerPassTest extends TestCase
+{
+    public function testProcess()
+    {
+        $container = new ContainerBuilder();
+        $container->setParameter('kernel.debug', true);
+        $definition = $container->register('error_handler.error_renderer', ErrorRenderer::class)
+            ->addArgument([])
+        ;
+        $container->register('error_handler.renderer.html', HtmlErrorRenderer::class)
+            ->addTag('error_handler.renderer')
+        ;
+        $container->register('error_handler.renderer.json', JsonErrorRenderer::class)
+            ->addTag('error_handler.renderer')
+        ;
+
+        (new ErrorHandlerPass())->process($container);
+
+        $serviceLocatorDefinition = $container->getDefinition((string) $definition->getArgument(0));
+        $this->assertSame(ServiceLocator::class, $serviceLocatorDefinition->getClass());
+
+        $expected = [
+            'html' => new ServiceClosureArgument(new Reference('error_handler.renderer.html')),
+            'json' => new ServiceClosureArgument(new Reference('error_handler.renderer.json')),
+        ];
+        $this->assertEquals($expected, $serviceLocatorDefinition->getArgument(0));
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/DependencyInjection/ErrorRendererTest.php

@@ -0,0 +1,67 @@
+<?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\ErrorHandler\Tests\DependencyInjection;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorHandler\DependencyInjection\ErrorRenderer;
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRendererInterface;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+class ErrorRendererTest extends TestCase
+{
+    /**
+     * @expectedException \Symfony\Component\ErrorHandler\Exception\ErrorRendererNotFoundException
+     * @expectedExceptionMessage No error renderer found for format "foo".
+     */
+    public function testInvalidErrorRenderer()
+    {
+        $container = $this->getMockBuilder('Psr\Container\ContainerInterface')->getMock();
+        $container->expects($this->once())->method('has')->with('foo')->willReturn(false);
+
+        $exception = FlattenException::create(new \Exception('Foo'));
+        (new ErrorRenderer($container))->render($exception, 'foo');
+    }
+
+    public function testCustomErrorRenderer()
+    {
+        $container = $this->getMockBuilder('Psr\Container\ContainerInterface')->getMock();
+        $container
+            ->expects($this->once())
+            ->method('has')
+            ->with('foo')
+            ->willReturn(true)
+        ;
+        $container
+            ->expects($this->once())
+            ->method('get')
+            ->willReturn(new FooErrorRenderer())
+        ;
+
+        $errorRenderer = new ErrorRenderer($container);
+
+        $exception = FlattenException::create(new \RuntimeException('Foo'));
+        $this->assertSame('Foo', $errorRenderer->render($exception, 'foo'));
+    }
+}
+
+class FooErrorRenderer implements ErrorRendererInterface
+{
+    public static function getFormat(): string
+    {
+        return 'foo';
+    }
+
+    public function render(FlattenException $exception): string
+    {
+        return $exception->getMessage();
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/ErrorHandlerTest.php

@@ -9,16 +9,16 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests;
+namespace Symfony\Component\ErrorHandler\Tests;
 
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LogLevel;
 use Psr\Log\NullLogger;
-use Symfony\Component\Debug\BufferingLogger;
-use Symfony\Component\Debug\ErrorHandler;
-use Symfony\Component\Debug\Exception\SilencedErrorContext;
-use Symfony\Component\Debug\Tests\Fixtures\ErrorHandlerThatUsesThePreviousOne;
-use Symfony\Component\Debug\Tests\Fixtures\LoggerThatSetAnErrorHandler;
+use Symfony\Component\ErrorHandler\BufferingLogger;
+use Symfony\Component\ErrorHandler\ErrorHandler;
+use Symfony\Component\ErrorHandler\Exception\SilencedErrorContext;
+use Symfony\Component\ErrorHandler\Tests\Fixtures\ErrorHandlerThatUsesThePreviousOne;
+use Symfony\Component\ErrorHandler\Tests\Fixtures\LoggerThatSetAnErrorHandler;
 
 /**
  * ErrorHandlerTest.
@@ -33,7 +33,7 @@ class ErrorHandlerTest extends TestCase
         $handler = ErrorHandler::register();
 
         try {
-            $this->assertInstanceOf('Symfony\Component\Debug\ErrorHandler', $handler);
+            $this->assertInstanceOf('Symfony\Component\ErrorHandler\ErrorHandler', $handler);
             $this->assertSame($handler, ErrorHandler::register());
 
             $newHandler = new ErrorHandler();
@@ -151,21 +151,21 @@ class ErrorHandlerTest extends TestCase
             $handler->setDefaultLogger($logger, [E_USER_NOTICE => LogLevel::CRITICAL]);
 
