Fixed the DebugClassLoader compatibility with eval()'d code on Darwin

Apply php-cs-fixer rule for array_key_exists()
[Debug][ErrorHandler] Preserve next error handler
2026-03-25 01:32:09 +01:00 · 2019-02-24 16:45:11 +01:00 · 2019-02-23 16:06:07 +01:00 · 2019-02-16 11:38:56 +01:00 · 2019-01-25 11:19:25 +01:00 · 2019-01-24 21:41:57 +01:00
54 changed files with 1738 additions and 741 deletions
--- a/BufferingLogger.php
+++ b/BufferingLogger.php
@@ -20,17 +20,17 @@ use Psr\Log\AbstractLogger;
 */
 class BufferingLogger extends AbstractLogger
 {
-    private $logs = array();
+    private $logs = [];

-    public function log($level, $message, array $context = array())
+    public function log($level, $message, array $context = [])
    {
-        $this->logs[] = array($level, $message, $context);
+        $this->logs[] = [$level, $message, $context];
    }

    public function cleanLogs()
    {
        $logs = $this->logs;
-        $this->logs = array();
+        $this->logs = [];

        return $logs;
    }
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,16 @@
 CHANGELOG
 =========

+3.4.0
+-----
+
+* deprecated `ErrorHandler::stackErrors()` and `ErrorHandler::unstackErrors()`
+
+3.3.0
+-----
+
+* deprecated the `ContextErrorException` class: use \ErrorException directly now
+
 3.2.0
 -----

--- a/Debug.php
+++ b/Debug.php
@@ -23,10 +23,7 @@ class Debug
    /**
     * Enables the debug tools.
     *
-     * This method registers an error handler and an exception handler.
-     *
-     * If the Symfony ClassLoader component is available, a special
-     * class loader is also registered.
+     * This method registers an error handler, an exception handler and a special class loader.
     *
     * @param int  $errorReportingLevel The level of error reporting you want
     * @param bool $displayErrors       Whether to display errors (for development) or just log them (for production)
@@ -45,10 +42,10 @@ class Debug
            error_reporting(E_ALL);
        }

-        if ('cli' !== PHP_SAPI) {
+        if (!\in_array(\PHP_SAPI, ['cli', 'phpdbg'], true)) {
            ini_set('display_errors', 0);
            ExceptionHandler::register();
-        } elseif ($displayErrors && (!ini_get('log_errors') || ini_get('error_log'))) {
+        } elseif ($displayErrors && (!filter_var(ini_get('log_errors'), FILTER_VALIDATE_BOOLEAN) || ini_get('error_log'))) {
            // CLI - display errors only if they're not already logged to STDERR
            ini_set('display_errors', 1);
        }
--- a/DebugClassLoader.php
+++ b/DebugClassLoader.php
@@ -26,24 +26,25 @@ class DebugClassLoader
 {
    private $classLoader;
    private $isFinder;
+    private $loaded = [];
    private static $caseCheck;
-    private static $deprecated = array();
-    private static $php7Reserved = array('int', 'float', 'bool', 'string', 'true', 'false', 'null');
-    private static $darwinCache = array('/' => array('/', array()));
+    private static $checkedClasses = [];
+    private static $final = [];
+    private static $finalMethods = [];
+    private static $deprecated = [];
+    private static $internal = [];
+    private static $internalMethods = [];
+    private static $php7Reserved = ['int' => 1, 'float' => 1, 'bool' => 1, 'string' => 1, 'true' => 1, 'false' => 1, 'null' => 1];
+    private static $darwinCache = ['/' => ['/', []]];

-    /**
-     * Constructor.
-     *
-     * @param callable $classLoader A class loader
-     */
    public function __construct(callable $classLoader)
    {
        $this->classLoader = $classLoader;
-        $this->isFinder = is_array($classLoader) && method_exists($classLoader[0], 'findFile');
+        $this->isFinder = \is_array($classLoader) && method_exists($classLoader[0], 'findFile');

        if (!isset(self::$caseCheck)) {
-            $file = file_exists(__FILE__) ? __FILE__ : rtrim(realpath('.'), DIRECTORY_SEPARATOR);
-            $i = strrpos($file, DIRECTORY_SEPARATOR);
+            $file = file_exists(__FILE__) ? __FILE__ : rtrim(realpath('.'), \DIRECTORY_SEPARATOR);
+            $i = strrpos($file, \DIRECTORY_SEPARATOR);
            $dir = substr($file, 0, 1 + $i);
            $file = substr($file, 1 + $i);
            $test = strtoupper($file) === $file ? strtolower($file) : strtoupper($file);
@@ -52,7 +53,7 @@ class DebugClassLoader
            if (false === $test || false === $i) {
                // filesystem is case sensitive
                self::$caseCheck = 0;
-            } elseif (substr($test, -strlen($file)) === $file) {
+            } elseif (substr($test, -\strlen($file)) === $file) {
                // filesystem is case insensitive and realpath() normalizes the case of characters
                self::$caseCheck = 1;
            } elseif (false !== stripos(PHP_OS, 'darwin')) {
@@ -84,7 +85,7 @@ class DebugClassLoader
        class_exists('Symfony\Component\Debug\ErrorHandler');
        class_exists('Psr\Log\LogLevel');

-        if (!is_array($functions = spl_autoload_functions())) {
+        if (!\is_array($functions = spl_autoload_functions())) {
            return;
        }

@@ -93,8 +94,8 @@ class DebugClassLoader
        }

        foreach ($functions as $function) {
-            if (!is_array($function) || !$function[0] instanceof self) {
-                $function = array(new static($function), 'loadClass');
+            if (!\is_array($function) || !$function[0] instanceof self) {
+                $function = [new static($function), 'loadClass'];
            }

            spl_autoload_register($function);
@@ -106,7 +107,7 @@ class DebugClassLoader
     */
    public static function disable()
    {
-        if (!is_array($functions = spl_autoload_functions())) {
+        if (!\is_array($functions = spl_autoload_functions())) {
            return;
        }

@@ -115,7 +116,7 @@ class DebugClassLoader
        }

        foreach ($functions as $function) {
-            if (is_array($function) && $function[0] instanceof self) {
+            if (\is_array($function) && $function[0] instanceof self) {
                $function = $function[0]->getClassLoader();
            }

@@ -123,192 +124,324 @@ class DebugClassLoader
        }
    }

+    /**
+     * @return string|null
+     */
+    public function findFile($class)
+    {
+        return $this->isFinder ? $this->classLoader[0]->findFile($class) ?: null : null;
+    }
+
    /**
     * Loads the given class or interface.
     *
     * @param string $class The name of the class
     *
-     * @return bool|null True, if loaded
-     *
     * @throws \RuntimeException
     */
    public function loadClass($class)
    {
-        ErrorHandler::stackErrors();
+        $e = error_reporting(error_reporting() | E_PARSE | E_ERROR | E_CORE_ERROR | E_COMPILE_ERROR);

        try {
-            if ($this->isFinder) {
-                if ($file = $this->classLoader[0]->findFile($class)) {
-                    require_once $file;
+            if ($this->isFinder && !isset($this->loaded[$class])) {
+                $this->loaded[$class] = true;
+                if (!$file = $this->classLoader[0]->findFile($class) ?: false) {
+                    // no-op
+                } elseif (\function_exists('opcache_is_script_cached') && @opcache_is_script_cached($file)) {
+                    require $file;
+
+                    return;
+                } else {
+                    require $file;
                }
            } else {
-                call_user_func($this->classLoader, $class);
+                \call_user_func($this->classLoader, $class);
                $file = false;
            }
        } finally {
-            ErrorHandler::unstackErrors();
+            error_reporting($e);
        }

-        $exists = class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false);
+        $this->checkClass($class, $file);
+    }

-        if ('\\' === $class[0]) {
+    private function checkClass($class, $file = null)
+    {
+        $exists = null === $file || \class_exists($class, false) || \interface_exists($class, false) || \trait_exists($class, false);
+
+        if (null !== $file && $class && '\\' === $class[0]) {
            $class = substr($class, 1);
        }

        if ($exists) {
+            if (isset(self::$checkedClasses[$class])) {
+                return;
+            }
+            self::$checkedClasses[$class] = true;
+
            $refl = new \ReflectionClass($class);
+            if (null === $file && $refl->isInternal()) {
+                return;
+            }
            $name = $refl->getName();

-            if ($name !== $class && 0 === strcasecmp($name, $class)) {
-                throw new \RuntimeException(sprintf('Case mismatch between loaded and declared class names: %s vs %s', $class, $name));
+            if ($name !== $class && 0 === \strcasecmp($name, $class)) {
+                throw new \RuntimeException(sprintf('Case mismatch between loaded and declared class names: "%s" vs "%s".', $class, $name));
            }

-            if (in_array(strtolower($refl->getShortName()), self::$php7Reserved)) {
-                @trigger_error(sprintf('%s uses a reserved class name (%s) that will break on PHP 7 and higher', $name, $refl->getShortName()), E_USER_DEPRECATED);
-            } elseif (preg_match('#\n \* @deprecated (.*?)\r?\n \*(?: @|/$)#s', $refl->getDocComment(), $notice)) {
-                self::$deprecated[$name] = preg_replace('#\s*\r?\n \* +#', ' ', $notice[1]);
-            } else {
-                if (2 > $len = 1 + (strpos($name, '\\', 1 + strpos($name, '\\')) ?: strpos($name, '_'))) {
-                    $len = 0;
-                    $ns = '';
-                } else {
-                    switch ($ns = substr($name, 0, $len)) {
-                        case 'Symfony\Bridge\\':
-                        case 'Symfony\Bundle\\':
-                        case 'Symfony\Component\\':
-                            $ns = 'Symfony\\';
-                            $len = strlen($ns);
-                            break;
-                    }
-                }
-                $parent = get_parent_class($class);
+            $deprecations = $this->checkAnnotations($refl, $name);

-                if (!$parent || strncmp($ns, $parent, $len)) {
-                    if ($parent && isset(self::$deprecated[$parent]) && strncmp($ns, $parent, $len)) {
-                        @trigger_error(sprintf('The %s class extends %s that is deprecated %s', $name, $parent, self::$deprecated[$parent]), E_USER_DEPRECATED);
-                    }
+            if (isset(self::$php7Reserved[\strtolower($refl->getShortName())])) {
+                $deprecations[] = sprintf('The "%s" class uses the reserved name "%s", it will break on PHP 7 and higher', $name, $refl->getShortName());
+            }

-                    $parentInterfaces = array();
-                    $deprecatedInterfaces = array();
-                    if ($parent) {
-                        foreach (class_implements($parent) as $interface) {
-                            $parentInterfaces[$interface] = 1;
-                        }
-                    }
-
-                    foreach ($refl->getInterfaceNames() as $interface) {
-                        if (isset(self::$deprecated[$interface]) && strncmp($ns, $interface, $len)) {
-                            $deprecatedInterfaces[] = $interface;
-                        }
-                        foreach (class_implements($interface) as $interface) {
-                            $parentInterfaces[$interface] = 1;
-                        }
-                    }
-
-                    foreach ($deprecatedInterfaces as $interface) {
-                        if (!isset($parentInterfaces[$interface])) {
-                            @trigger_error(sprintf('The %s %s %s that is deprecated %s', $name, $refl->isInterface() ? 'interface extends' : 'class implements', $interface, self::$deprecated[$interface]), E_USER_DEPRECATED);
-                        }
-                    }
-                }
+            foreach ($deprecations as $message) {
+                @trigger_error($message, E_USER_DEPRECATED);
            }
        }

-        if ($file) {
-            if (!$exists) {
-                if (false !== strpos($class, '/')) {
-                    throw new \RuntimeException(sprintf('Trying to autoload a class with an invalid name "%s". Be careful that the namespace separator is "\" in PHP, not "/".', $class));
-                }
+        if (!$file) {
+            return;
+        }

-                throw new \RuntimeException(sprintf('The autoloader expected class "%s" to be defined in file "%s". The file was found but the class was not in it, the class name or namespace probably has a typo.', $class, $file));
-            }
-            if (self::$caseCheck) {
-                $real = explode('\\', $class.strrchr($file, '.'));
-                $tail = explode(DIRECTORY_SEPARATOR, str_replace('/', DIRECTORY_SEPARATOR, $file));
-
-                $i = count($tail) - 1;
-                $j = count($real) - 1;
-
-                while (isset($tail[$i], $real[$j]) && $tail[$i] === $real[$j]) {
-                    --$i;
-                    --$j;
-                }
-
-                array_splice($tail, 0, $i + 1);
-            }
-            if (self::$caseCheck && $tail) {
-                $tail = DIRECTORY_SEPARATOR.implode(DIRECTORY_SEPARATOR, $tail);
-                $tailLen = strlen($tail);
-                $real = $refl->getFileName();
-
-                if (2 === self::$caseCheck) {
-                    // realpath() on MacOSX doesn't normalize the case of characters
-
-                    $i = 1 + strrpos($real, '/');
-                    $file = substr($real, $i);
-                    $real = substr($real, 0, $i);
-
-                    if (isset(self::$darwinCache[$real])) {
-                        $kDir = $real;
-                    } else {
-                        $kDir = strtolower($real);
-
-                        if (isset(self::$darwinCache[$kDir])) {
-                            $real = self::$darwinCache[$kDir][0];
-                        } else {
-                            $dir = getcwd();
-                            chdir($real);
-                            $real = getcwd().'/';
-                            chdir($dir);
-
-                            $dir = $real;
-                            $k = $kDir;
-                            $i = strlen($dir) - 1;
-                            while (!isset(self::$darwinCache[$k])) {
-                                self::$darwinCache[$k] = array($dir, array());
-                                self::$darwinCache[$dir] = &self::$darwinCache[$k];
-
-                                while ('/' !== $dir[--$i]) {
-                                }
-                                $k = substr($k, 0, ++$i);
-                                $dir = substr($dir, 0, $i--);
-                            }
-                        }
-                    }
-
-                    $dirFiles = self::$darwinCache[$kDir][1];
-
-                    if (isset($dirFiles[$file])) {
-                        $kFile = $file;
-                    } else {
-                        $kFile = strtolower($file);
-
-                        if (!isset($dirFiles[$kFile])) {
-                            foreach (scandir($real, 2) as $f) {
-                                if ('.' !== $f[0]) {
-                                    $dirFiles[$f] = $f;
-                                    if ($f === $file) {
-                                        $kFile = $k = $file;
-                                    } elseif ($f !== $k = strtolower($f)) {
-                                        $dirFiles[$k] = $f;
-                                    }
-                                }
-                            }
-                            self::$darwinCache[$kDir][1] = $dirFiles;
-                        }
-                    }
-
-                    $real .= $dirFiles[$kFile];
-                }
-
-                if (0 === substr_compare($real, $tail, -$tailLen, $tailLen, true)
-                  && 0 !== substr_compare($real, $tail, -$tailLen, $tailLen, false)
-                ) {
-                    throw new \RuntimeException(sprintf('Case mismatch between class and real file names: %s vs %s in %s', substr($tail, -$tailLen + 1), substr($real, -$tailLen + 1), substr($real, 0, -$tailLen + 1)));
-                }
+        if (!$exists) {
+            if (false !== strpos($class, '/')) {
+                throw new \RuntimeException(sprintf('Trying to autoload a class with an invalid name "%s". Be careful that the namespace separator is "\" in PHP, not "/".', $class));
            }