             $loggers = [
-                E_DEPRECATED => [null, LogLevel::INFO],
-                E_USER_DEPRECATED => [null, LogLevel::INFO],
-                E_NOTICE => [$logger, LogLevel::WARNING],
-                E_USER_NOTICE => [$logger, LogLevel::CRITICAL],
-                E_STRICT => [null, LogLevel::WARNING],
-                E_WARNING => [null, LogLevel::WARNING],
-                E_USER_WARNING => [null, LogLevel::WARNING],
-                E_COMPILE_WARNING => [null, LogLevel::WARNING],
-                E_CORE_WARNING => [null, LogLevel::WARNING],
-                E_USER_ERROR => [null, LogLevel::CRITICAL],
-                E_RECOVERABLE_ERROR => [null, LogLevel::CRITICAL],
                 E_COMPILE_ERROR => [null, LogLevel::CRITICAL],
-                E_PARSE => [null, LogLevel::CRITICAL],
-                E_ERROR => [null, LogLevel::CRITICAL],
+                E_COMPILE_WARNING => [null, LogLevel::WARNING],
                 E_CORE_ERROR => [null, LogLevel::CRITICAL],
+                E_CORE_WARNING => [null, LogLevel::WARNING],
+                E_DEPRECATED => [null, LogLevel::INFO],
+                E_ERROR => [null, LogLevel::CRITICAL],
+                E_NOTICE => [$logger, LogLevel::WARNING],
+                E_PARSE => [null, LogLevel::CRITICAL],
+                E_RECOVERABLE_ERROR => [null, LogLevel::CRITICAL],
+                E_STRICT => [null, LogLevel::WARNING],
+                E_USER_DEPRECATED => [null, LogLevel::INFO],
+                E_USER_ERROR => [null, LogLevel::CRITICAL],
+                E_USER_NOTICE => [$logger, LogLevel::CRITICAL],
+                E_USER_WARNING => [null, LogLevel::WARNING],
+                E_WARNING => [null, LogLevel::WARNING],
             ];
             $this->assertSame($loggers, $handler->setLoggers([]));
         } finally {
@@ -375,21 +375,21 @@ class ErrorHandlerTest extends TestCase
         $handler = new ErrorHandler($bootLogger);
 
         $loggers = [
-            E_DEPRECATED => [$bootLogger, LogLevel::INFO],
-            E_USER_DEPRECATED => [$bootLogger, LogLevel::INFO],
-            E_NOTICE => [$bootLogger, LogLevel::WARNING],
-            E_USER_NOTICE => [$bootLogger, LogLevel::WARNING],
-            E_STRICT => [$bootLogger, LogLevel::WARNING],
-            E_WARNING => [$bootLogger, LogLevel::WARNING],
-            E_USER_WARNING => [$bootLogger, LogLevel::WARNING],
-            E_COMPILE_WARNING => [$bootLogger, LogLevel::WARNING],
-            E_CORE_WARNING => [$bootLogger, LogLevel::WARNING],
-            E_USER_ERROR => [$bootLogger, LogLevel::CRITICAL],
-            E_RECOVERABLE_ERROR => [$bootLogger, LogLevel::CRITICAL],
             E_COMPILE_ERROR => [$bootLogger, LogLevel::CRITICAL],
-            E_PARSE => [$bootLogger, LogLevel::CRITICAL],
-            E_ERROR => [$bootLogger, LogLevel::CRITICAL],
+            E_COMPILE_WARNING => [$bootLogger, LogLevel::WARNING],
             E_CORE_ERROR => [$bootLogger, LogLevel::CRITICAL],
+            E_CORE_WARNING => [$bootLogger, LogLevel::WARNING],
+            E_DEPRECATED => [$bootLogger, LogLevel::INFO],
+            E_ERROR => [$bootLogger, LogLevel::CRITICAL],
+            E_NOTICE => [$bootLogger, LogLevel::WARNING],
+            E_PARSE => [$bootLogger, LogLevel::CRITICAL],
+            E_RECOVERABLE_ERROR => [$bootLogger, LogLevel::CRITICAL],
+            E_STRICT => [$bootLogger, LogLevel::WARNING],
+            E_USER_DEPRECATED => [$bootLogger, LogLevel::INFO],
+            E_USER_ERROR => [$bootLogger, LogLevel::CRITICAL],
+            E_USER_NOTICE => [$bootLogger, LogLevel::WARNING],
+            E_USER_WARNING => [$bootLogger, LogLevel::WARNING],
+            E_WARNING => [$bootLogger, LogLevel::WARNING],
         ];
 
         $this->assertSame($loggers, $handler->setLoggers([]));
@@ -490,7 +490,7 @@ class ErrorHandlerTest extends TestCase
 
         $handler->handleException($exception);
 