-            return true;
+            throw new \RuntimeException(sprintf('The autoloader expected class "%s" to be defined in file "%s". The file was found but the class was not in it, the class name or namespace probably has a typo.', $class, $file));
+        }
+
+        if (self::$caseCheck && $message = $this->checkCase($refl, $file, $class)) {
+            throw new \RuntimeException(sprintf('Case mismatch between class and real file names: "%s" vs "%s" in "%s".', $message[0], $message[1], $message[2]));
        }
    }
+
+    public function checkAnnotations(\ReflectionClass $refl, $class)
+    {
+        $deprecations = [];
+
+        // Don't trigger deprecations for classes in the same vendor
+        if (2 > $len = 1 + (\strpos($class, '\\') ?: \strpos($class, '_'))) {
+            $len = 0;
+            $ns = '';
+        } else {
+            $ns = \str_replace('_', '\\', \substr($class, 0, $len));
+        }
+
+        // Detect annotations on the class
+        if (false !== $doc = $refl->getDocComment()) {
+            foreach (['final', 'deprecated', 'internal'] as $annotation) {
+                if (false !== \strpos($doc, $annotation) && preg_match('#\n\s+\* @'.$annotation.'(?:( .+?)\.?)?\r?\n\s+\*(?: @|/$)#s', $doc, $notice)) {
+                    self::${$annotation}[$class] = isset($notice[1]) ? preg_replace('#\.?\r?\n( \*)? *(?= |\r?\n|$)#', '', $notice[1]) : '';
+                }
+            }
+        }
+
+        $parent = \get_parent_class($class);
+        $parentAndOwnInterfaces = $this->getOwnInterfaces($class, $parent);
+        if ($parent) {
+            $parentAndOwnInterfaces[$parent] = $parent;
+
+            if (!isset(self::$checkedClasses[$parent])) {
+                $this->checkClass($parent);
+            }
+
+            if (isset(self::$final[$parent])) {
+                $deprecations[] = sprintf('The "%s" class is considered final%s. It may change without further notice as of its next major version. You should not extend it from "%s".', $parent, self::$final[$parent], $class);
+            }
+        }
+
+        // Detect if the parent is annotated
+        foreach ($parentAndOwnInterfaces + \class_uses($class, false) as $use) {
+            if (!isset(self::$checkedClasses[$use])) {
+                $this->checkClass($use);
+            }
+            if (isset(self::$deprecated[$use]) && \strncmp($ns, \str_replace('_', '\\', $use), $len)) {
+                $type = class_exists($class, false) ? 'class' : (interface_exists($class, false) ? 'interface' : 'trait');
+                $verb = class_exists($use, false) || interface_exists($class, false) ? 'extends' : (interface_exists($use, false) ? 'implements' : 'uses');
+
+                $deprecations[] = sprintf('The "%s" %s %s "%s" that is deprecated%s.', $class, $type, $verb, $use, self::$deprecated[$use]);
+            }
+            if (isset(self::$internal[$use]) && \strncmp($ns, \str_replace('_', '\\', $use), $len)) {
+                $deprecations[] = sprintf('The "%s" %s is considered internal%s. It may change without further notice. You should not use it from "%s".', $use, class_exists($use, false) ? 'class' : (interface_exists($use, false) ? 'interface' : 'trait'), self::$internal[$use], $class);
+            }
+        }
+
+        if (\trait_exists($class)) {
+            return $deprecations;
+        }
+
+        // Inherit @final and @internal annotations for methods
+        self::$finalMethods[$class] = [];
+        self::$internalMethods[$class] = [];
+        foreach ($parentAndOwnInterfaces as $use) {
+            foreach (['finalMethods', 'internalMethods'] as $property) {
+                if (isset(self::${$property}[$use])) {
+                    self::${$property}[$class] = self::${$property}[$class] ? self::${$property}[$use] + self::${$property}[$class] : self::${$property}[$use];
+                }
+            }
+        }
+
+        foreach ($refl->getMethods(\ReflectionMethod::IS_PUBLIC | \ReflectionMethod::IS_PROTECTED) as $method) {
+            if ($method->class !== $class) {
+                continue;
+            }
+
+            if ($parent && isset(self::$finalMethods[$parent][$method->name])) {
+                list($declaringClass, $message) = self::$finalMethods[$parent][$method->name];
+                $deprecations[] = sprintf('The "%s::%s()" method is considered final%s. It may change without further notice as of its next major version. You should not extend it from "%s".', $declaringClass, $method->name, $message, $class);
+            }
+
+            if (isset(self::$internalMethods[$class][$method->name])) {
+                list($declaringClass, $message) = self::$internalMethods[$class][$method->name];
+                if (\strncmp($ns, $declaringClass, $len)) {
+                    $deprecations[] = sprintf('The "%s::%s()" method is considered internal%s. It may change without further notice. You should not extend it from "%s".', $declaringClass, $method->name, $message, $class);
+                }
+            }
+
+            // Detect method annotations
+            if (false === $doc = $method->getDocComment()) {
+                continue;
+            }
+
+            foreach (['final', 'internal'] as $annotation) {
+                if (false !== \strpos($doc, $annotation) && preg_match('#\n\s+\* @'.$annotation.'(?:( .+?)\.?)?\r?\n\s+\*(?: @|/$)#s', $doc, $notice)) {
+                    $message = isset($notice[1]) ? preg_replace('#\.?\r?\n( \*)? *(?= |\r?\n|$)#', '', $notice[1]) : '';
+                    self::${$annotation.'Methods'}[$class][$method->name] = [$class, $message];
+                }
+            }
+        }
+
+        return $deprecations;
+    }
+
+    public function checkCase(\ReflectionClass $refl, $file, $class)
+    {
+        $real = explode('\\', $class.strrchr($file, '.'));
+        $tail = explode(\DIRECTORY_SEPARATOR, str_replace('/', \DIRECTORY_SEPARATOR, $file));
+
+        $i = \count($tail) - 1;
+        $j = \count($real) - 1;
+
+        while (isset($tail[$i], $real[$j]) && $tail[$i] === $real[$j]) {
+            --$i;
+            --$j;
+        }
+
+        array_splice($tail, 0, $i + 1);
+
+        if (!$tail) {
+            return;
+        }
+
+        $tail = \DIRECTORY_SEPARATOR.implode(\DIRECTORY_SEPARATOR, $tail);
+        $tailLen = \strlen($tail);
+        $real = $refl->getFileName();
+
+        if (2 === self::$caseCheck) {
+            $real = $this->darwinRealpath($real);
+        }
+
+        if (0 === substr_compare($real, $tail, -$tailLen, $tailLen, true)
+            && 0 !== substr_compare($real, $tail, -$tailLen, $tailLen, false)
+        ) {
+            return [substr($tail, -$tailLen + 1), substr($real, -$tailLen + 1), substr($real, 0, -$tailLen + 1)];
+        }
+    }
+
+    /**
+     * `realpath` on MacOSX doesn't normalize the case of characters.
+     */
+    private function darwinRealpath($real)
+    {
+        $i = 1 + strrpos($real, '/');
+        $file = substr($real, $i);
+        $real = substr($real, 0, $i);
+
+        if (isset(self::$darwinCache[$real])) {
+            $kDir = $real;
+        } else {
+            $kDir = strtolower($real);
+
+            if (isset(self::$darwinCache[$kDir])) {
+                $real = self::$darwinCache[$kDir][0];
+            } else {
+                $dir = getcwd();
+                chdir($real);
+                $real = getcwd().'/';
+                chdir($dir);
+
+                $dir = $real;
+                $k = $kDir;
+                $i = \strlen($dir) - 1;
+                while (!isset(self::$darwinCache[$k])) {
+                    self::$darwinCache[$k] = [$dir, []];
+                    self::$darwinCache[$dir] = &self::$darwinCache[$k];
+
+                    while ('/' !== $dir[--$i]) {
+                    }
+                    $k = substr($k, 0, ++$i);
+                    $dir = substr($dir, 0, $i--);
+                }
+            }
+        }
+
+        $dirFiles = self::$darwinCache[$kDir][1];
+
+        if (!isset($dirFiles[$file]) && ') : eval()\'d code' === substr($file, -17)) {
+            // Get the file name from "file_name.php(123) : eval()'d code"
+            $file = substr($file, 0, strrpos($file, '(', -17));
+        }
+
+        if (isset($dirFiles[$file])) {
+            return $real .= $dirFiles[$file];
+        }
+
+        $kFile = strtolower($file);
+
+        if (!isset($dirFiles[$kFile])) {
+            foreach (scandir($real, 2) as $f) {
+                if ('.' !== $f[0]) {
+                    $dirFiles[$f] = $f;
+                    if ($f === $file) {
+                        $kFile = $k = $file;
+                    } elseif ($f !== $k = strtolower($f)) {
+                        $dirFiles[$k] = $f;
+                    }
+                }
+            }
+            self::$darwinCache[$kDir][1] = $dirFiles;
+        }
+
+        return $real .= $dirFiles[$kFile];
+    }
+
+    /**
+     * `class_implements` includes interfaces from the parents so we have to manually exclude them.
+     *
+     * @param string       $class
+     * @param string|false $parent
+     *
+     * @return string[]
+     */
+    private function getOwnInterfaces($class, $parent)
+    {
+        $ownInterfaces = class_implements($class, false);
+
+        if ($parent) {
+            foreach (class_implements($parent, false) as $interface) {
+                unset($ownInterfaces[$interface]);
+            }
+        }
+
+        foreach ($ownInterfaces as $interface) {
+            foreach (class_implements($interface) as $interface) {
+                unset($ownInterfaces[$interface]);
+            }
+        }
+
+        return $ownInterfaces;
+    }
 }
--- a/ErrorHandler.php
+++ b/ErrorHandler.php
@@ -11,17 +11,17 @@

 namespace Symfony\Component\Debug;

-use Psr\Log\LogLevel;
 use Psr\Log\LoggerInterface;
+use Psr\Log\LogLevel;
 use Symfony\Component\Debug\Exception\ContextErrorException;
 use Symfony\Component\Debug\Exception\FatalErrorException;
 use Symfony\Component\Debug\Exception\FatalThrowableError;
 use Symfony\Component\Debug\Exception\OutOfMemoryException;
 use Symfony\Component\Debug\Exception\SilencedErrorContext;
-use Symfony\Component\Debug\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
-use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;
 use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
 use Symfony\Component\Debug\FatalErrorHandler\FatalErrorHandlerInterface;
+use Symfony\Component\Debug\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
+use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;

 /**
 * A generic ErrorHandler for the PHP engine.
@@ -48,7 +48,7 @@ use Symfony\Component\Debug\FatalErrorHandler\FatalErrorHandlerInterface;
 */
 class ErrorHandler
 {
-    private $levels = array(
+    private $levels = [
        E_DEPRECATED => 'Deprecated',
        E_USER_DEPRECATED => 'User Deprecated',
        E_NOTICE => 'Notice',
@@ -64,25 +64,25 @@ class ErrorHandler
        E_PARSE => 'Parse Error',
        E_ERROR => 'Error',
        E_CORE_ERROR => 'Core Error',
-    );
+    ];

-    private $loggers = array(
-        E_DEPRECATED => array(null, LogLevel::INFO),
-        E_USER_DEPRECATED => array(null, LogLevel::INFO),
-        E_NOTICE => array(null, LogLevel::WARNING),
-        E_USER_NOTICE => array(null, LogLevel::WARNING),
-        E_STRICT => array(null, LogLevel::WARNING),
-        E_WARNING => array(null, LogLevel::WARNING),
-        E_USER_WARNING => array(null, LogLevel::WARNING),
-        E_COMPILE_WARNING => array(null, LogLevel::WARNING),
-        E_CORE_WARNING => array(null, LogLevel::WARNING),
-        E_USER_ERROR => array(null, LogLevel::CRITICAL),
-        E_RECOVERABLE_ERROR => array(null, LogLevel::CRITICAL),
-        E_COMPILE_ERROR => array(null, LogLevel::CRITICAL),
-        E_PARSE => array(null, LogLevel::CRITICAL),
-        E_ERROR => array(null, LogLevel::CRITICAL),
-        E_CORE_ERROR => array(null, LogLevel::CRITICAL),
-    );
+    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
@@ -97,9 +97,12 @@ class ErrorHandler
    private $bootstrappingLogger;

    private static $reservedMemory;
-    private static $stackedErrors = array();
-    private static $stackedErrorLevels = array();
+    private static $stackedErrors = [];
+    private static $stackedErrorLevels = [];
    private static $toStringException = null;
+    private static $silencedErrorCache = [];
+    private static $silencedErrorCount = 0;
+    private static $exitCode = 0;

    /**
     * Registers the error handler.
@@ -120,21 +123,35 @@ class ErrorHandler
            $handler = new static();
        }

-        if (null === $prev = set_error_handler(array($handler, 'handleError'))) {
+        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(array($handler, 'handleError'), $handler->thrownErrors | $handler->loggedErrors);
+            set_error_handler([$handler, 'handleError'], $handler->thrownErrors | $handler->loggedErrors);
            $handler->isRoot = true;
        }

-        if ($handlerIsNew && is_array($prev) && $prev[0] instanceof self) {
+        if ($handlerIsNew && \is_array($prev) && $prev[0] instanceof self) {
            $handler = $prev[0];
            $replace = false;
        }
-        if ($replace || !$prev) {
-            $handler->setExceptionHandler(set_exception_handler(array($handler, 'handleException')));
-        } else {
+        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);
@@ -161,12 +178,12 @@ class ErrorHandler
     */
    public function setDefaultLogger(LoggerInterface $logger, $levels = E_ALL, $replace = false)
    {
-        $loggers = array();
+        $loggers = [];

-        if (is_array($levels)) {
+        if (\is_array($levels)) {
            foreach ($levels as $type => $logLevel) {
                if (empty($this->loggers[$type][0]) || $replace || $this->loggers[$type][0] === $this->bootstrappingLogger) {
-                    $loggers[$type] = array($logger, $logLevel);
+                    $loggers[$type] = [$logger, $logLevel];
                }
            }
        } else {
@@ -197,15 +214,15 @@ class ErrorHandler
    {
        $prevLogged = $this->loggedErrors;
        $prev = $this->loggers;
-        $flush = array();
+        $flush = [];

        foreach ($loggers as $type => $log) {
            if (!isset($prev[$type])) {
                throw new \InvalidArgumentException('Unknown error type: '.$type);
            }
-            if (!is_array($log)) {
-                $log = array($log);
-            } elseif (!array_key_exists(0, $log)) {
+            if (!\is_array($log)) {
+                $log = [$log];
+            } elseif (!\array_key_exists(0, $log)) {
                throw new \InvalidArgumentException('No logger provided');
            }
            if (null === $log[0]) {
@@ -336,14 +353,14 @@ class ErrorHandler
    {
        if ($prev !== $this->thrownErrors | $this->loggedErrors) {
            $handler = set_error_handler('var_dump');
-            $handler = is_array($handler) ? $handler[0] : null;
+            $handler = \is_array($handler) ? $handler[0] : null;
            restore_error_handler();
            if ($handler === $this) {
                restore_error_handler();
                if ($this->isRoot) {
-                    set_error_handler(array($this, 'handleError'), $this->thrownErrors | $this->loggedErrors);
+                    set_error_handler([$this, 'handleError'], $this->thrownErrors | $this->loggedErrors);
                } else {
-                    set_error_handler(array($this, 'handleError'));
+                    set_error_handler([$this, 'handleError']);
                }
            }
        }
@@ -366,22 +383,24 @@ class ErrorHandler
    public function handleError($type, $message, $file, $line)
    {
        // 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 = error_reporting() | E_RECOVERABLE_ERROR | E_USER_ERROR | E_DEPRECATED | E_USER_DEPRECATED;
+        $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 $type && $log;
+            return !$silenced && $type && $log;
        }
        $scope = $this->scopedErrors & $type;