-        $this->assertInstanceOf('Symfony\Component\Debug\Exception\ClassNotFoundException', $args[0]);
+        $this->assertInstanceOf('Symfony\Component\ErrorHandler\Exception\ClassNotFoundException', $args[0]);
         $this->assertStringStartsWith("Attempted to load class \"IReallyReallyDoNotExistAnywhereInTheRepositoryISwear\" from the global namespace.\nDid you forget a \"use\" statement", $args[0]->getMessage());
     }
 

src/Symfony/Component/ErrorHandler/Tests/ErrorRenderer/ErrorRendererTest.php

@@ -0,0 +1,62 @@
+<?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\ErrorHandler\Tests\ErrorRenderer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRenderer;
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRendererInterface;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+class ErrorRendererTest extends TestCase
+{
+    /**
+     * @expectedException \Symfony\Component\ErrorHandler\Exception\ErrorRendererNotFoundException
+     * @expectedExceptionMessage No error renderer found for format "foo".
+     */
+    public function testErrorRendererNotFound()
+    {
+        $exception = FlattenException::create(new \Exception('foo'));
+        (new ErrorRenderer([]))->render($exception, 'foo');
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Error renderer "stdClass" must implement "Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRendererInterface".
+     */
+    public function testInvalidErrorRenderer()
+    {
+        $exception = FlattenException::create(new \Exception('foo'));
+        (new ErrorRenderer([new \stdClass()]))->render($exception, 'foo');
+    }
+
+    public function testCustomErrorRenderer()
+    {
+        $renderers = [new FooErrorRenderer()];
+        $errorRenderer = new ErrorRenderer($renderers);
+
+        $exception = FlattenException::create(new \RuntimeException('Foo'));
+        $this->assertSame('Foo', $errorRenderer->render($exception, 'foo'));
+    }
+}
+
+class FooErrorRenderer implements ErrorRendererInterface
+{
+    public static function getFormat(): string
+    {
+        return 'foo';
+    }
+
+    public function render(FlattenException $exception): string
+    {
+        return $exception->getMessage();
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/ErrorRenderer/HtmlErrorRendererTest.php

@@ -0,0 +1,27 @@
+<?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\ErrorHandler\Tests\ErrorRenderer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+class HtmlErrorRendererTest extends TestCase
+{
+    public function testRender()
+    {
+        $exception = FlattenException::create(new \RuntimeException('Foo'));
+        $expected = '<!DOCTYPE html>%A<html>%A<head>%A<title>Internal Server Error</title>%A<h1 class="break-long-words exception-message">Foo</h1>%A<abbr title="RuntimeException">RuntimeException</abbr>%A';
+
+        $this->assertStringMatchesFormat($expected, (new HtmlErrorRenderer())->render($exception));
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/ErrorRenderer/JsonErrorRendererTest.php

@@ -0,0 +1,27 @@
+<?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\ErrorHandler\Tests\ErrorRenderer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorHandler\ErrorRenderer\JsonErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+class JsonErrorRendererTest extends TestCase
+{
+    public function testRender()
+    {
+        $exception = FlattenException::create(new \RuntimeException('Foo'));
+        $expected = '{"title":"Internal Server Error","status":500,"detail":"Foo","exceptions":[{"message":"Foo","class":"RuntimeException","trace":';
+
+        $this->assertStringStartsWith($expected, (new JsonErrorRenderer())->render($exception));
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/ErrorRenderer/TxtErrorRendererTest.php

@@ -0,0 +1,27 @@
+<?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\ErrorHandler\Tests\ErrorRenderer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorHandler\ErrorRenderer\TxtErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+class TxtErrorRendererTest extends TestCase
+{
+    public function testRender()
+    {
+        $exception = FlattenException::create(new \RuntimeException('Foo'));
+        $expected = '[title] Internal Server Error%A[status] 500%A[detail] Foo%A[1] RuntimeException: Foo%A';
+
+        $this->assertStringMatchesFormat($expected, (new TxtErrorRenderer())->render($exception));
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/ErrorRenderer/XmlErrorRendererTest.php

@@ -0,0 +1,27 @@
+<?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\ErrorHandler\Tests\ErrorRenderer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\ErrorHandler\ErrorRenderer\XmlErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
+
+class XmlErrorRendererTest extends TestCase
+{
+    public function testRender()
+    {
+        $exception = FlattenException::create(new \RuntimeException('Foo'));
+        $expected = '<?xml version="1.0" encoding="UTF-8" ?>%A<problem xmlns="urn:ietf:rfc:7807">%A<title>Internal Server Error</title>%A<status>500</status>%A<detail>Foo</detail>%A';
+
+        $this->assertStringMatchesFormat($expected, (new XmlErrorRenderer())->render($exception));
+    }
+}

src/Symfony/Component/ErrorHandler/Tests/Exception/FlattenExceptionTest.php

@@ -9,11 +9,11 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests\Exception;
+namespace Symfony\Component\ErrorHandler\Tests\Exception;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Debug\Exception\FatalThrowableError;
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FatalThrowableError;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Exception\SuspiciousOperationException;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;

src/Symfony/Component/ErrorHandler/Tests/ExceptionHandlerTest.php

@@ -9,11 +9,11 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests;
+namespace Symfony\Component\ErrorHandler\Tests;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Debug\Exception\OutOfMemoryException;
-use Symfony\Component\Debug\ExceptionHandler;
+use Symfony\Component\ErrorHandler\Exception\OutOfMemoryException;
+use Symfony\Component\ErrorHandler\ExceptionHandler;
 use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 
@@ -39,7 +39,7 @@ class ExceptionHandlerTest extends TestCase
         $handler->sendPhpResponse(new \RuntimeException('Foo'));
         $response = ob_get_clean();
 
-        $this->assertContains('Whoops, looks like something went wrong.', $response);
+        $this->assertContains('The server returned a "500 Internal Server Error".', $response);
         $this->assertNotContains('<div class="trace trace-as-html">', $response);
 
         $handler = new ExceptionHandler(true);
@@ -69,7 +69,7 @@ content="0;url=data:text/html;base64,PHNjcmlwdD5hbGVydCgndGVzdDMnKTwvc2NyaXB0Pg"
         $handler->sendPhpResponse(new NotFoundHttpException('Foo'));
         $response = ob_get_clean();
 
-        $this->assertContains('Sorry, the page you are looking for could not be found.', $response);
+        $this->assertContains('The server returned a "404 Not Found".', $response);
 
         $expectedHeaders = [
             ['HTTP/1.0 404', true, null],
@@ -110,7 +110,7 @@ content="0;url=data:text/html;base64,PHNjcmlwdD5hbGVydCgndGVzdDMnKTwvc2NyaXB0Pg"
     {
         $exception = new \Exception('foo');
 
-        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
+        $handler = $this->getMockBuilder('Symfony\Component\ErrorHandler\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
         $handler
             ->expects($this->exactly(2))
             ->method('sendPhpResponse');
@@ -128,7 +128,7 @@ content="0;url=data:text/html;base64,PHNjcmlwdD5hbGVydCgndGVzdDMnKTwvc2NyaXB0Pg"
     {
         $exception = new OutOfMemoryException('foo', 0, E_ERROR, __FILE__, __LINE__);
 
-        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
+        $handler = $this->getMockBuilder('Symfony\Component\ErrorHandler\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
         $handler
             ->expects($this->once())
             ->method('sendPhpResponse');

src/Symfony/Component/ErrorHandler/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php

@@ -9,13 +9,13 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests\FatalErrorHandler;
+namespace Symfony\Component\ErrorHandler\Tests\FatalErrorHandler;
 
 use Composer\Autoload\ClassLoader as ComposerClassLoader;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Debug\DebugClassLoader;
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
 
 class ClassNotFoundFatalErrorHandlerTest extends TestCase
 {
@@ -32,7 +32,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
             }
 
             if ($function[0] instanceof ComposerClassLoader) {
-                $function[0]->add('Symfony_Component_Debug_Tests_Fixtures', \dirname(\dirname(\dirname(\dirname(\dirname(__DIR__))))));
+                $function[0]->add('Symfony_Component_ErrorHandler_Tests_Fixtures', \dirname(\dirname(\dirname(\dirname(\dirname(__DIR__))))));
                 break;
             }
         }
@@ -60,7 +60,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
             array_map('spl_autoload_register', $autoloaders);
         }
 
-        $this->assertInstanceOf('Symfony\Component\Debug\Exception\ClassNotFoundException', $exception);
+        $this->assertInstanceOf('Symfony\Component\ErrorHandler\Exception\ClassNotFoundException', $exception);
         $this->assertSame($translatedMessage, $exception->getMessage());
         $this->assertSame($error['type'], $exception->getSeverity());
         $this->assertSame($error['file'], $exception->getFile());
@@ -70,7 +70,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
     public function provideClassNotFoundData()
     {
         $autoloader = new ComposerClassLoader();
-        $autoloader->add('Symfony\Component\Debug\Exception\\', realpath(__DIR__.'/../../Exception'));
+        $autoloader->add('Symfony\Component\ErrorHandler\Exception\\', realpath(__DIR__.'/../../Exception'));
 
         $debugClassLoader = new DebugClassLoader([$autoloader, 'loadClass']);
 