-        if (4 < $numArgs = func_num_args()) {
-            $context = $scope ? (func_get_arg(4) ?: array()) : array();
+        if (4 < $numArgs = \func_num_args()) {
+            $context = $scope ? (func_get_arg(4) ?: []) : [];
            $backtrace = 5 < $numArgs ? func_get_arg(5) : null; // defined on HHVM
        } else {
-            $context = array();
+            $context = [];
            $backtrace = null;
        }

@@ -406,7 +425,28 @@ class ErrorHandler
            $errorAsException = self::$toStringException;
            self::$toStringException = null;
        } elseif (!$throw && !($type & $level)) {
-            $errorAsException = new SilencedErrorContext($type, $file, $line);
+            if (!isset(self::$silencedErrorCache[$id = $file.':'.$line])) {
+                $lightTrace = $this->tracedErrors & $type ? $this->cleanTrace(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 3), $type, $file, $line, false) : [];
+                $errorAsException = new SilencedErrorContext($type, $file, $line, $lightTrace);
+            } elseif (isset(self::$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 === $lightTrace) {
+                return;
+            }
        } else {
            if ($scope) {
                $errorAsException = new ContextErrorException($logMessage, 0, $type, $file, $line, $context);
@@ -417,22 +457,10 @@ class ErrorHandler
            // Clean the trace by removing function arguments and the first frames added by the error handler itself.
            if ($throw || $this->tracedErrors & $type) {
                $backtrace = $backtrace ?: $errorAsException->getTrace();
-                $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 + $i);
-                        break;
-                    }
-                }
-                if (!($throw || $this->scopedErrors & $type)) {
-                    for ($i = 0; isset($lightTrace[$i]); ++$i) {
-                        unset($lightTrace[$i]['args']);
-                    }
-                }
+                $lightTrace = $this->cleanTrace($backtrace, $type, $file, $line, $throw);
                $this->traceReflector->setValue($errorAsException, $lightTrace);
            } else {
-                $this->traceReflector->setValue($errorAsException, array());
+                $this->traceReflector->setValue($errorAsException, []);
            }
        }

@@ -482,23 +510,32 @@ class ErrorHandler
        if ($this->isRecursive) {
            $log = 0;
        } elseif (self::$stackedErrorLevels) {
-            self::$stackedErrors[] = array(
+            self::$stackedErrors[] = [
                $this->loggers[$type][0],
                ($type & $level) ? $this->loggers[$type][1] : LogLevel::DEBUG,
                $logMessage,
-                array('exception' => $errorAsException),
-            );
+                $errorAsException ? ['exception' => $errorAsException] : [],
+            ];
        } 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, array('exception' => $errorAsException));
+                $this->loggers[$type][0]->log($level, $logMessage, $errorAsException ? ['exception' => $errorAsException] : []);
            } finally {
                $this->isRecursive = false;
+
+                if (!\defined('HHVM_VERSION')) {
+                    set_error_handler($currentErrorHandler);
+                }
            }
        }

-        return $type && $log;
+        return !$silenced && $type && $log;
    }

    /**
@@ -511,35 +548,36 @@ class ErrorHandler
     */
    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) || $exception instanceof FatalThrowableError) {
            if ($exception instanceof FatalErrorException) {
                if ($exception instanceof FatalThrowableError) {
-                    $error = array(
+                    $error = [
                        'type' => $type,
                        'message' => $message = $exception->getMessage(),
                        'file' => $exception->getFile(),
                        'line' => $exception->getLine(),
-                    );
+                    ];
                } else {
                    $message = 'Fatal '.$exception->getMessage();
                }
            } elseif ($exception instanceof \ErrorException) {
                $message = 'Uncaught '.$exception->getMessage();
-                if ($exception instanceof ContextErrorException) {
-                    $e['context'] = $exception->getContext();
-                }
            } else {
                $message = 'Uncaught Exception: '.$exception->getMessage();
            }
        }
        if ($this->loggedErrors & $type) {
            try {
-                $this->loggers[$type][0]->log($this->loggers[$type][1], $message, array('exception' => $exception));
+                $this->loggers[$type][0]->log($this->loggers[$type][1], $message, ['exception' => $exception]);
            } catch (\Exception $handlerException) {
            } catch (\Throwable $handlerException) {
            }
@@ -552,18 +590,21 @@ class ErrorHandler
                }
            }
        }
-        if (empty($this->exceptionHandler)) {
-            throw $exception; // Give back $exception to the native handler
-        }
+        $exceptionHandler = $this->exceptionHandler;
+        $this->exceptionHandler = null;
        try {
-            call_user_func($this->exceptionHandler, $exception);
+            if (null !== $exceptionHandler) {
+                return \call_user_func($exceptionHandler, $exception);
+            }
+            $handlerException = $handlerException ?: $exception;
        } catch (\Exception $handlerException) {
        } catch (\Throwable $handlerException) {
        }
-        if (isset($handlerException)) {
-            $this->exceptionHandler = null;
-            $this->handleException($handlerException);
+        if ($exception === $handlerException) {
+            self::$reservedMemory = null; // Disable the fatal error handler
+            throw $exception; // Give back $exception to the native handler
        }
+        $this->handleException($handlerException);
    }

    /**
@@ -579,17 +620,41 @@ class ErrorHandler
            return;
        }

-        self::$reservedMemory = null;
+        $handler = self::$reservedMemory = null;
+        $handlers = [];
+        $previousHandler = null;
+        $sameHandlerLimit = 10;

-        $handler = set_error_handler('var_dump');
-        $handler = is_array($handler) ? $handler[0] : null;
-        restore_error_handler();
+        while (!\is_array($handler) || !$handler[0] instanceof self) {
+            $handler = set_exception_handler('var_dump');
+            restore_exception_handler();

-        if (!$handler instanceof self) {
+            if (!$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 (null === $error) {
+        if ($exit = null === $error) {
            $error = error_get_last();
        }

@@ -613,15 +678,21 @@ class ErrorHandler
            } else {
                $exception = new FatalErrorException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, true, $trace);
            }
-        } elseif (!isset($exception)) {
-            return;
        }

        try {
-            $handler->handleException($exception, $error);
+            if (isset($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); });
+        }
    }

    /**
@@ -634,17 +705,25 @@ class ErrorHandler
     *
     * The most important feature of this is to prevent
     * autoloading until unstackErrors() is called.
+     *
+     * @deprecated since version 3.4, to be removed in 4.0.
     */
    public static function stackErrors()
    {
+        @trigger_error('Support for stacking errors is deprecated since Symfony 3.4 and will be removed in 4.0.', E_USER_DEPRECATED);
+
        self::$stackedErrorLevels[] = error_reporting(error_reporting() | E_PARSE | E_ERROR | E_CORE_ERROR | E_COMPILE_ERROR);
    }

    /**
     * Unstacks stacked errors and forwards to the logger.
+     *
+     * @deprecated since version 3.4, to be removed in 4.0.
     */
    public static function unstackErrors()
    {
+        @trigger_error('Support for unstacking errors is deprecated since Symfony 3.4 and will be removed in 4.0.', E_USER_DEPRECATED);
+
        $level = array_pop(self::$stackedErrorLevels);

        if (null !== $level) {
@@ -657,7 +736,7 @@ class ErrorHandler

        if (empty(self::$stackedErrorLevels)) {
            $errors = self::$stackedErrors;
-            self::$stackedErrors = array();
+            self::$stackedErrors = [];

            foreach ($errors as $error) {
                $error[0]->log($error[1], $error[2], $error[3]);
@@ -674,10 +753,29 @@ class ErrorHandler
     */
    protected function getFatalErrorHandlers()
    {
-        return array(
+        return [
            new UndefinedFunctionFatalErrorHandler(),
            new UndefinedMethodFatalErrorHandler(),
            new ClassNotFoundFatalErrorHandler(),
-        );
+        ];
+    }
+
+    private function cleanTrace($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 + $i);
+                break;
+            }
+        }
+        if (!($throw || $this->scopedErrors & $type)) {
+            for ($i = 0; isset($lightTrace[$i]); ++$i) {
+                unset($lightTrace[$i]['args'], $lightTrace[$i]['object']);
+            }
+        }
+
+        return $lightTrace;
    }
 }
--- a/Exception/ClassNotFoundException.php
+++ b/Exception/ClassNotFoundException.php
@@ -26,6 +26,9 @@ class ClassNotFoundException extends FatalErrorException
            $previous->getSeverity(),
            $previous->getFile(),
            $previous->getLine(),
+            null,
+            true,
+            null,
            $previous->getPrevious()
        );
        $this->setTrace($previous->getTrace());
--- a/Exception/ContextErrorException.php
+++ b/Exception/ContextErrorException.php
@@ -15,12 +15,14 @@ namespace Symfony\Component\Debug\Exception;
 * Error Exception with Variable Context.
 *
 * @author Christian Sciberras <uuf6429@gmail.com>
+ *
+ * @deprecated since version 3.3. Instead, \ErrorException will be used directly in 4.0.
 */
 class ContextErrorException extends \ErrorException
 {
-    private $context = array();
+    private $context = [];

-    public function __construct($message, $code, $severity, $filename, $lineno, $context = array())
+    public function __construct($message, $code, $severity, $filename, $lineno, $context = [])
    {
        parent::__construct($message, $code, $severity, $filename, $lineno);
        $this->context = $context;
@@ -31,6 +33,8 @@ class ContextErrorException extends \ErrorException
     */
    public function getContext()
    {
+        @trigger_error(sprintf('The %s class is deprecated since Symfony 3.3 and will be removed in 4.0.', __CLASS__), E_USER_DEPRECATED);
+
        return $this->context;
    }
 }
--- a/Exception/FatalErrorException.php
+++ b/Exception/FatalErrorException.php
@@ -18,9 +18,9 @@ namespace Symfony\Component\Debug\Exception;
 */
 class FatalErrorException extends \ErrorException
 {
-    public function __construct($message, $code, $severity, $filename, $lineno, $traceOffset = null, $traceArgs = true, array $trace = null)
+    public function __construct($message, $code, $severity, $filename, $lineno, $traceOffset = null, $traceArgs = true, array $trace = null, $previous = null)
    {
-        parent::__construct($message, $code, $severity, $filename, $lineno);
+        parent::__construct($message, $code, $severity, $filename, $lineno, $previous);

        if (null !== $trace) {
            if (!$traceArgs) {
@@ -31,7 +31,7 @@ class FatalErrorException extends \ErrorException

            $this->setTrace($trace);
        } elseif (null !== $traceOffset) {
-            if (function_exists('xdebug_get_function_stack')) {
+            if (\function_exists('xdebug_get_function_stack')) {
                $trace = xdebug_get_function_stack();
                if (0 < $traceOffset) {
                    array_splice($trace, -$traceOffset);
@@ -60,13 +60,13 @@ class FatalErrorException extends \ErrorException

                unset($frame);
                $trace = array_reverse($trace);
-            } elseif (function_exists('symfony_debug_backtrace')) {
+            } elseif (\function_exists('symfony_debug_backtrace')) {
                $trace = symfony_debug_backtrace();
                if (0 < $traceOffset) {
                    array_splice($trace, 0, $traceOffset);
                }
            } else {
-                $trace = array();
+                $trace = [];
            }

            $this->setTrace($trace);
--- a/Exception/FatalThrowableError.php
+++ b/Exception/FatalThrowableError.php
@@ -36,7 +36,8 @@ class FatalThrowableError extends FatalErrorException
            $e->getCode(),
            $severity,
            $e->getFile(),
-            $e->getLine()
+            $e->getLine(),
+            $e->getPrevious()
        );

        $this->setTrace($e->getTrace());
--- a/Exception/FlattenException.php
+++ b/Exception/FlattenException.php
@@ -11,6 +11,7 @@

 namespace Symfony\Component\Debug\Exception;

+use Symfony\Component\HttpFoundation\Exception\RequestExceptionInterface;
 use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;

 /**
@@ -32,7 +33,7 @@ class FlattenException
    private $file;
    private $line;

-    public static function create(\Exception $exception, $statusCode = null, array $headers = array())
+    public static function create(\Exception $exception, $statusCode = null, array $headers = [])
    {
        $e = new static();
        $e->setMessage($exception->getMessage());
@@ -41,6 +42,8 @@ class FlattenException
        if ($exception instanceof HttpExceptionInterface) {
            $statusCode = $exception->getStatusCode();
            $headers = array_merge($headers, $exception->getHeaders());
+        } elseif ($exception instanceof RequestExceptionInterface) {
+            $statusCode = 400;
        }

        if (null === $statusCode) {
@@ -50,7 +53,7 @@ class FlattenException
        $e->setStatusCode($statusCode);
        $e->setHeaders($headers);
        $e->setTraceFromException($exception);
-        $e->setClass(get_class($exception));
+        $e->setClass(\get_class($exception));
        $e->setFile($exception->getFile());
        $e->setLine($exception->getLine());

@@ -67,13 +70,13 @@ class FlattenException

    public function toArray()
    {
-        $exceptions = array();
-        foreach (array_merge(array($this), $this->getAllPrevious()) as $exception) {
-            $exceptions[] = array(
+        $exceptions = [];
+        foreach (array_merge([$this], $this->getAllPrevious()) as $exception) {
+            $exceptions[] = [
                'message' => $exception->getMessage(),
                'class' => $exception->getClass(),
                'trace' => $exception->getTrace(),
-            );
+            ];
        }

        return $exceptions;
@@ -154,14 +157,14 @@ class FlattenException
        return $this->previous;
    }

-    public function setPrevious(FlattenException $previous)
+    public function setPrevious(self $previous)
    {
        $this->previous = $previous;
    }

    public function getAllPrevious()
    {
-        $exceptions = array();
+        $exceptions = [];
        $e = $this;
        while ($e = $e->getPrevious()) {
            $exceptions[] = $e;
@@ -182,8 +185,8 @@ class FlattenException

    public function setTrace($trace, $file, $line)
    {
-        $this->trace = array();
-        $this->trace[] = array(
+        $this->trace = [];
+        $this->trace[] = [
            'namespace' => '',
            'short_class' => '',
            'class' => '',
@@ -191,8 +194,8 @@ class FlattenException
            'function' => '',
            'file' => $file,
            'line' => $line,
-            'args' => array(),
-        );
+            'args' => [],
+        ];
        foreach ($trace as $entry) {
            $class = '';
            $namespace = '';
@@ -202,7 +205,7 @@ class FlattenException
                $namespace = implode('\\', $parts);
            }

-            $this->trace[] = array(
+            $this->trace[] = [
                'namespace' => $namespace,
                'short_class' => $class,
                'class' => isset($entry['class']) ? $entry['class'] : '',
@@ -210,41 +213,41 @@ class FlattenException
                'function' => isset($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']) : array(),
-            );
+                'args' => isset($entry['args']) ? $this->flattenArgs($entry['args']) : [],
+            ];
        }
    }

    private function flattenArgs($args, $level = 0, &$count = 0)
    {
-        $result = array();
+        $result = [];
        foreach ($args as $key => $value) {
            if (++$count > 1e4) {
-                return array('array', '*SKIPPED over 10000 entries*');
+                return ['array', '*SKIPPED over 10000 entries*'];
            }
            if ($value instanceof \__PHP_Incomplete_Class) {
                // is_object() returns false on PHP<=7.1
-                $result[$key] = array('incomplete-object', $this->getClassNameFromIncomplete($value));
-            } elseif (is_object($value)) {
-                $result[$key] = array('object', get_class($value));
-            } elseif (is_array($value)) {
+                $result[$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('array', '*DEEP NESTED ARRAY*');
+                    $result[$key] = ['array', '*DEEP NESTED ARRAY*'];
                } else {
-                    $result[$key] = array('array', $this->flattenArgs($value, $level + 1, $count));
+                    $result[$key] = ['array', $this->flattenArgs($value, $level + 1, $count)];
                }
            } elseif (null === $value) {
-                $result[$key] = array('null', null);
-            } elseif (is_bool($value)) {
-                $result[$key] = array('boolean', $value);
-            } elseif (is_int($value)) {
-                $result[$key] = array('integer', $value);
-            } elseif (is_float($value)) {
-                $result[$key] = array('float', $value);
-            } elseif (is_resource($value)) {
-                $result[$key] = array('resource', get_resource_type($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] = array('string', (string) $value);
+                $result[$key] = ['string', (string) $value];
            }
        }

--- a/Exception/SilencedErrorContext.php
+++ b/Exception/SilencedErrorContext.php
@@ -18,15 +18,20 @@ namespace Symfony\Component\Debug\Exception;
 */
 class SilencedErrorContext implements \JsonSerializable
 {
+    public $count = 1;
+
    private $severity;
    private $file;
    private $line;
+    private $trace;

-    public function __construct($severity, $file, $line)
+    public function __construct($severity, $file, $line, array $trace = [], $count = 1)
    {
        $this->severity = $severity;
        $this->file = $file;
        $this->line = $line;
+        $this->trace = $trace;
+        $this->count = $count;
    }

    public function getSeverity()
@@ -44,12 +49,19 @@ class SilencedErrorContext implements \JsonSerializable
        return $this->line;
    }

+    public function getTrace()
+    {
+        return $this->trace;
+    }
+
    public function JsonSerialize()
    {
-        return array(
+        return [
            'severity' => $this->severity,
            'file' => $this->file,
            'line' => $this->line,
-        );
+            'trace' => $this->trace,
+            'count' => $this->count,
+        ];
    }
 }
--- a/Exception/UndefinedFunctionException.php
+++ b/Exception/UndefinedFunctionException.php
@@ -26,6 +26,9 @@ class UndefinedFunctionException extends FatalErrorException
            $previous->getSeverity(),
            $previous->getFile(),
            $previous->getLine(),
+            null,
+            true,
+            null,
            $previous->getPrevious()
        );
        $this->setTrace($previous->getTrace());
--- a/Exception/UndefinedMethodException.php
+++ b/Exception/UndefinedMethodException.php
@@ -26,6 +26,9 @@ class UndefinedMethodException extends FatalErrorException
            $previous->getSeverity(),
            $previous->getFile(),
            $previous->getLine(),
+            null,
+            true,
+            null,
            $previous->getPrevious()
        );
        $this->setTrace($previous->getTrace());
--- a/ExceptionHandler.php
+++ b/ExceptionHandler.php
--- a/FatalErrorHandler/ClassNotFoundFatalErrorHandler.php
+++ b/FatalErrorHandler/ClassNotFoundFatalErrorHandler.php
@@ -11,11 +11,11 @@

 namespace Symfony\Component\Debug\FatalErrorHandler;

-use Symfony\Component\Debug\Exception\ClassNotFoundException;
-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\Debug\DebugClassLoader;
 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;

 /**
 * ErrorHandler for classes that do not exist.
@@ -29,9 +29,9 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
     */
    public function handleError(array $error, FatalErrorException $exception)
    {
-        $messageLen = strlen($error['message']);
+        $messageLen = \strlen($error['message']);
        $notFoundSuffix = '\' not found';
-        $notFoundSuffixLen = strlen($notFoundSuffix);
+        $notFoundSuffixLen = \strlen($notFoundSuffix);
        if ($notFoundSuffixLen > $messageLen) {
            return;
        }
@@ -40,9 +40,9 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
            return;
        }

-        foreach (array('class', 'interface', 'trait') as $typeName) {
+        foreach (['class', 'interface', 'trait'] as $typeName) {
            $prefix = ucfirst($typeName).' \'';
-            $prefixLen = strlen($prefix);
+            $prefixLen = \strlen($prefix);
            if (0 !== strpos($error['message'], $prefix)) {
                continue;
            }
@@ -85,22 +85,22 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
     */
    private function getClassCandidates($class)
    {
-        if (!is_array($functions = spl_autoload_functions())) {
-            return array();
+        if (!\is_array($functions = spl_autoload_functions())) {
+            return [];
        }

        // find Symfony and Composer autoloaders
-        $classes = array();
+        $classes = [];

        foreach ($functions as $function) {
-            if (!is_array($function)) {
+            if (!\is_array($function)) {
                continue;
            }
            // get class loaders wrapped by DebugClassLoader
            if ($function[0] instanceof DebugClassLoader) {
                $function = $function[0]->getClassLoader();

-                if (!is_array($function)) {
+                if (!\is_array($function)) {
                    continue;
                }
            }
@@ -133,11 +133,11 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
     */
    private function findClassInPath($path, $class, $prefix)
    {
-        if (!$path = realpath($path.'/'.strtr($prefix, '\\_', '//')) ?: realpath($path.'/'.dirname(strtr($prefix, '\\_', '//'))) ?: realpath($path)) {
-            return array();
+        if (!$path = realpath($path.'/'.strtr($prefix, '\\_', '//')) ?: realpath($path.'/'.\dirname(strtr($prefix, '\\_', '//'))) ?: realpath($path)) {
+            return [];
        }

-        $classes = array();
+        $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(), $prefix)) {
@@ -157,9 +157,9 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
     */
    private function convertFileToClass($path, $file, $prefix)
    {
-        $candidates = array(
+        $candidates = [
            // namespaced class
-            $namespacedClass = str_replace(array($path.DIRECTORY_SEPARATOR, '.php', '/'), array('', '', '\\'), $file),
+            $namespacedClass = str_replace([$path.\DIRECTORY_SEPARATOR, '.php', '/'], ['', '', '\\'], $file),
            // namespaced class (with target dir)
            $prefix.$namespacedClass,
            // namespaced class (with target dir and separator)
@@ -170,7 +170,7 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
            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); });
--- a/FatalErrorHandler/UndefinedFunctionFatalErrorHandler.php
+++ b/FatalErrorHandler/UndefinedFunctionFatalErrorHandler.php
@@ -11,8 +11,8 @@

 namespace Symfony\Component\Debug\FatalErrorHandler;

-use Symfony\Component\Debug\Exception\UndefinedFunctionException;
 use Symfony\Component\Debug\Exception\FatalErrorException;
+use Symfony\Component\Debug\Exception\UndefinedFunctionException;

 /**
 * ErrorHandler for undefined functions.
@@ -26,9 +26,9 @@ class UndefinedFunctionFatalErrorHandler implements FatalErrorHandlerInterface
     */
    public function handleError(array $error, FatalErrorException $exception)
    {
-        $messageLen = strlen($error['message']);
+        $messageLen = \strlen($error['message']);
        $notFoundSuffix = '()';
-        $notFoundSuffixLen = strlen($notFoundSuffix);
+        $notFoundSuffixLen = \strlen($notFoundSuffix);
        if ($notFoundSuffixLen > $messageLen) {
            return;
        }
@@ -38,7 +38,7 @@ class UndefinedFunctionFatalErrorHandler implements FatalErrorHandlerInterface
        }

        $prefix = 'Call to undefined function ';
-        $prefixLen = strlen($prefix);
+        $prefixLen = \strlen($prefix);
        if (0 !== strpos($error['message'], $prefix)) {
            return;
        }
@@ -53,7 +53,7 @@ class UndefinedFunctionFatalErrorHandler implements FatalErrorHandlerInterface
            $message = sprintf('Attempted to call function "%s" from the global namespace.', $functionName);
        }

-        $candidates = array();
+        $candidates = [];
        foreach (get_defined_functions() as $type => $definedFunctionNames) {
            foreach ($definedFunctionNames as $definedFunctionName) {
                if (false !== $namespaceSeparatorIndex = strrpos($definedFunctionName, '\\')) {
--- a/FatalErrorHandler/UndefinedMethodFatalErrorHandler.php
+++ b/FatalErrorHandler/UndefinedMethodFatalErrorHandler.php
@@ -41,10 +41,10 @@ class UndefinedMethodFatalErrorHandler implements FatalErrorHandlerInterface
            return new UndefinedMethodException($message, $exception);
        }

-        $candidates = array();
+        $candidates = [];
        foreach ($methods as $definedMethodName) {
            $lev = levenshtein($methodName, $definedMethodName);
-            if ($lev <= strlen($methodName) / 3 || false !== strpos($definedMethodName, $methodName)) {
+            if ($lev <= \strlen($methodName) / 3 || false !== strpos($definedMethodName, $methodName)) {
                $candidates[] = $definedMethodName;
            }
        }
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-Copyright (c) 2004-2017 Fabien Potencier
+Copyright (c) 2004-2019 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
--- a/Resources/ext/README.md
+++ b/Resources/ext/README.md
@@ -25,41 +25,41 @@ function symfony_zval_info($key, $array, $options = 0)
        return null;
    }

-    $info = array(
+    $info = [
        'type' => gettype($array[$key]),
        'zval_hash' => /* hashed memory address of $array[$key] */,
        'zval_refcount' => /* internal zval refcount of $array[$key] */,
        'zval_isref' => /* is_ref status of $array[$key] */,
-    );
+    ];

    switch ($info['type']) {
        case 'object':
-            $info += array(
+            $info += [
                'object_class' => get_class($array[$key]),
                'object_refcount' => /* internal object refcount of $array[$key] */,
                'object_hash' => spl_object_hash($array[$key]),
                'object_handle' => /* internal object handle $array[$key] */,
-            );
+            ];
            break;

        case 'resource':
-            $info += array(
+            $info += [
                'resource_handle' => (int) $array[$key],
                'resource_type' => get_resource_type($array[$key]),
                'resource_refcount' => /* internal resource refcount of $array[$key] */,
-            );
+            ];
            break;

        case 'array':
-            $info += array(
+            $info += [
                'array_count' => count($array[$key]),
-            );
+            ];
            break;

        case 'string':
-            $info += array(
+            $info += [
                'strlen' => strlen($array[$key]),
-            );
+            ];
            break;
    }

--- a/Resources/ext/tests/001.phpt
+++ b/Resources/ext/tests/001.phpt
@@ -1,7 +1,9 @@
 --TEST--
 Test symfony_zval_info API
 --SKIPIF--
-<?php if (!extension_loaded('symfony_debug')) print 'skip'; ?>
+<?php if (!extension_loaded('symfony_debug')) {
+    echo 'skip';
+} ?>
 --FILE--
 <?php

@@ -9,7 +11,7 @@ $int = 42;
 $float = 42.42;
 $str = 'foobar';
 $object = new StdClass();
-$array = array('foo', 'bar');
+$array = ['foo', 'bar'];
 $resource = tmpfile();
 $null = null;
 $bool = true;
@@ -17,7 +19,7 @@ $bool = true;
 $anotherint = 42;
 $refcount2 = &$anotherint;

-$var = array(
+$var = [
    'int' => $int,
    'float' => $float,
    'str' => $str,
@@ -27,7 +29,7 @@ $var = array(
    'null' => $null,
    'bool' => $bool,
    'refcount' => &$refcount2,
-);
+];

 var_dump(symfony_zval_info('int', $var));
 var_dump(symfony_zval_info('float', $var));
--- a/Resources/ext/tests/002.phpt
+++ b/Resources/ext/tests/002.phpt
@@ -1,7 +1,9 @@
 --TEST--
 Test symfony_debug_backtrace in case of fatal error
 --SKIPIF--
-<?php if (!extension_loaded('symfony_debug')) print 'skip'; ?>
+<?php if (!extension_loaded('symfony_debug')) {
+    echo 'skip';
+} ?>
 --FILE--
 <?php

--- a/Resources/ext/tests/002_1.phpt
+++ b/Resources/ext/tests/002_1.phpt
@@ -1,7 +1,9 @@
 --TEST--
 Test symfony_debug_backtrace in case of non fatal error
 --SKIPIF--
-<?php if (!extension_loaded('symfony_debug')) print 'skip'; ?>
+<?php if (!extension_loaded('symfony_debug')) {
+    echo 'skip';
+} ?>
 --FILE--
 <?php

--- a/Resources/ext/tests/003.phpt
+++ b/Resources/ext/tests/003.phpt
@@ -1,7 +1,9 @@
 --TEST--
 Test ErrorHandler in case of fatal error
 --SKIPIF--
-<?php if (!extension_loaded('symfony_debug')) print 'skip'; ?>
+<?php if (!extension_loaded('symfony_debug')) {
+    echo 'skip';
+} ?>
 --FILE--
 <?php

@@ -43,7 +45,7 @@ function foo()
 $handler = ErrorHandler::register();
 $handler->setExceptionHandler('print_r');

-if (function_exists('xdebug_disable')) {
+if (\function_exists('xdebug_disable')) {
    xdebug_disable();
 }

--- a/Tests/DebugClassLoaderTest.php
+++ b/Tests/DebugClassLoaderTest.php
@@ -11,10 +11,11 @@

 namespace Symfony\Component\Debug\Tests;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Debug\DebugClassLoader;
 use Symfony\Component\Debug\ErrorHandler;

-class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
+class DebugClassLoaderTest extends TestCase
 {
    /**
     * @var int Error reporting level before running tests
@@ -27,14 +28,14 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
    {
        $this->errorReporting = error_reporting(E_ALL);
        $this->loader = new ClassLoader();
-        spl_autoload_register(array($this->loader, 'loadClass'), true, true);
+        spl_autoload_register([$this->loader, 'loadClass'], true, true);
        DebugClassLoader::enable();
    }

    protected function tearDown()
    {
        DebugClassLoader::disable();
-        spl_autoload_unregister(array($this->loader, 'loadClass'));
+        spl_autoload_unregister([$this->loader, 'loadClass']);
        error_reporting($this->errorReporting);
    }

@@ -44,7 +45,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase

        $functions = spl_autoload_functions();
        foreach ($functions as $function) {
-            if (is_array($function) && $function[0] instanceof DebugClassLoader) {
+            if (\is_array($function) && $function[0] instanceof DebugClassLoader) {
                $reflClass = new \ReflectionClass($function[0]);
                $reflProp = $reflClass->getProperty('classLoader');
                $reflProp->setAccessible(true);
@@ -58,12 +59,29 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        $this->fail('DebugClassLoader did not register');
    }

+    /**
+     * @expectedException \Exception
+     * @expectedExceptionMessage boo
+     */
+    public function testThrowingClass()
+    {
+        try {
+            class_exists(__NAMESPACE__.'\Fixtures\Throwing');
+            $this->fail('Exception expected');
+        } catch (\Exception $e) {
+            $this->assertSame('boo', $e->getMessage());
+        }
+
+        // the second call also should throw
+        class_exists(__NAMESPACE__.'\Fixtures\Throwing');
+    }
+
    public function testUnsilencing()
    {
-        if (PHP_VERSION_ID >= 70000) {
+        if (\PHP_VERSION_ID >= 70000) {
            $this->markTestSkipped('PHP7 throws exceptions, unsilencing is not required anymore.');
        }
-        if (defined('HHVM_VERSION')) {
+        if (\defined('HHVM_VERSION')) {
            $this->markTestSkipped('HHVM is not handled in this test case.');
        }

@@ -88,7 +106,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        if (class_exists('Symfony\Component\Debug\Exception\ContextErrorException', false)) {
            $this->markTestSkipped('The ContextErrorException class is already loaded.');
        }
-        if (defined('HHVM_VERSION')) {
+        if (\defined('HHVM_VERSION')) {
            $this->markTestSkipped('HHVM is not handled in this test case.');
        }