@@ -98,9 +98,9 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                     'type' => 1,
                     'line' => 12,
                     'file' => 'foo.php',
-                    'message' => 'Class \'UndefinedFunctionException\' not found',
+                    'message' => 'Class \'UndefinedFuncException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "Attempted to load class \"UndefinedFuncException\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony\Component\ErrorHandler\Tests\Fixtures\UndefinedFuncException\"?",
             ],
             [
                 [
@@ -109,7 +109,16 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                     'file' => 'foo.php',
                     'message' => 'Class \'PEARClass\' not found',
                 ],
-                "Attempted to load class \"PEARClass\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony_Component_Debug_Tests_Fixtures_PEARClass\"?",
+                "Attempted to load class \"PEARClass\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony_Component_ErrorHandler_Tests_Fixtures_PEARClass\"?",
+            ],
+            [
+                [
+                    'type' => 1,
+                    'line' => 12,
+                    'file' => 'foo.php',
+                    'message' => 'Class \'Foo\\Bar\\UndefinedFuncException\' not found',
+                ],
+                "Attempted to load class \"UndefinedFuncException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\ErrorHandler\Tests\Fixtures\UndefinedFuncException\"?",
             ],
             [
                 [
@@ -118,16 +127,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
-            ],
-            [
-                [
-                    'type' => 1,
-                    'line' => 12,
-                    'file' => 'foo.php',
-                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
-                ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\ErrorHandler\Exception\UndefinedFunctionException\"?",
                 [$autoloader, 'loadClass'],
             ],
             [
@@ -137,7 +137,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\ErrorHandler\Exception\UndefinedFunctionException\"?",
                 [$debugClassLoader, 'loadClass'],
             ],
             [
@@ -171,6 +171,6 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
         $handler = new ClassNotFoundFatalErrorHandler();
         $exception = $handler->handleError($error, new FatalErrorException('', 0, $error['type'], $error['file'], $error['line']));
 
-        $this->assertInstanceOf('Symfony\Component\Debug\Exception\ClassNotFoundException', $exception);
+        $this->assertInstanceOf('Symfony\Component\ErrorHandler\Exception\ClassNotFoundException', $exception);
     }
 }

src/Symfony/Component/ErrorHandler/Tests/FatalErrorHandler/UndefinedFunctionFatalErrorHandlerTest.php

@@ -9,11 +9,11 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests\FatalErrorHandler;
+namespace Symfony\Component\ErrorHandler\Tests\FatalErrorHandler;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
 
 class UndefinedFunctionFatalErrorHandlerTest extends TestCase
 {
@@ -25,7 +25,7 @@ class UndefinedFunctionFatalErrorHandlerTest extends TestCase
         $handler = new UndefinedFunctionFatalErrorHandler();
         $exception = $handler->handleError($error, new FatalErrorException('', 0, $error['type'], $error['file'], $error['line']));
 
-        $this->assertInstanceOf('Symfony\Component\Debug\Exception\UndefinedFunctionException', $exception);
+        $this->assertInstanceOf('Symfony\Component\ErrorHandler\Exception\UndefinedFunctionException', $exception);
         // class names are case insensitive and PHP do not return the same
         $this->assertSame(strtolower($translatedMessage), strtolower($exception->getMessage()));
         $this->assertSame($error['type'], $exception->getSeverity());
@@ -43,7 +43,7 @@ class UndefinedFunctionFatalErrorHandlerTest extends TestCase
                     'file' => 'foo.php',
                     'message' => 'Call to undefined function test_namespaced_function()',
                 ],
-                "Attempted to call function \"test_namespaced_function\" from the global namespace.\nDid you mean to call \"\\symfony\\component\\debug\\tests\\fatalerrorhandler\\test_namespaced_function\"?",
+                "Attempted to call function \"test_namespaced_function\" from the global namespace.\nDid you mean to call \"\\symfony\\component\\errorhandler\\tests\\fatalerrorhandler\\test_namespaced_function\"?",
             ],
             [
                 [
@@ -52,7 +52,7 @@ class UndefinedFunctionFatalErrorHandlerTest extends TestCase
                     'file' => 'foo.php',
                     'message' => 'Call to undefined function Foo\\Bar\\Baz\\test_namespaced_function()',
                 ],
-                "Attempted to call function \"test_namespaced_function\" from namespace \"Foo\\Bar\\Baz\".\nDid you mean to call \"\\symfony\\component\\debug\\tests\\fatalerrorhandler\\test_namespaced_function\"?",
+                "Attempted to call function \"test_namespaced_function\" from namespace \"Foo\\Bar\\Baz\".\nDid you mean to call \"\\symfony\\component\\errorhandler\\tests\\fatalerrorhandler\\test_namespaced_function\"?",
             ],
             [
                 [

src/Symfony/Component/ErrorHandler/Tests/FatalErrorHandler/UndefinedMethodFatalErrorHandlerTest.php

@@ -9,11 +9,11 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests\FatalErrorHandler;
+namespace Symfony\Component\ErrorHandler\Tests\FatalErrorHandler;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;
+use Symfony\Component\ErrorHandler\Exception\FatalErrorException;
+use Symfony\Component\ErrorHandler\FatalErrorHandler\UndefinedMethodFatalErrorHandler;
 
 class UndefinedMethodFatalErrorHandlerTest extends TestCase
 {
@@ -25,7 +25,7 @@ class UndefinedMethodFatalErrorHandlerTest extends TestCase
         $handler = new UndefinedMethodFatalErrorHandler();
         $exception = $handler->handleError($error, new FatalErrorException('', 0, $error['type'], $error['file'], $error['line']));
 
-        $this->assertInstanceOf('Symfony\Component\Debug\Exception\UndefinedMethodException', $exception);
+        $this->assertInstanceOf('Symfony\Component\ErrorHandler\Exception\UndefinedMethodException', $exception);
         $this->assertSame($translatedMessage, $exception->getMessage());
         $this->assertSame($error['type'], $exception->getSeverity());
         $this->assertSame($error['file'], $exception->getFile());

src/Symfony/Component/ErrorHandler/Tests/Fixtures/ErrorHandlerThatUsesThePreviousOne.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace Symfony\Component\Debug\Tests\Fixtures;
+namespace Symfony\Component\ErrorHandler\Tests\Fixtures;
 
 class ErrorHandlerThatUsesThePreviousOne
 {

src/Symfony/Component/ErrorHandler/Tests/Fixtures/LoggerThatSetAnErrorHandler.php

@@ -1,8 +1,8 @@
 <?php
 
-namespace Symfony\Component\Debug\Tests\Fixtures;
+namespace Symfony\Component\ErrorHandler\Tests\Fixtures;
 
-use Symfony\Component\Debug\BufferingLogger;
+use Symfony\Component\ErrorHandler\BufferingLogger;
 
 class LoggerThatSetAnErrorHandler extends BufferingLogger
 {

src/Symfony/Component/ErrorHandler/Tests/Fixtures/PEARClass.php

@@ -0,0 +1,5 @@
+<?php
+
+class Symfony_Component_ErrorHandler_Tests_Fixtures_PEARClass
+{
+}

src/Symfony/Component/ErrorHandler/Tests/Fixtures/ToStringThrower.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace Symfony\Component\Debug\Tests\Fixtures;
+namespace Symfony\Component\ErrorHandler\Tests\Fixtures;
 
 class ToStringThrower
 {

src/Symfony/Component/ErrorHandler/Tests/Fixtures/UndefinedFuncException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Symfony\Component\ErrorHandler\Tests\Fixtures;
+
+class UndefinedFuncException
+{
+}

src/Symfony/Component/ErrorHandler/Tests/HeaderMock.php

@@ -9,7 +9,7 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug;
+namespace Symfony\Component\ErrorHandler;
 
 function headers_sent()
 {
@@ -21,7 +21,7 @@ function header($str, $replace = true, $status = null)
     Tests\testHeader($str, $replace, $status);
 }
 
-namespace Symfony\Component\Debug\Tests;
+namespace Symfony\Component\ErrorHandler\Tests;
 
 function testHeader()
 {

src/Symfony/Component/ErrorHandler/Tests/MockExceptionHandler.php

@@ -9,9 +9,9 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Debug\Tests;
+namespace Symfony\Component\ErrorHandler\Tests;
 
-use Symfony\Component\Debug\ExceptionHandler;
+use Symfony\Component\ErrorHandler\ExceptionHandler;
 
 class MockExceptionHandler extends ExceptionHandler
 {

src/Symfony/Component/ErrorHandler/Tests/phpt/decorate_exception_hander.phpt

@@ -5,7 +5,7 @@ display_errors=0
 --FILE--
 <?php
 
-namespace Symfony\Component\Debug;
+namespace Symfony\Component\ErrorHandler;
 
 $vendor = __DIR__;
 while (!file_exists($vendor.'/vendor')) {
@@ -26,9 +26,9 @@ if (true) {
 
 ?>
 --EXPECTF--
-object(Symfony\Component\Debug\Exception\ClassNotFoundException)#%d (8) {
+object(Symfony\Component\ErrorHandler\Exception\ClassNotFoundException)#%d (8) {
   ["message":protected]=>
-  string(131) "Attempted to load class "missing" from namespace "Symfony\Component\Debug".
+  string(138) "Attempted to load class "missing" from namespace "Symfony\Component\ErrorHandler".
 Did you forget a "use" statement for another namespace?"
   ["string":"Exception":private]=>
   string(0) ""

src/Symfony/Component/ErrorHandler/Tests/phpt/exception_rethrown.phpt

@@ -3,7 +3,7 @@ Test rethrowing in custom exception handler
 --FILE--
 <?php
 
-namespace Symfony\Component\Debug;
+namespace Symfony\Component\ErrorHandler;
 
 $vendor = __DIR__;
 while (!file_exists($vendor.'/vendor')) {

src/Symfony/Component/ErrorHandler/Tests/phpt/fatal_with_nested_handlers.phpt

@@ -3,7 +3,9 @@ Test catching fatal errors when handlers are nested
 --FILE--
 <?php
 