@@ -108,7 +126,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        } catch (\ErrorException $exception) {
            // if an exception is thrown, the test passed
            $this->assertStringStartsWith(__FILE__, $exception->getFile());
-            if (PHP_VERSION_ID < 70000) {
+            if (\PHP_VERSION_ID < 70000) {
                $this->assertRegExp('/^Runtime Notice: Declaration/', $exception->getMessage());
                $this->assertEquals(E_STRICT, $exception->getSeverity());
            } else {
@@ -123,6 +141,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase

    /**
     * @expectedException \RuntimeException
+     * @expectedExceptionMessage Case mismatch between loaded and declared class names
     */
    public function testNameCaseMismatch()
    {
@@ -144,6 +163,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase

    /**
     * @expectedException \RuntimeException
+     * @expectedExceptionMessage Case mismatch between loaded and declared class names
     */
    public function testPsr4CaseMismatch()
    {
@@ -172,7 +192,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
    {
        set_error_handler(function () { return false; });
        $e = error_reporting(0);
-        trigger_error('', E_USER_DEPRECATED);
+        @trigger_error('', E_USER_DEPRECATED);

        class_exists('Test\\'.__NAMESPACE__.'\\'.$class, true);

@@ -182,20 +202,20 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        $lastError = error_get_last();
        unset($lastError['file'], $lastError['line']);

-        $xError = array(
+        $xError = [
            'type' => E_USER_DEPRECATED,
-            'message' => 'The Test\Symfony\Component\Debug\Tests\\'.$class.' class '.$type.' Symfony\Component\Debug\Tests\Fixtures\\'.$super.' that is deprecated but this is a test deprecation notice.',
-        );
+            'message' => 'The "Test\Symfony\Component\Debug\Tests\\'.$class.'" class '.$type.' "Symfony\Component\Debug\Tests\Fixtures\\'.$super.'" that is deprecated but this is a test deprecation notice.',
+        ];

        $this->assertSame($xError, $lastError);
    }

    public function provideDeprecatedSuper()
    {
-        return array(
-            array('DeprecatedInterfaceClass', 'DeprecatedInterface', 'implements'),
-            array('DeprecatedParentClass', 'DeprecatedClass', 'extends'),
-        );
+        return [
+            ['DeprecatedInterfaceClass', 'DeprecatedInterface', 'implements'],
+            ['DeprecatedParentClass', 'DeprecatedClass', 'extends'],
+        ];
    }

    public function testInterfaceExtendsDeprecatedInterface()
@@ -212,10 +232,10 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        $lastError = error_get_last();
        unset($lastError['file'], $lastError['line']);

-        $xError = array(
+        $xError = [
            'type' => E_USER_NOTICE,
            'message' => '',
-        );
+        ];

        $this->assertSame($xError, $lastError);
    }
@@ -234,17 +254,17 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        $lastError = error_get_last();
        unset($lastError['file'], $lastError['line']);

-        $xError = array(
+        $xError = [
            'type' => E_USER_NOTICE,
            'message' => '',
-        );
+        ];

        $this->assertSame($xError, $lastError);
    }

    public function testReservedForPhp7()
    {
-        if (PHP_VERSION_ID >= 70000) {
+        if (\PHP_VERSION_ID >= 70000) {
            $this->markTestSkipped('PHP7 already prevents using reserved names.');
        }

@@ -260,13 +280,116 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
        $lastError = error_get_last();
        unset($lastError['file'], $lastError['line']);

-        $xError = array(
+        $xError = [
            'type' => E_USER_DEPRECATED,
-            'message' => 'Test\Symfony\Component\Debug\Tests\Float uses a reserved class name (Float) that will break on PHP 7 and higher',
-        );
+            'message' => 'The "Test\Symfony\Component\Debug\Tests\Float" class uses the reserved name "Float", it will break on PHP 7 and higher',
+        ];

        $this->assertSame($xError, $lastError);
    }
+
+    public function testExtendedFinalClass()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        require __DIR__.'/Fixtures/FinalClasses.php';
+
+        $i = 1;
+        while (class_exists($finalClass = __NAMESPACE__.'\\Fixtures\\FinalClass'.$i++, false)) {
+            spl_autoload_call($finalClass);
+            class_exists('Test\\'.__NAMESPACE__.'\\Extends'.substr($finalClass, strrpos($finalClass, '\\') + 1), true);
+        }
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $this->assertSame([
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass1" class is considered final since version 3.3. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass1".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass2" class is considered final. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass2".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass3" class is considered final comment with @@@ and ***. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass3".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass4" class is considered final. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass4".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass5" class is considered final multiline comment. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass5".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass6" class is considered final. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass6".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass7" class is considered final another multiline comment... It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass7".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalClass8" class is considered final. It may change without further notice as of its next major version. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsFinalClass8".',
+        ], $deprecations);
+    }
+
+    public function testExtendedFinalMethod()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        class_exists(__NAMESPACE__.'\\Fixtures\\ExtendedFinalMethod', true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $xError = [
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalMethod::finalMethod()" method is considered final since version 3.3. It may change without further notice as of its next major version. You should not extend it from "Symfony\Component\Debug\Tests\Fixtures\ExtendedFinalMethod".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\FinalMethod::finalMethod2()" method is considered final. It may change without further notice as of its next major version. You should not extend it from "Symfony\Component\Debug\Tests\Fixtures\ExtendedFinalMethod".',
+        ];
+
+        $this->assertSame($xError, $deprecations);
+    }
+
+    public function testExtendedDeprecatedMethodDoesntTriggerAnyNotice()
+    {
+        set_error_handler(function () { return false; });
+        $e = error_reporting(0);
+        trigger_error('', E_USER_NOTICE);
+
+        class_exists('Test\\'.__NAMESPACE__.'\\ExtendsAnnotatedClass', true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $lastError = error_get_last();
+        unset($lastError['file'], $lastError['line']);
+
+        $this->assertSame(['type' => E_USER_NOTICE, 'message' => ''], $lastError);
+    }
+
+    public function testInternalsUse()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        class_exists('Test\\'.__NAMESPACE__.'\\ExtendsInternals', true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $this->assertSame($deprecations, [
+            'The "Symfony\Component\Debug\Tests\Fixtures\InternalInterface" interface is considered internal. It may change without further notice. You should not use it from "Test\Symfony\Component\Debug\Tests\ExtendsInternalsParent".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\InternalClass" class is considered internal since version 3.4. It may change without further notice. You should not use it from "Test\Symfony\Component\Debug\Tests\ExtendsInternalsParent".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\InternalTrait" trait is considered internal. It may change without further notice. You should not use it from "Test\Symfony\Component\Debug\Tests\ExtendsInternals".',
+            'The "Symfony\Component\Debug\Tests\Fixtures\InternalClass::internalMethod()" method is considered internal since version 3.4. It may change without further notice. You should not extend it from "Test\Symfony\Component\Debug\Tests\ExtendsInternals".',
+        ]);
+    }
+
+    public function testUseTraitWithInternalMethod()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        class_exists('Test\\'.__NAMESPACE__.'\\UseTraitWithInternalMethod', true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $this->assertSame([], $deprecations);
+    }
+
+    public function testEvaluatedCode()
+    {
+        $this->assertTrue(class_exists(__NAMESPACE__.'\Fixtures\DefinitionInEvaluatedCode', true));
+    }
 }

 class ClassLoader
@@ -277,12 +400,12 @@ class ClassLoader

    public function getClassMap()
    {
-        return array(__NAMESPACE__.'\Fixtures\NotPSR0bis' => __DIR__.'/Fixtures/notPsr0Bis.php');
+        return [__NAMESPACE__.'\Fixtures\NotPSR0bis' => __DIR__.'/Fixtures/notPsr0Bis.php'];
    }

    public function findFile($class)
    {
-        $fixtureDir = __DIR__.DIRECTORY_SEPARATOR.'Fixtures'.DIRECTORY_SEPARATOR;
+        $fixtureDir = __DIR__.\DIRECTORY_SEPARATOR.'Fixtures'.\DIRECTORY_SEPARATOR;

        if (__NAMESPACE__.'\TestingUnsilencing' === $class) {
            eval('-- parse error --');
@@ -290,16 +413,12 @@ class ClassLoader
            eval('namespace '.__NAMESPACE__.'; class TestingStacking { function foo() {} }');
        } elseif (__NAMESPACE__.'\TestingCaseMismatch' === $class) {
            eval('namespace '.__NAMESPACE__.'; class TestingCaseMisMatch {}');
-        } elseif (__NAMESPACE__.'\Fixtures\CaseMismatch' === $class) {
-            return $fixtureDir.'CaseMismatch.php';
        } elseif (__NAMESPACE__.'\Fixtures\Psr4CaseMismatch' === $class) {
-            return $fixtureDir.'psr4'.DIRECTORY_SEPARATOR.'Psr4CaseMismatch.php';
+            return $fixtureDir.'psr4'.\DIRECTORY_SEPARATOR.'Psr4CaseMismatch.php';
        } elseif (__NAMESPACE__.'\Fixtures\NotPSR0' === $class) {
            return $fixtureDir.'reallyNotPsr0.php';
        } elseif (__NAMESPACE__.'\Fixtures\NotPSR0bis' === $class) {
            return $fixtureDir.'notPsr0Bis.php';
-        } elseif (__NAMESPACE__.'\Fixtures\DeprecatedInterface' === $class) {
-            return $fixtureDir.'DeprecatedInterface.php';
        } elseif ('Symfony\Bridge\Debug\Tests\Fixtures\ExtendsDeprecatedParent' === $class) {
            eval('namespace Symfony\Bridge\Debug\Tests\Fixtures; class ExtendsDeprecatedParent extends \\'.__NAMESPACE__.'\Fixtures\DeprecatedClass {}');
        } elseif ('Test\\'.__NAMESPACE__.'\DeprecatedParentClass' === $class) {
@@ -310,6 +429,23 @@ class ClassLoader
            eval('namespace Test\\'.__NAMESPACE__.'; class NonDeprecatedInterfaceClass implements \\'.__NAMESPACE__.'\Fixtures\NonDeprecatedInterface {}');
        } elseif ('Test\\'.__NAMESPACE__.'\Float' === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class Float {}');
+        } elseif (0 === strpos($class, 'Test\\'.__NAMESPACE__.'\ExtendsFinalClass')) {
+            $classShortName = substr($class, strrpos($class, '\\') + 1);
+            eval('namespace Test\\'.__NAMESPACE__.'; class '.$classShortName.' extends \\'.__NAMESPACE__.'\Fixtures\\'.substr($classShortName, 7).' {}');
+        } elseif ('Test\\'.__NAMESPACE__.'\ExtendsAnnotatedClass' === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsAnnotatedClass extends \\'.__NAMESPACE__.'\Fixtures\AnnotatedClass {
+                public function deprecatedMethod() { }
+            }');
+        } elseif ('Test\\'.__NAMESPACE__.'\ExtendsInternals' === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsInternals extends ExtendsInternalsParent {
+                use \\'.__NAMESPACE__.'\Fixtures\InternalTrait;
+
+                public function internalMethod() { }
+            }');
+        } elseif ('Test\\'.__NAMESPACE__.'\ExtendsInternalsParent' === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsInternalsParent extends \\'.__NAMESPACE__.'\Fixtures\InternalClass implements \\'.__NAMESPACE__.'\Fixtures\InternalInterface { }');
+        } elseif ('Test\\'.__NAMESPACE__.'\UseTraitWithInternalMethod' === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class UseTraitWithInternalMethod { use \\'.__NAMESPACE__.'\Fixtures\TraitWithInternalMethod; }');
        }
    }
 }
--- a/Tests/ErrorHandlerTest.php
+++ b/Tests/ErrorHandlerTest.php
@@ -11,11 +11,14 @@

 namespace Symfony\Component\Debug\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\ContextErrorException;
 use Symfony\Component\Debug\Exception\SilencedErrorContext;
+use Symfony\Component\Debug\Tests\Fixtures\ErrorHandlerThatUsesThePreviousOne;
+use Symfony\Component\Debug\Tests\Fixtures\LoggerThatSetAnErrorHandler;

 /**
 * ErrorHandlerTest.
@@ -23,7 +26,7 @@ use Symfony\Component\Debug\Exception\SilencedErrorContext;
 * @author Robert Schönthal <seroscho@googlemail.com>
 * @author Nicolas Grekas <p@tchwork.com>
 */
-class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
+class ErrorHandlerTest extends TestCase
 {
    public function testRegister()
    {
@@ -35,16 +38,16 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase

            $newHandler = new ErrorHandler();

-            $this->assertSame($newHandler, ErrorHandler::register($newHandler, false));
+            $this->assertSame($handler, ErrorHandler::register($newHandler, false));
            $h = set_error_handler('var_dump');
            restore_error_handler();
-            $this->assertSame(array($handler, 'handleError'), $h);
+            $this->assertSame([$handler, 'handleError'], $h);

            try {
                $this->assertSame($newHandler, ErrorHandler::register($newHandler, true));
                $h = set_error_handler('var_dump');
                restore_error_handler();
-                $this->assertSame(array($newHandler, 'handleError'), $h);
+                $this->assertSame([$newHandler, 'handleError'], $h);
            } catch (\Exception $e) {
            }

@@ -65,19 +68,42 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        }
    }

+    public function testErrorGetLast()
+    {
+        $handler = ErrorHandler::register();
+        $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
+        $handler->setDefaultLogger($logger);
+        $handler->screamAt(E_ALL);
+
+        try {
+            @trigger_error('Hello', E_USER_WARNING);
+            $expected = [
+                'type' => E_USER_WARNING,
+                'message' => 'Hello',
+                'file' => __FILE__,
+                'line' => __LINE__ - 5,
+            ];
+            $this->assertSame($expected, error_get_last());
+        } catch (\Exception $e) {
+            restore_error_handler();
+            restore_exception_handler();
+
+            throw $e;
+        }
+    }
+
    public function testNotice()
    {
        ErrorHandler::register();

        try {
            self::triggerNotice($this);
-            $this->fail('ContextErrorException expected');
-        } catch (ContextErrorException $exception) {
+            $this->fail('ErrorException expected');
+        } catch (\ErrorException $exception) {
            // if an exception is thrown, the test passed
            $this->assertEquals(E_NOTICE, $exception->getSeverity());
            $this->assertEquals(__FILE__, $exception->getFile());
            $this->assertRegExp('/^Notice: Undefined variable: (foo|bar)/', $exception->getMessage());
-            $this->assertArrayHasKey('foobar', $exception->getContext());

            $trace = $exception->getTrace();

@@ -99,8 +125,6 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
    // dummy function to test trace in error handler.
    private static function triggerNotice($that)
    {
-        // dummy variable to check for in error handler.
-        $foobar = 123;
        $that->assertSame('', $foo.$foo.$bar);
    }

@@ -124,26 +148,26 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();

            $handler->setDefaultLogger($logger, E_NOTICE);
-            $handler->setDefaultLogger($logger, array(E_USER_NOTICE => LogLevel::CRITICAL));
+            $handler->setDefaultLogger($logger, [E_USER_NOTICE => LogLevel::CRITICAL]);

-            $loggers = array(
-                E_DEPRECATED => array(null, LogLevel::INFO),
-                E_USER_DEPRECATED => array(null, LogLevel::INFO),
-                E_NOTICE => array($logger, LogLevel::WARNING),
-                E_USER_NOTICE => array($logger, LogLevel::CRITICAL),
-                E_STRICT => array(null, LogLevel::WARNING),
-                E_WARNING => array(null, LogLevel::WARNING),
-                E_USER_WARNING => array(null, LogLevel::WARNING),
-                E_COMPILE_WARNING => array(null, LogLevel::WARNING),
-                E_CORE_WARNING => array(null, LogLevel::WARNING),
-                E_USER_ERROR => array(null, LogLevel::CRITICAL),
-                E_RECOVERABLE_ERROR => array(null, LogLevel::CRITICAL),
-                E_COMPILE_ERROR => array(null, LogLevel::CRITICAL),
-                E_PARSE => array(null, LogLevel::CRITICAL),
-                E_ERROR => array(null, LogLevel::CRITICAL),
-                E_CORE_ERROR => array(null, LogLevel::CRITICAL),
-            );
-            $this->assertSame($loggers, $handler->setLoggers(array()));
+            $loggers = [
+                E_DEPRECATED => [null, LogLevel::INFO],
+                E_USER_DEPRECATED => [null, LogLevel::INFO],
+                E_NOTICE => [$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_CORE_ERROR => [null, LogLevel::CRITICAL],
+            ];
+            $this->assertSame($loggers, $handler->setLoggers([]));
        } finally {
            restore_error_handler();
            restore_exception_handler();
@@ -155,14 +179,14 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        try {
            $handler = ErrorHandler::register();
            $handler->throwAt(0, true);
-            $this->assertFalse($handler->handleError(0, 'foo', 'foo.php', 12, array()));
+            $this->assertFalse($handler->handleError(0, 'foo', 'foo.php', 12, []));

            restore_error_handler();
            restore_exception_handler();

            $handler = ErrorHandler::register();
            $handler->throwAt(3, true);
-            $this->assertFalse($handler->handleError(4, 'foo', 'foo.php', 12, array()));
+            $this->assertFalse($handler->handleError(4, 'foo', 'foo.php', 12, []));

            restore_error_handler();
            restore_exception_handler();
@@ -170,7 +194,7 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
            $handler = ErrorHandler::register();
            $handler->throwAt(3, true);
            try {
-                $handler->handleError(4, 'foo', 'foo.php', 12, array());
+                $handler->handleError(4, 'foo', 'foo.php', 12, []);
            } catch (\ErrorException $e) {
                $this->assertSame('Parse Error: foo', $e->getMessage());
                $this->assertSame(4, $e->getSeverity());
@@ -183,14 +207,14 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase

            $handler = ErrorHandler::register();
            $handler->throwAt(E_USER_DEPRECATED, true);
-            $this->assertFalse($handler->handleError(E_USER_DEPRECATED, 'foo', 'foo.php', 12, array()));
+            $this->assertFalse($handler->handleError(E_USER_DEPRECATED, 'foo', 'foo.php', 12, []));

            restore_error_handler();
            restore_exception_handler();

            $handler = ErrorHandler::register();
            $handler->throwAt(E_DEPRECATED, true);
-            $this->assertFalse($handler->handleError(E_DEPRECATED, 'foo', 'foo.php', 12, array()));
+            $this->assertFalse($handler->handleError(E_DEPRECATED, 'foo', 'foo.php', 12, []));

            restore_error_handler();
            restore_exception_handler();
@@ -215,19 +239,24 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase

            $handler = ErrorHandler::register();
            $handler->setDefaultLogger($logger, E_USER_DEPRECATED);
-            $this->assertTrue($handler->handleError(E_USER_DEPRECATED, 'foo', 'foo.php', 12, array()));
+            $this->assertTrue($handler->handleError(E_USER_DEPRECATED, 'foo', 'foo.php', 12, []));

            restore_error_handler();
            restore_exception_handler();

            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();

-            $logArgCheck = function ($level, $message, $context) {
+            $line = null;
+            $logArgCheck = function ($level, $message, $context) use (&$line) {
                $this->assertEquals('Notice: Undefined variable: undefVar', $message);
                $this->assertArrayHasKey('exception', $context);
                $exception = $context['exception'];
                $this->assertInstanceOf(SilencedErrorContext::class, $exception);
                $this->assertSame(E_NOTICE, $exception->getSeverity());
+                $this->assertSame(__FILE__, $exception->getFile());
+                $this->assertSame($line, $exception->getLine());
+                $this->assertNotEmpty($exception->getTrace());
+                $this->assertSame(1, $exception->count);
            };

            $logger
@@ -240,6 +269,7 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
            $handler->setDefaultLogger($logger, E_NOTICE);
            $handler->screamAt(E_NOTICE);
            unset($undefVar);
+            $line = __LINE__ + 1;
            @$undefVar++;

            restore_error_handler();
@@ -293,9 +323,14 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase

        $handler = new ErrorHandler();
        $handler->setDefaultLogger($logger);
-        @$handler->handleError(E_USER_DEPRECATED, 'Foo deprecation', __FILE__, __LINE__, array());
+        @$handler->handleError(E_USER_DEPRECATED, 'Foo deprecation', __FILE__, __LINE__, []);
+
+        restore_error_handler();
    }

+    /**
+     * @group no-hhvm
+     */
    public function testHandleException()
    {
        try {
@@ -337,6 +372,9 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        }
    }

+    /**
+     * @group legacy
+     */
    public function testErrorStacking()
    {
        try {
@@ -349,12 +387,12 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
                ->expects($this->exactly(2))
                ->method('log')
                ->withConsecutive(
-                    array($this->equalTo(LogLevel::WARNING), $this->equalTo('Dummy log')),
-                    array($this->equalTo(LogLevel::DEBUG), $this->equalTo('User Warning: Silenced warning'))
+                    [$this->equalTo(LogLevel::WARNING), $this->equalTo('Dummy log')],
+                    [$this->equalTo(LogLevel::DEBUG), $this->equalTo('User Warning: Silenced warning')]
                )
            ;

-            $handler->setDefaultLogger($logger, array(E_USER_WARNING => LogLevel::WARNING));
+            $handler->setDefaultLogger($logger, [E_USER_WARNING => LogLevel::WARNING]);

            ErrorHandler::stackErrors();
            @trigger_error('Silenced warning', E_USER_WARNING);
@@ -371,27 +409,27 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        $bootLogger = new BufferingLogger();
        $handler = new ErrorHandler($bootLogger);

-        $loggers = array(
-            E_DEPRECATED => array($bootLogger, LogLevel::INFO),
-            E_USER_DEPRECATED => array($bootLogger, LogLevel::INFO),
-            E_NOTICE => array($bootLogger, LogLevel::WARNING),
-            E_USER_NOTICE => array($bootLogger, LogLevel::WARNING),
-            E_STRICT => array($bootLogger, LogLevel::WARNING),
-            E_WARNING => array($bootLogger, LogLevel::WARNING),
-            E_USER_WARNING => array($bootLogger, LogLevel::WARNING),
-            E_COMPILE_WARNING => array($bootLogger, LogLevel::WARNING),
-            E_CORE_WARNING => array($bootLogger, LogLevel::WARNING),
-            E_USER_ERROR => array($bootLogger, LogLevel::CRITICAL),
-            E_RECOVERABLE_ERROR => array($bootLogger, LogLevel::CRITICAL),
-            E_COMPILE_ERROR => array($bootLogger, LogLevel::CRITICAL),
-            E_PARSE => array($bootLogger, LogLevel::CRITICAL),
-            E_ERROR => array($bootLogger, LogLevel::CRITICAL),
-            E_CORE_ERROR => array($bootLogger, LogLevel::CRITICAL),
-        );
+        $loggers = [
+            E_DEPRECATED => [$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 => [$bootLogger, LogLevel::CRITICAL],
+            E_CORE_ERROR => [$bootLogger, LogLevel::CRITICAL],
+        ];

-        $this->assertSame($loggers, $handler->setLoggers(array()));
+        $this->assertSame($loggers, $handler->setLoggers([]));

-        $handler->handleError(E_DEPRECATED, 'Foo message', __FILE__, 123, array());
+        $handler->handleError(E_DEPRECATED, 'Foo message', __FILE__, 123, []);

        $logs = $bootLogger->cleanLogs();

@@ -407,16 +445,19 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        $this->assertSame(123, $exception->getLine());
        $this->assertSame(E_DEPRECATED, $exception->getSeverity());

-        $bootLogger->log(LogLevel::WARNING, 'Foo message', array('exception' => $exception));
+        $bootLogger->log(LogLevel::WARNING, 'Foo message', ['exception' => $exception]);

        $mockLogger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
        $mockLogger->expects($this->once())
            ->method('log')
-            ->with(LogLevel::WARNING, 'Foo message', array('exception' => $exception));
+            ->with(LogLevel::WARNING, 'Foo message', ['exception' => $exception]);

-        $handler->setLoggers(array(E_DEPRECATED => array($mockLogger, LogLevel::WARNING)));
+        $handler->setLoggers([E_DEPRECATED => [$mockLogger, LogLevel::WARNING]]);
    }

+    /**
+     * @group no-hhvm
+     */
    public function testSettingLoggerWhenExceptionIsBuffered()
    {
        $bootLogger = new BufferingLogger();
@@ -427,7 +468,7 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        $mockLogger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
        $mockLogger->expects($this->once())
            ->method('log')
-            ->with(LogLevel::CRITICAL, 'Uncaught Exception: Foo message', array('exception' => $exception));
+            ->with(LogLevel::CRITICAL, 'Uncaught Exception: Foo message', ['exception' => $exception]);

        $handler->setExceptionHandler(function () use ($handler, $mockLogger) {
            $handler->setDefaultLogger($mockLogger);
@@ -436,17 +477,20 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        $handler->handleException($exception);
    }

+    /**
+     * @group no-hhvm
+     */
    public function testHandleFatalError()
    {
        try {
            $handler = ErrorHandler::register();

-            $error = array(
+            $error = [
                'type' => E_PARSE,
                'message' => 'foo',
                'file' => 'bar',
                'line' => 123,
-            );
+            ];

            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();

@@ -485,7 +529,7 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase

        $handler = new ErrorHandler();
        $handler->setExceptionHandler(function () use (&$args) {
-            $args = func_get_args();
+            $args = \func_get_args();
        });

        $handler->handleException($exception);
@@ -494,6 +538,9 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
        $this->assertStringStartsWith("Attempted to load class \"Foo\" from the global namespace.\nDid you forget a \"use\" statement", $args[0]->getMessage());
    }

+    /**
+     * @group no-hhvm
+     */
    public function testHandleFatalErrorOnHHVM()
    {
        try {
@@ -511,20 +558,88 @@ class ErrorHandlerTest extends \PHPUnit_Framework_TestCase

            $handler->setDefaultLogger($logger, E_ERROR);

-            $error = array(
+            $error = [
                'type' => E_ERROR + 0x1000000, // This error level is used by HHVM for fatal errors
                'message' => 'foo',
                'file' => 'bar',
                'line' => 123,
-                'context' => array(123),
-                'backtrace' => array(456),
-            );
+                'context' => [123],
+                'backtrace' => [456],
+            ];

-            call_user_func_array(array($handler, 'handleError'), $error);
+            \call_user_func_array([$handler, 'handleError'], $error);
            $handler->handleFatalError($error);
        } finally {
            restore_error_handler();
            restore_exception_handler();
        }
    }
+
+    /**
+     * @expectedException \Exception
+     * @group no-hhvm
+     */
+    public function testCustomExceptionHandler()
+    {
+        $handler = new ErrorHandler();
+        $handler->setExceptionHandler(function ($e) use ($handler) {
+            $handler->handleException($e);
+        });
+
+        $handler->handleException(new \Exception());
+    }
+
+    /**
+     * @dataProvider errorHandlerWhenLoggingProvider
+     */
+    public function testErrorHandlerWhenLogging($previousHandlerWasDefined, $loggerSetsAnotherHandler, $nextHandlerIsDefined)
+    {
+        try {
+            if ($previousHandlerWasDefined) {
+                set_error_handler('count');
+            }
+
+            $logger = $loggerSetsAnotherHandler ? new LoggerThatSetAnErrorHandler() : new NullLogger();
+
+            $handler = ErrorHandler::register();
+            $handler->setDefaultLogger($logger);
+
+            if ($nextHandlerIsDefined) {
+                $handler = ErrorHandlerThatUsesThePreviousOne::register();
+            }
+
+            @trigger_error('foo', E_USER_DEPRECATED);
+            @trigger_error('bar', E_USER_DEPRECATED);
+
+            $this->assertSame([$handler, 'handleError'], set_error_handler('var_dump'));
+
+            if ($logger instanceof LoggerThatSetAnErrorHandler) {
+                $this->assertCount(2, $logger->cleanLogs());
+            }
+
+            restore_error_handler();
+
+            if ($previousHandlerWasDefined) {
+                restore_error_handler();
+            }
+
+            if ($nextHandlerIsDefined) {
+                restore_error_handler();
+            }
+        } finally {
+            restore_error_handler();
+            restore_exception_handler();
+        }
+    }
+
+    public function errorHandlerWhenLoggingProvider()
+    {
+        foreach ([false, true] as $previousHandlerWasDefined) {
+            foreach ([false, true] as $loggerSetsAnotherHandler) {
+                foreach ([false, true] as $nextHandlerIsDefined) {
+                    yield [$previousHandlerWasDefined, $loggerSetsAnotherHandler, $nextHandlerIsDefined];
+                }
+            }
+        }
+    }
 }
--- a/Tests/Exception/FlattenExceptionTest.php
+++ b/Tests/Exception/FlattenExceptionTest.php
@@ -11,23 +11,25 @@

 namespace Symfony\Component\Debug\Tests\Exception;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Debug\Exception\FlattenException;
-use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
-use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
-use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
-use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
-use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
-use Symfony\Component\HttpKernel\Exception\ConflictHttpException;
+use Symfony\Component\HttpFoundation\Exception\SuspiciousOperationException;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\ConflictHttpException;
 use Symfony\Component\HttpKernel\Exception\GoneHttpException;
 use Symfony\Component\HttpKernel\Exception\LengthRequiredHttpException;
+use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
+use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\HttpKernel\Exception\PreconditionFailedHttpException;
 use Symfony\Component\HttpKernel\Exception\PreconditionRequiredHttpException;
 use Symfony\Component\HttpKernel\Exception\ServiceUnavailableHttpException;
 use Symfony\Component\HttpKernel\Exception\TooManyRequestsHttpException;
+use Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException;
 use Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException;

-class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
+class FlattenExceptionTest extends TestCase
 {
    public function testStatusCode()
    {
@@ -52,7 +54,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
        $flattened = FlattenException::create(new ConflictHttpException());
        $this->assertEquals('409', $flattened->getStatusCode());

-        $flattened = FlattenException::create(new MethodNotAllowedHttpException(array('POST')));
+        $flattened = FlattenException::create(new MethodNotAllowedHttpException(['POST']));
        $this->assertEquals('405', $flattened->getStatusCode());

        $flattened = FlattenException::create(new AccessDeniedHttpException());
@@ -78,33 +80,38 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase

        $flattened = FlattenException::create(new UnsupportedMediaTypeHttpException());
        $this->assertEquals('415', $flattened->getStatusCode());
+
+        if (class_exists(SuspiciousOperationException::class)) {
+            $flattened = FlattenException::create(new SuspiciousOperationException());
+            $this->assertEquals('400', $flattened->getStatusCode());
+        }
    }

    public function testHeadersForHttpException()
    {
-        $flattened = FlattenException::create(new MethodNotAllowedHttpException(array('POST')));
-        $this->assertEquals(array('Allow' => 'POST'), $flattened->getHeaders());
+        $flattened = FlattenException::create(new MethodNotAllowedHttpException(['POST']));
+        $this->assertEquals(['Allow' => 'POST'], $flattened->getHeaders());

        $flattened = FlattenException::create(new UnauthorizedHttpException('Basic realm="My Realm"'));
-        $this->assertEquals(array('WWW-Authenticate' => 'Basic realm="My Realm"'), $flattened->getHeaders());
+        $this->assertEquals(['WWW-Authenticate' => 'Basic realm="My Realm"'], $flattened->getHeaders());