-namespace Symfony\Component\Debug;
+namespace Symfony\Component\ErrorHandler;
+
+use Symfony\Component\Debug\Debug;
 
 $vendor = __DIR__;
 while (!file_exists($vendor.'/vendor')) {
@@ -35,8 +37,8 @@ array(1) {
   [0]=>
   string(37) "Error and exception handlers do match"
 }
-object(Symfony\Component\Debug\Exception\FatalErrorException)#%d (%d) {
+object(Symfony\Component\ErrorHandler\Exception\FatalErrorException)#%d (%d) {
   ["message":protected]=>
-  string(179) "Error: Class Symfony\Component\Debug\Broken contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (JsonSerializable::jsonSerialize)"
+  string(186) "Error: Class Symfony\Component\ErrorHandler\Broken contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (JsonSerializable::jsonSerialize)"
 %a
 }

src/Symfony/Component/ErrorHandler/composer.json

@@ -0,0 +1,42 @@
+{
+    "name": "symfony/error-handler",
+    "type": "library",
+    "description": "Symfony ErrorHandler Component",
+    "keywords": [],
+    "homepage": "https://symfony.com",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Fabien Potencier",
+            "email": "fabien@symfony.com"
+        },
+        {
+            "name": "Symfony Community",
+            "homepage": "https://symfony.com/contributors"
+        }
+    ],
+    "require": {
+        "php": "^7.1.3",
+        "psr/log": "~1.0"
+    },
+    "require-dev": {
+        "symfony/debug": "^4.4",
+        "symfony/dependency-injection": "^4.4",
+        "symfony/http-kernel": "^4.4"
+    },
+    "conflict": {
+        "symfony/http-kernel": "<4.4"
+    },
+    "autoload": {
+        "psr-4": { "Symfony\\Component\\ErrorHandler\\": "" },
+        "exclude-from-classmap": [
+            "/Tests/"
+        ]
+    },
+    "minimum-stability": "dev",
+    "extra": {
+        "branch-alias": {
+            "dev-master": "4.4-dev"
+        }
+    }
+}

src/Symfony/Component/ErrorHandler/phpunit.xml.dist

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/5.2/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <php>
+        <ini name="error_reporting" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Symfony ErrorHandler Component Test Suite">
+            <directory>./Tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./</directory>
+            <exclude>
+                <directory>./Tests</directory>
+                <directory>./vendor</directory>
+            </exclude>
+        </whitelist>
+    </filter>
+</phpunit>

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

@@ -11,7 +11,7 @@
 
 namespace Symfony\Component\HttpKernel\DataCollector;
 
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 

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

@@ -11,7 +11,7 @@
 
 namespace Symfony\Component\HttpKernel\DataCollector;
 
-use Symfony\Component\Debug\Exception\SilencedErrorContext;
+use Symfony\Component\ErrorHandler\Exception\SilencedErrorContext;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;
 use Symfony\Component\HttpFoundation\Response;

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

@@ -15,8 +15,11 @@ use Psr\Log\LoggerInterface;
 use Symfony\Component\Console\ConsoleEvents;
 use Symfony\Component\Console\Event\ConsoleEvent;
 use Symfony\Component\Console\Output\ConsoleOutputInterface;
-use Symfony\Component\Debug\ErrorHandler;
-use Symfony\Component\Debug\ExceptionHandler;
+use Symfony\Component\ErrorHandler\ErrorHandler;
+use Symfony\Component\ErrorHandler\ErrorRenderer\ErrorRenderer;
+use Symfony\Component\ErrorHandler\ErrorRenderer\HtmlErrorRenderer;
+use Symfony\Component\ErrorHandler\Exception\ErrorRendererNotFoundException;
+use Symfony\Component\ErrorHandler\ExceptionHandler;
 use Symfony\Component\EventDispatcher\Event;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpFoundation\Request;
@@ -43,6 +46,7 @@ class DebugHandlersListener implements EventSubscriberInterface
     private $fileLinkFormat;
     private $scope;
     private $charset;
+    private $errorRenderer;
     private $firstCall = true;
     private $hasTerminatedWithException;
 
@@ -55,7 +59,7 @@ class DebugHandlersListener implements EventSubscriberInterface
      * @param string|FileLinkFormatter|null $fileLinkFormat   The format for links to source files
      * @param bool                          $scope            Enables/disables scoping mode
      */
-    public function __construct(callable $exceptionHandler = null, LoggerInterface $logger = null, $levels = E_ALL, ?int $throwAt = E_ALL, bool $scream = true, $fileLinkFormat = null, bool $scope = true, string $charset = null)
+    public function __construct(callable $exceptionHandler = null, LoggerInterface $logger = null, $levels = E_ALL, ?int $throwAt = E_ALL, bool $scream = true, $fileLinkFormat = null, bool $scope = true, string $charset = null, ErrorRenderer $errorRenderer = null)
     {
         $this->exceptionHandler = $exceptionHandler;
         $this->logger = $logger;
@@ -65,6 +69,7 @@ class DebugHandlersListener implements EventSubscriberInterface
         $this->fileLinkFormat = $fileLinkFormat;
         $this->scope = $scope;
         $this->charset = $charset;
+        $this->errorRenderer = $errorRenderer;
     }
 