        $flattened = FlattenException::create(new ServiceUnavailableHttpException('Fri, 31 Dec 1999 23:59:59 GMT'));
-        $this->assertEquals(array('Retry-After' => 'Fri, 31 Dec 1999 23:59:59 GMT'), $flattened->getHeaders());
+        $this->assertEquals(['Retry-After' => 'Fri, 31 Dec 1999 23:59:59 GMT'], $flattened->getHeaders());

        $flattened = FlattenException::create(new ServiceUnavailableHttpException(120));
-        $this->assertEquals(array('Retry-After' => 120), $flattened->getHeaders());
+        $this->assertEquals(['Retry-After' => 120], $flattened->getHeaders());

        $flattened = FlattenException::create(new TooManyRequestsHttpException('Fri, 31 Dec 1999 23:59:59 GMT'));
-        $this->assertEquals(array('Retry-After' => 'Fri, 31 Dec 1999 23:59:59 GMT'), $flattened->getHeaders());
+        $this->assertEquals(['Retry-After' => 'Fri, 31 Dec 1999 23:59:59 GMT'], $flattened->getHeaders());

        $flattened = FlattenException::create(new TooManyRequestsHttpException(120));
-        $this->assertEquals(array('Retry-After' => 120), $flattened->getHeaders());
+        $this->assertEquals(['Retry-After' => 120], $flattened->getHeaders());
    }

    /**
     * @dataProvider flattenDataProvider
     */
-    public function testFlattenHttpException(\Exception $exception, $statusCode)
+    public function testFlattenHttpException(\Exception $exception)
    {
        $flattened = FlattenException::create($exception);
        $flattened2 = FlattenException::create($exception);
@@ -119,7 +126,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
    /**
     * @dataProvider flattenDataProvider
     */
-    public function testPrevious(\Exception $exception, $statusCode)
+    public function testPrevious(\Exception $exception)
    {
        $flattened = FlattenException::create($exception);
        $flattened2 = FlattenException::create($exception);
@@ -128,7 +135,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase

        $this->assertSame($flattened2, $flattened->getPrevious());

-        $this->assertSame(array($flattened2), $flattened->getAllPrevious());
+        $this->assertSame([$flattened2], $flattened->getAllPrevious());
    }

    /**
@@ -166,28 +173,28 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
    /**
     * @dataProvider flattenDataProvider
     */
-    public function testToArray(\Exception $exception, $statusCode)
+    public function testToArray(\Exception $exception)
    {
        $flattened = FlattenException::create($exception);
-        $flattened->setTrace(array(), 'foo.php', 123);
+        $flattened->setTrace([], 'foo.php', 123);

-        $this->assertEquals(array(
-            array(
+        $this->assertEquals([
+            [
                'message' => 'test',
                'class' => 'Exception',
-                'trace' => array(array(
+                'trace' => [[
                    'namespace' => '', 'short_class' => '', 'class' => '', 'type' => '', 'function' => '', 'file' => 'foo.php', 'line' => 123,
-                    'args' => array(),
-                )),
-            ),
-        ), $flattened->toArray());
+                    'args' => [],
+                ]],
+            ],
+        ], $flattened->toArray());
    }

    public function flattenDataProvider()
    {
-        return array(
-            array(new \Exception('test', 123), 500),
-        );
+        return [
+            [new \Exception('test', 123)],
+        ];
    }

    public function testArguments()
@@ -197,15 +204,15 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase

        $incomplete = unserialize('O:14:"BogusTestClass":0:{}');

-        $exception = $this->createException(array(
-            (object) array('foo' => 1),
+        $exception = $this->createException([
+            (object) ['foo' => 1],
            new NotFoundHttpException(),
            $incomplete,
            $dh,
            $fh,
            function () {},
-            array(1, 2),
-            array('foo' => 123),
+            [1, 2],
+            ['foo' => 123],
            null,
            true,
            false,
@@ -215,7 +222,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
            '',
            INF,
            NAN,
-        ));
+        ]);

        $flattened = FlattenException::create($exception);
        $trace = $flattened->getTrace();
@@ -226,26 +233,26 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
        fclose($fh);

        $i = 0;
-        $this->assertSame(array('object', 'stdClass'), $array[$i++]);
-        $this->assertSame(array('object', 'Symfony\Component\HttpKernel\Exception\NotFoundHttpException'), $array[$i++]);
-        $this->assertSame(array('incomplete-object', 'BogusTestClass'), $array[$i++]);
-        $this->assertSame(array('resource', defined('HHVM_VERSION') ? 'Directory' : 'stream'), $array[$i++]);
-        $this->assertSame(array('resource', 'stream'), $array[$i++]);
+        $this->assertSame(['object', 'stdClass'], $array[$i++]);
+        $this->assertSame(['object', 'Symfony\Component\HttpKernel\Exception\NotFoundHttpException'], $array[$i++]);
+        $this->assertSame(['incomplete-object', 'BogusTestClass'], $array[$i++]);
+        $this->assertSame(['resource', \defined('HHVM_VERSION') ? 'Directory' : 'stream'], $array[$i++]);
+        $this->assertSame(['resource', 'stream'], $array[$i++]);

        $args = $array[$i++];
        $this->assertSame($args[0], 'object');
        $this->assertTrue('Closure' === $args[1] || is_subclass_of($args[1], '\Closure'), 'Expect object class name to be Closure or a subclass of Closure.');

-        $this->assertSame(array('array', array(array('integer', 1), array('integer', 2))), $array[$i++]);
-        $this->assertSame(array('array', array('foo' => array('integer', 123))), $array[$i++]);
-        $this->assertSame(array('null', null), $array[$i++]);
-        $this->assertSame(array('boolean', true), $array[$i++]);
-        $this->assertSame(array('boolean', false), $array[$i++]);
-        $this->assertSame(array('integer', 0), $array[$i++]);
-        $this->assertSame(array('float', 0.0), $array[$i++]);
-        $this->assertSame(array('string', '0'), $array[$i++]);
-        $this->assertSame(array('string', ''), $array[$i++]);
-        $this->assertSame(array('float', INF), $array[$i++]);
+        $this->assertSame(['array', [['integer', 1], ['integer', 2]]], $array[$i++]);
+        $this->assertSame(['array', ['foo' => ['integer', 123]]], $array[$i++]);
+        $this->assertSame(['null', null], $array[$i++]);
+        $this->assertSame(['boolean', true], $array[$i++]);
+        $this->assertSame(['boolean', false], $array[$i++]);
+        $this->assertSame(['integer', 0], $array[$i++]);
+        $this->assertSame(['float', 0.0], $array[$i++]);
+        $this->assertSame(['string', '0'], $array[$i++]);
+        $this->assertSame(['string', ''], $array[$i++]);
+        $this->assertSame(['float', INF], $array[$i++]);

        // assertEquals() does not like NAN values.
        $this->assertEquals($array[$i][0], 'float');
@@ -254,7 +261,8 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase

    public function testRecursionInArguments()
    {
-        $a = array('foo', array(2, &$a));
+        $a = null;
+        $a = ['foo', [2, &$a]];
        $exception = $this->createException($a);

        $flattened = FlattenException::create($exception);
@@ -264,7 +272,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase

    public function testTooBigArray()
    {
-        $a = array();
+        $a = [];
        for ($i = 0; $i < 20; ++$i) {
            for ($j = 0; $j < 50; ++$j) {
                for ($k = 0; $k < 10; ++$k) {
@@ -279,7 +287,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
        $flattened = FlattenException::create($exception);
        $trace = $flattened->getTrace();

-        $this->assertSame($trace[1]['args'][0], array('array', array('array', '*SKIPPED over 10000 entries*')));
+        $this->assertSame($trace[1]['args'][0], ['array', ['array', '*SKIPPED over 10000 entries*']]);

        $serializeTrace = serialize($trace);

--- a/Tests/ExceptionHandlerTest.php
+++ b/Tests/ExceptionHandlerTest.php
@@ -11,14 +11,15 @@

 namespace Symfony\Component\Debug\Tests;

-use Symfony\Component\Debug\ExceptionHandler;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Debug\Exception\OutOfMemoryException;
-use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\Debug\ExceptionHandler;
 use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

 require_once __DIR__.'/HeaderMock.php';

-class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
+class ExceptionHandlerTest extends TestCase
 {
    protected function setUp()
    {
@@ -38,8 +39,8 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
        $handler->sendPhpResponse(new \RuntimeException('Foo'));
        $response = ob_get_clean();

-        $this->assertContains('<h1>Whoops, looks like something went wrong.</h1>', $response);
-        $this->assertNotContains('<h2 class="block_exception clear_fix">', $response);
+        $this->assertContains('Whoops, looks like something went wrong.', $response);
+        $this->assertNotContains('<div class="trace trace-as-html">', $response);

        $handler = new ExceptionHandler(true);

@@ -47,8 +48,8 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
        $handler->sendPhpResponse(new \RuntimeException('Foo'));
        $response = ob_get_clean();

-        $this->assertContains('<h1>Whoops, looks like something went wrong.</h1>', $response);
-        $this->assertContains('<h2 class="block_exception clear_fix">', $response);
+        $this->assertContains('Whoops, looks like something went wrong.', $response);
+        $this->assertContains('<div class="trace trace-as-html">', $response);
    }

    public function testStatusCode()
@@ -61,10 +62,10 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase

        $this->assertContains('Sorry, the page you are looking for could not be found.', $response);

-        $expectedHeaders = array(
-            array('HTTP/1.0 404', true, null),
-            array('Content-Type: text/html; charset=iso8859-1', true, null),
-        );
+        $expectedHeaders = [
+            ['HTTP/1.0 404', true, null],
+            ['Content-Type: text/html; charset=iso8859-1', true, null],
+        ];

        $this->assertSame($expectedHeaders, testHeader());
    }
@@ -74,14 +75,14 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
        $handler = new ExceptionHandler(false, 'iso8859-1');

        ob_start();
-        $handler->sendPhpResponse(new MethodNotAllowedHttpException(array('POST')));
+        $handler->sendPhpResponse(new MethodNotAllowedHttpException(['POST']));
        $response = ob_get_clean();

-        $expectedHeaders = array(
-            array('HTTP/1.0 405', true, null),
-            array('Allow: POST', false, null),
-            array('Content-Type: text/html; charset=iso8859-1', true, null),
-        );
+        $expectedHeaders = [
+            ['HTTP/1.0 405', true, null],
+            ['Allow: POST', false, null],
+            ['Content-Type: text/html; charset=iso8859-1', true, null],
+        ];

        $this->assertSame($expectedHeaders, testHeader());
    }
@@ -93,14 +94,14 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
        $handler->sendPhpResponse(new \RuntimeException('Foo', 0, new \RuntimeException('Bar')));
        $response = ob_get_clean();

-        $this->assertStringMatchesFormat('%A<span class="exception_message">Foo</span>%A<span class="exception_message">Bar</span>%A', $response);
+        $this->assertStringMatchesFormat('%A<p class="break-long-words trace-message">Foo</p>%A<p class="break-long-words trace-message">Bar</p>%A', $response);
    }

    public function testHandle()
    {
        $exception = new \Exception('foo');

-        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(array('sendPhpResponse'))->getMock();
+        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
        $handler
            ->expects($this->exactly(2))
            ->method('sendPhpResponse');
@@ -118,7 +119,7 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
    {
        $exception = new OutOfMemoryException('foo', 0, E_ERROR, __FILE__, __LINE__);

-        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(array('sendPhpResponse'))->getMock();
+        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
        $handler
            ->expects($this->once())
            ->method('sendPhpResponse');
--- a/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
+++ b/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
@@ -11,18 +11,18 @@

 namespace Symfony\Component\Debug\Tests\FatalErrorHandler;

-use Symfony\Component\Debug\Exception\FatalErrorException;
-use Symfony\Component\ClassLoader\ClassLoader as SymfonyClassLoader;
-use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
-use Symfony\Component\Debug\DebugClassLoader;
 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;

-class ClassNotFoundFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase
+class ClassNotFoundFatalErrorHandlerTest extends TestCase
 {
    public static function setUpBeforeClass()
    {
        foreach (spl_autoload_functions() as $function) {
-            if (!is_array($function)) {
+            if (!\is_array($function)) {
                continue;
            }

@@ -32,7 +32,7 @@ class ClassNotFoundFatalErrorHandlerTest extends \PHPUnit_Framework_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_Debug_Tests_Fixtures', \dirname(\dirname(\dirname(\dirname(\dirname(__DIR__))))));
                break;
            }
        }
@@ -69,90 +69,88 @@ class ClassNotFoundFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase

    public function provideClassNotFoundData()
    {
-        $prefixes = array('Symfony\Component\Debug\Exception\\' => realpath(__DIR__.'/../../Exception'));
+        $autoloader = new ComposerClassLoader();
+        $autoloader->add('Symfony\Component\Debug\Exception\\', realpath(__DIR__.'/../../Exception'));

-        $symfonyAutoloader = new SymfonyClassLoader();
-        $symfonyAutoloader->addPrefixes($prefixes);
+        $debugClassLoader = new DebugClassLoader([$autoloader, 'loadClass']);

-        $debugClassLoader = new DebugClassLoader(array($symfonyAutoloader, 'loadClass'));
-
-        return array(
-            array(
-                array(
+        return [
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Class \'WhizBangFactory\' not found',
-                ),
+                ],
                "Attempted to load class \"WhizBangFactory\" from the global namespace.\nDid you forget a \"use\" statement?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Class \'Foo\\Bar\\WhizBangFactory\' not found',
-                ),
+                ],
                "Attempted to load class \"WhizBangFactory\" from namespace \"Foo\\Bar\".\nDid you forget a \"use\" statement for another namespace?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Class \'UndefinedFunctionException\' not found',
-                ),
+                ],
                "Attempted to load class \"UndefinedFunctionException\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    '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\"?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    '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\"?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    '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\"?",
-                array($symfonyAutoloader, 'loadClass'),
-            ),
-            array(
-                array(
+                [$autoloader, 'loadClass'],
+            ],
+            [
+                [
                    '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\"?",
-                array($debugClassLoader, 'loadClass'),
-            ),
-            array(
-                array(
+                [$debugClassLoader, 'loadClass'],
+            ],
+            [
+                [
                    '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 another namespace?",
                function ($className) { /* do nothing here */ },
-            ),
-        );
+            ],
+        ];
    }

    public function testCannotRedeclareClass()
@@ -163,12 +161,12 @@ class ClassNotFoundFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase

        require_once __DIR__.'/../FIXTURES2/REQUIREDTWICE.PHP';

-        $error = array(
+        $error = [
            'type' => 1,
            'line' => 12,
            'file' => 'foo.php',
            'message' => 'Class \'Foo\\Bar\\RequiredTwice\' not found',
-        );
+        ];

        $handler = new ClassNotFoundFatalErrorHandler();
        $exception = $handler->handleError($error, new FatalErrorException('', 0, $error['type'], $error['file'], $error['line']));
--- a/Tests/FatalErrorHandler/UndefinedFunctionFatalErrorHandlerTest.php
+++ b/Tests/FatalErrorHandler/UndefinedFunctionFatalErrorHandlerTest.php
@@ -11,10 +11,11 @@

 namespace Symfony\Component\Debug\Tests\FatalErrorHandler;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Debug\Exception\FatalErrorException;
 use Symfony\Component\Debug\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;

-class UndefinedFunctionFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase
+class UndefinedFunctionFatalErrorHandlerTest extends TestCase
 {
    /**
     * @dataProvider provideUndefinedFunctionData
@@ -34,44 +35,44 @@ class UndefinedFunctionFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase

    public function provideUndefinedFunctionData()
    {
-        return array(
-            array(
-                array(
+        return [
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    '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\"?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    '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\"?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Call to undefined function foo()',
-                ),
+                ],
                'Attempted to call function "foo" from the global namespace.',
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Call to undefined function Foo\\Bar\\Baz\\foo()',
-                ),
+                ],
                'Attempted to call function "foo" from namespace "Foo\Bar\Baz".',
-            ),
-        );
+            ],
+        ];
    }
 }

--- a/Tests/FatalErrorHandler/UndefinedMethodFatalErrorHandlerTest.php
+++ b/Tests/FatalErrorHandler/UndefinedMethodFatalErrorHandlerTest.php
@@ -11,10 +11,11 @@

 namespace Symfony\Component\Debug\Tests\FatalErrorHandler;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Debug\Exception\FatalErrorException;
 use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;

-class UndefinedMethodFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase
+class UndefinedMethodFatalErrorHandlerTest extends TestCase
 {
    /**
     * @dataProvider provideUndefinedMethodData
@@ -33,43 +34,43 @@ class UndefinedMethodFatalErrorHandlerTest extends \PHPUnit_Framework_TestCase

    public function provideUndefinedMethodData()
    {
-        return array(
-            array(
-                array(
+        return [
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Call to undefined method SplObjectStorage::what()',
-                ),
+                ],
                'Attempted to call an undefined method named "what" of class "SplObjectStorage".',
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Call to undefined method SplObjectStorage::walid()',
-                ),
+                ],
                "Attempted to call an undefined method named \"walid\" of class \"SplObjectStorage\".\nDid you mean to call \"valid\"?",
-            ),
-            array(
-                array(
+            ],
+            [
+                [
                    'type' => 1,
                    'line' => 12,
                    'file' => 'foo.php',
                    'message' => 'Call to undefined method SplObjectStorage::offsetFet()',
-                ),
+                ],
                "Attempted to call an undefined method named \"offsetFet\" of class \"SplObjectStorage\".\nDid you mean to call e.g. \"offsetGet\", \"offsetSet\" or \"offsetUnset\"?",
-            ),
-            array(
-                array(
-                  'type' => 1,
-                  'message' => 'Call to undefined method class@anonymous::test()',
-                  'file' => '/home/possum/work/symfony/test.php',
-                  'line' => 11,
-                ),
+            ],
+            [
+                [
+                    'type' => 1,
+                    'message' => 'Call to undefined method class@anonymous::test()',
+                    'file' => '/home/possum/work/symfony/test.php',
+                    'line' => 11,
+                ],
                'Attempted to call an undefined method named "test" of class "class@anonymous".',
-            ),
-        );
+            ],
+        ];
    }
 }
--- a/Tests/Fixtures/AnnotatedClass.php
+++ b/Tests/Fixtures/AnnotatedClass.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class AnnotatedClass
+{
+    /**
+     * @deprecated since version 3.4.
+     */
+    public function deprecatedMethod()
+    {
+    }
+}
--- a/Tests/Fixtures/DefinitionInEvaluatedCode.php
+++ b/Tests/Fixtures/DefinitionInEvaluatedCode.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+eval('
+    namespace Symfony\Component\Debug\Tests\Fixtures;
+
+    class DefinitionInEvaluatedCode
+    {
+    }
+');
--- a/Tests/Fixtures/DeprecatedClass.php
+++ b/Tests/Fixtures/DeprecatedClass.php
@@ -4,7 +4,7 @@ namespace Symfony\Component\Debug\Tests\Fixtures;

 /**
 * @deprecated but this is a test
- *             deprecation notice.
+ *             deprecation notice
 * @foobar
 */
 class DeprecatedClass
--- a/Tests/Fixtures/DeprecatedInterface.php
+++ b/Tests/Fixtures/DeprecatedInterface.php
@@ -4,7 +4,7 @@ namespace Symfony\Component\Debug\Tests\Fixtures;

 /**
 * @deprecated but this is a test
- *             deprecation notice.
+ *             deprecation notice
 * @foobar
 */
 interface DeprecatedInterface
--- a/Tests/Fixtures/ErrorHandlerThatUsesThePreviousOne.php
+++ b/Tests/Fixtures/ErrorHandlerThatUsesThePreviousOne.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class ErrorHandlerThatUsesThePreviousOne
+{
+    private static $previous;
+
+    public static function register()
+    {
+        $handler = new static();
+
+        self::$previous = set_error_handler([$handler, 'handleError']);
+
+        return $handler;
+    }
+
+    public function handleError($type, $message, $file, $line, $context)
+    {
+        return \call_user_func(self::$previous, $type, $message, $file, $line, $context);
+    }
+}
--- a/Tests/Fixtures/ExtendedFinalMethod.php
+++ b/Tests/Fixtures/ExtendedFinalMethod.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class ExtendedFinalMethod extends FinalMethod
+{
+    use FinalMethod2Trait;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function finalMethod()
+    {
+    }
+
+    public function anotherMethod()
+    {
+    }
+}
--- a/Tests/Fixtures/FinalClasses.php
+++ b/Tests/Fixtures/FinalClasses.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @final since version 3.3.
+ */
+class FinalClass1
+{
+    // simple comment
+}
+
+/**
+ * @final
+ */
+class FinalClass2
+{
+    // no comment
+}
+
+/**
+ * @final comment with @@@ and ***
+ *
+ * @author John Doe
+ */
+class FinalClass3
+{
+    // with comment and a tag after
+}
+
+/**
+ * @final
+ * @author John Doe
+ */
+class FinalClass4
+{
+    // without comment and a tag after
+}
+
+/**
+ * @author John Doe
+ *
+ *
+ * @final multiline
+ * comment
+ */
+class FinalClass5
+{
+    // with comment and a tag before
+}
+
+/**
+ * @author John Doe
+ *
+ * @final
+ */
+class FinalClass6
+{
+    // without comment and a tag before
+}
+
+/**
+ * @author John Doe
+ *
+ * @final another
+ *
+ *        multiline comment...
+ *
+ * @return string
+ */
+class FinalClass7
+{
+    // with comment and a tag before and after
+}
+
+/**
+ * @author John Doe
+ * @final
+ * @return string
+ */
+class FinalClass8
+{
+    // without comment and a tag before and after
+}
--- a/Tests/Fixtures/FinalMethod.php
+++ b/Tests/Fixtures/FinalMethod.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class FinalMethod
+{
+    /**
+     * @final since version 3.3.
+     */
+    public function finalMethod()
+    {
+    }
+
+    /**
+     * @final
+     */
+    public function finalMethod2()
+    {
+    }
+
+    public function anotherMethod()
+    {
+    }
+}
--- a/Tests/Fixtures/FinalMethod2Trait.php
+++ b/Tests/Fixtures/FinalMethod2Trait.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+trait FinalMethod2Trait
+{
+    public function finalMethod2()
+    {
+    }
+}
--- a/Tests/Fixtures/InternalClass.php
+++ b/Tests/Fixtures/InternalClass.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @internal since version 3.4.
+ */
+class InternalClass
+{
+    use InternalTrait2;
+
+    public function usedInInternalClass()
+    {
+    }
+}
--- a/Tests/Fixtures/InternalInterface.php
+++ b/Tests/Fixtures/InternalInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @internal
+ */
+interface InternalInterface
+{
+}
--- a/Tests/Fixtures/InternalTrait.php
+++ b/Tests/Fixtures/InternalTrait.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @internal
+ */
+trait InternalTrait
+{
+}
--- a/Tests/Fixtures/InternalTrait2.php
+++ b/Tests/Fixtures/InternalTrait2.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @internal
+ */
+trait InternalTrait2
+{
+    /**
+     * @internal since version 3.4
+     */
+    public function internalMethod()
+    {
+    }
+
+    /**
+     * @internal but should not trigger a deprecation
+     */
+    public function usedInInternalClass()
+    {
+    }
+}
--- a/Tests/Fixtures/LoggerThatSetAnErrorHandler.php
+++ b/Tests/Fixtures/LoggerThatSetAnErrorHandler.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+use Symfony\Component\Debug\BufferingLogger;
+
+class LoggerThatSetAnErrorHandler extends BufferingLogger
+{
+    public function log($level, $message, array $context = [])
+    {
+        set_error_handler('is_string');
+        parent::log($level, $message, $context);
+        restore_error_handler();
+    }
+}
--- a/Tests/Fixtures/Throwing.php
+++ b/Tests/Fixtures/Throwing.php
@@ -0,0 +1,3 @@
+<?php
+
+throw new \Exception('boo');
--- a/Tests/Fixtures/ToStringThrower.php
+++ b/Tests/Fixtures/ToStringThrower.php
@@ -18,7 +18,7 @@ class ToStringThrower
        } catch (\Exception $e) {
            // Using user_error() here is on purpose so we do not forget
            // that this alias also should work alongside with trigger_error().
-            return user_error($e, E_USER_ERROR);
+            return trigger_error($e, E_USER_ERROR);
        }
    }
 }
--- a/Tests/Fixtures/TraitWithInternalMethod.php
+++ b/Tests/Fixtures/TraitWithInternalMethod.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+trait TraitWithInternalMethod
+{
+    /**
+     * @internal
+     */
+    public function foo()
+    {
+    }
+}
--- a/Tests/HeaderMock.php
+++ b/Tests/HeaderMock.php
@@ -25,14 +25,14 @@ namespace Symfony\Component\Debug\Tests;

 function testHeader()
 {
-    static $headers = array();
+    static $headers = [];

-    if (!$h = func_get_args()) {
+    if (!$h = \func_get_args()) {
        $h = $headers;
-        $headers = array();
+        $headers = [];

        return $h;
    }

-    $headers[] = func_get_args();
+    $headers[] = \func_get_args();
 }
--- a/Tests/phpt/debug_class_loader.phpt
+++ b/Tests/phpt/debug_class_loader.phpt
@@ -0,0 +1,27 @@
+--TEST--
+Test DebugClassLoader with previously loaded parents
+--FILE--
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+use Symfony\Component\Debug\DebugClassLoader;
+
+$vendor = __DIR__;
+while (!file_exists($vendor.'/vendor')) {
+    $vendor = \dirname($vendor);
+}
+require $vendor.'/vendor/autoload.php';
+
+class_exists(FinalMethod::class);
+
+set_error_handler(function ($type, $msg) { echo $msg, "\n"; });
+
+DebugClassLoader::enable();
+
+class_exists(ExtendedFinalMethod::class);
+
+?>
+--EXPECTF--
+The "Symfony\Component\Debug\Tests\Fixtures\FinalMethod::finalMethod()" method is considered final since version 3.3. It may change without further notice as of its next major version. You should not extend it from "Symfony\Component\Debug\Tests\Fixtures\ExtendedFinalMethod".
+The "Symfony\Component\Debug\Tests\Fixtures\FinalMethod::finalMethod2()" method is considered final. It may change without further notice as of its next major version. You should not extend it from "Symfony\Component\Debug\Tests\Fixtures\ExtendedFinalMethod".
--- a/Tests/phpt/decorate_exception_hander.phpt
+++ b/Tests/phpt/decorate_exception_hander.phpt
@@ -0,0 +1,47 @@
+--TEST--
+Test catching fatal errors when handlers are nested
+--INI--
+display_errors=0
+--FILE--
+<?php
+
+namespace Symfony\Component\Debug;
+
+$vendor = __DIR__;
+while (!file_exists($vendor.'/vendor')) {
+    $vendor = \dirname($vendor);
+}
+require $vendor.'/vendor/autoload.php';
+
+set_error_handler('var_dump');
+set_exception_handler('var_dump');
+
+ErrorHandler::register(null, false);
+
+if (true) {
+    class foo extends missing
+    {
+    }
+}
+
+?>
+--EXPECTF--
+object(Symfony\Component\Debug\Exception\ClassNotFoundException)#%d (8) {
+  ["message":protected]=>
+  string(131) "Attempted to load class "missing" from namespace "Symfony\Component\Debug".
+Did you forget a "use" statement for another namespace?"
+  ["string":"Exception":private]=>
+  string(0) ""
+  ["code":protected]=>
+  int(0)
+  ["file":protected]=>
+  string(%d) "%s"
+  ["line":protected]=>
+  int(%d)
+  ["trace":"Exception":private]=>
+  array(%d) {%A}
+  ["previous":"Exception":private]=>
+  NULL
+  ["severity":protected]=>
+  int(1)
+}
--- a/Tests/phpt/exception_rethrown.phpt
+++ b/Tests/phpt/exception_rethrown.phpt
@@ -0,0 +1,35 @@
+--TEST--
+Test rethrowing in custom exception handler
+--FILE--
+<?php
+
+namespace Symfony\Component\Debug;
+
+$vendor = __DIR__;
+while (!file_exists($vendor.'/vendor')) {
+    $vendor = \dirname($vendor);
+}
+require $vendor.'/vendor/autoload.php';
+
+if (true) {
+    class TestLogger extends \Psr\Log\AbstractLogger
+    {
+        public function log($level, $message, array $context = [])
+        {
+            echo $message, "\n";
+        }
+    }
+}
+
+set_exception_handler(function ($e) { echo 123; throw $e; });
+ErrorHandler::register()->setDefaultLogger(new TestLogger());
+ini_set('display_errors', 1);
+
+throw new \Exception('foo');
+?>
+--EXPECTF--
+Uncaught Exception: foo
+123
+Fatal error: Uncaught %s:25
+Stack trace:
+%a
--- a/Tests/phpt/fatal_with_nested_handlers.phpt
+++ b/Tests/phpt/fatal_with_nested_handlers.phpt
@@ -0,0 +1,42 @@
+--TEST--
+Test catching fatal errors when handlers are nested
+--FILE--
+<?php
+
+namespace Symfony\Component\Debug;
+
+$vendor = __DIR__;
+while (!file_exists($vendor.'/vendor')) {
+    $vendor = \dirname($vendor);
+}
+require $vendor.'/vendor/autoload.php';
+
+Debug::enable();
+ini_set('display_errors', 0);
+
+$eHandler = set_error_handler('var_dump');
+$xHandler = set_exception_handler('var_dump');
+
+var_dump([
+    $eHandler[0] === $xHandler[0] ? 'Error and exception handlers do match' : 'Error and exception handlers are different',
+]);
+
+$eHandler[0]->setExceptionHandler('print_r');
+
+if (true) {
+    class Broken implements \Serializable
+    {
+    }
+}
+
+?>
+--EXPECTF--
+array(1) {
+  [0]=>
+  string(37) "Error and exception handlers do match"
+}
+object(Symfony\Component\Debug\Exception\FatalErrorException)#%d (%d) {
+  ["message":protected]=>
+  string(199) "Error: Class Symfony\Component\Debug\Broken contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (Serializable::serialize, Serializable::unserialize)"
+%a
+}
--- a/composer.json
+++ b/composer.json
@@ -16,15 +16,14 @@
        }
    ],
    "require": {
-        "php": ">=5.5.9",
+        "php": "^5.5.9|>=7.0.8",
        "psr/log": "~1.0"
    },
    "conflict": {
        "symfony/http-kernel": ">=2.3,<2.3.24|~2.4.0|>=2.5,<2.5.9|>=2.6,<2.6.2"
    },
    "require-dev": {
-        "symfony/class-loader": "~2.8|~3.0",
-        "symfony/http-kernel": "~2.8|~3.0"
+        "symfony/http-kernel": "~2.8|~3.0|~4.0"
    },
    "autoload": {
        "psr-4": { "Symfony\\Component\\Debug\\": "" },
@@ -35,7 +34,7 @@
    "minimum-stability": "dev",
    "extra": {
        "branch-alias": {
-            "dev-master": "3.2-dev"
+            "dev-master": "3.4-dev"
        }
    }
 }
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,10 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>

 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.1/phpunit.xsd"
+         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" />