     /**
@@ -162,10 +167,17 @@ class DebugHandlersListener implements EventSubscriberInterface
 
         $debug = $this->scream && $this->scope;
         $controller = function (Request $request) use ($debug) {
-            $e = $request->attributes->get('exception');
-            $handler = new ExceptionHandler($debug, $this->charset, $this->fileLinkFormat);
+            if (null === $this->errorRenderer) {
+                $this->errorRenderer = new ErrorRenderer([new HtmlErrorRenderer($debug, $this->charset, $this->fileLinkFormat)]);
+            }
 
-            return new Response($handler->getHtml($e), $e->getStatusCode(), $e->getHeaders());
+            $e = $request->attributes->get('exception');
+
+            try {
+                return new Response($this->errorRenderer->render($e, $request->getRequestFormat()), $e->getStatusCode(), $e->getHeaders());
+            } catch (ErrorRendererNotFoundException $_) {
+                return new Response($this->errorRenderer->render($e), $e->getStatusCode(), $e->getHeaders());
+            }
         };
 
         (new ExceptionListener($controller, $this->logger, $debug))->onKernelException($event);

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

@@ -12,11 +12,10 @@
 namespace Symfony\Component\HttpKernel\EventListener;
 
 use Psr\Log\LoggerInterface;
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
 use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
 use Symfony\Component\HttpKernel\HttpKernelInterface;

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

@@ -12,7 +12,7 @@
 namespace Symfony\Component\HttpKernel\Tests\DataCollector;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\DataCollector\ExceptionDataCollector;

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

@@ -12,7 +12,7 @@
 namespace Symfony\Component\HttpKernel\Tests\DataCollector;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Debug\Exception\SilencedErrorContext;
+use Symfony\Component\ErrorHandler\Exception\SilencedErrorContext;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;
 use Symfony\Component\HttpFoundation\Response;
@@ -106,7 +106,7 @@ class LoggerDataCollectorTest extends TestCase
         $logs = array_map(function ($v) {
             if (isset($v['context']['exception'])) {
                 $e = &$v['context']['exception'];
-                $e = isset($e["\0*\0message"]) ? [$e["\0*\0message"], $e["\0*\0severity"]] : [$e["\0Symfony\Component\Debug\Exception\SilencedErrorContext\0severity"]];
+                $e = isset($e["\0*\0message"]) ? [$e["\0*\0message"], $e["\0*\0severity"]] : [$e["\0Symfony\Component\ErrorHandler\Exception\SilencedErrorContext\0severity"]];
             }
 
             return $v;

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

@@ -19,8 +19,8 @@ use Symfony\Component\Console\Event\ConsoleEvent;
 use Symfony\Component\Console\Helper\HelperSet;
 use Symfony\Component\Console\Input\ArgvInput;
 use Symfony\Component\Console\Output\ConsoleOutput;
-use Symfony\Component\Debug\ErrorHandler;
-use Symfony\Component\Debug\ExceptionHandler;
+use Symfony\Component\ErrorHandler\ErrorHandler;
+use Symfony\Component\ErrorHandler\ExceptionHandler;
 use Symfony\Component\EventDispatcher\EventDispatcher;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Event\KernelEvent;

src/Symfony/Component/HttpKernel/composer.json

@@ -17,9 +17,10 @@
     ],
     "require": {
         "php": "^7.1.3",
+        "symfony/error-handler": "^4.4",
         "symfony/event-dispatcher": "^4.3",
         "symfony/http-foundation": "^4.4|^5.0",
-        "symfony/debug": "^3.4|^4.0|^5.0",
+        "symfony/debug": "^4.4|^5.0",
         "symfony/polyfill-ctype": "^1.8",
         "symfony/polyfill-php73": "^1.9",
         "psr/log": "~1.0"

src/Symfony/Component/Messenger/EventListener/SendFailedMessageToFailureTransportListener.php

@@ -11,7 +11,7 @@
 namespace Symfony\Component\Messenger\EventListener;
 
 use Psr\Log\LoggerInterface;
-use Symfony\Component\Debug\Exception\FlattenException;
+use Symfony\Component\ErrorHandler\Exception\FlattenException;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\Messenger\Event\WorkerMessageFailedEvent;
 use Symfony\Component\Messenger\Exception\HandlerFailedException;