[Debug] Tell that the extension is for PHP 5 only

```
php > echo (E_ALL | E_STRICT) & (0 | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
4352
php > echo (0 | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
4352
php > echo (2 | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
4354
```

DebugClassLoader.php

@@ -224,7 +224,7 @@ class DebugClassLoader
                 $i = count($tail) - 1;
                 $j = count($real) - 1;
 
-                 while (isset($tail[$i], $real[$j]) && $tail[$i] === $real[$j]) {
+                while (isset($tail[$i], $real[$j]) && $tail[$i] === $real[$j]) {
                     --$i;
                     --$j;
                 }

ErrorHandler.php

@@ -95,6 +95,7 @@ class ErrorHandler
 
     private $loggedTraces = array();
     private $isRecursive = 0;
+    private $isRoot = false;
     private $exceptionHandler;
 
     private static $reservedMemory;
@@ -134,7 +135,12 @@ class ErrorHandler
             $handler = new static();
         }
 
-        $prev = set_error_handler(array($handler, 'handleError'), $handler->thrownErrors | $handler->loggedErrors);
+        if (null === $prev = set_error_handler(array($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);
+            $handler->isRoot = true;
+        }
 
         if ($handlerIsNew && is_array($prev) && $prev[0] instanceof self) {
             $handler = $prev[0];
@@ -251,7 +257,7 @@ class ErrorHandler
     public function throwAt($levels, $replace = false)
     {
         $prev = $this->thrownErrors;
-        $this->thrownErrors = (E_ALL | E_STRICT) & ($levels | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
+        $this->thrownErrors = ($levels | E_RECOVERABLE_ERROR | E_USER_ERROR) & ~E_USER_DEPRECATED & ~E_DEPRECATED;
         if (!$replace) {
             $this->thrownErrors |= $prev;
         }
@@ -326,12 +332,16 @@ class ErrorHandler
     private function reRegister($prev)
     {
         if ($prev !== $this->thrownErrors | $this->loggedErrors) {
-            $handler = set_error_handler('var_dump', 0);
+            $handler = set_error_handler('var_dump');
             $handler = is_array($handler) ? $handler[0] : null;
             restore_error_handler();
             if ($handler === $this) {
                 restore_error_handler();
-                set_error_handler(array($this, 'handleError'), $this->thrownErrors | $this->loggedErrors);
+                if ($this->isRoot) {
+                    set_error_handler(array($this, 'handleError'), $this->thrownErrors | $this->loggedErrors);
+                } else {
+                    set_error_handler(array($this, 'handleError'));
+                }
             }
         }
     }
@@ -527,7 +537,7 @@ class ErrorHandler
 
         self::$reservedMemory = null;
 
-        $handler = set_error_handler('var_dump', 0);
+        $handler = set_error_handler('var_dump');
         $handler = is_array($handler) ? $handler[0] : null;
         restore_error_handler();
 
@@ -672,7 +682,7 @@ class ErrorHandler
     {
         @trigger_error('The '.__METHOD__.' static method is deprecated since version 2.6 and will be removed in 3.0. Use the setLoggers() or setDefaultLogger() methods instead.', E_USER_DEPRECATED);
 
-        $handler = set_error_handler('var_dump', 0);
+        $handler = set_error_handler('var_dump');
         $handler = is_array($handler) ? $handler[0] : null;
         restore_error_handler();
         if (!$handler instanceof self) {

Exception/FlattenException.php

@@ -94,8 +94,13 @@ class FlattenException extends LegacyFlattenException
         $e->setClass(get_class($exception));
         $e->setFile($exception->getFile());
         $e->setLine($exception->getLine());
-        if ($exception->getPrevious()) {
-            $e->setPrevious(static::create($exception->getPrevious()));
+
+        $previous = $exception->getPrevious();
+
+        if ($previous instanceof \Exception) {
+            $e->setPrevious(static::create($previous));
+        } elseif ($previous instanceof \Throwable) {
+            $e->setPrevious(static::create(new FatalThrowableError($previous)));
         }
 
         return $e;

ExceptionHandler.php

@@ -238,7 +238,7 @@ class ExceptionHandler
                     $ind = $count - $position + 1;
                     $class = $this->formatClass($e['class']);
                     $message = nl2br($this->escapeHtml($e['message']));
-                    $content .= sprintf(<<<EOF
+                    $content .= sprintf(<<<'EOF'
                         <h2 class="block_exception clear_fix">
                             <span class="exception_counter">%d/%d</span>
                             <span class="exception_title">%s%s:</span>
@@ -289,7 +289,7 @@ EOF;
      */
     public function getStylesheet(FlattenException $exception)
     {
-        return <<<EOF
+        return <<<'EOF'
             .sf-reset { font: 11px Verdana, Arial, sans-serif; color: #333 }
             .sf-reset .clear { clear:both; height:0; font-size:0; line-height:0; }
             .sf-reset .clear_fix:after { display:block; height:0; clear:both; visibility:hidden; }

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2004-2015 Fabien Potencier
+Copyright (c) 2004-2016 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

Resources/ext/README.md

@@ -1,7 +1,9 @@
-Symfony Debug Extension
-=======================
+Symfony Debug Extension for PHP 5
+=================================
 
 This extension publishes several functions to help building powerful debugging tools.
+It is compatible with PHP 5.3, 5.4, 5.5 and 5.6; with ZTS and non-ZTS modes.
+It is not required thus not provided for PHP 7.
 
 symfony_zval_info()
 -------------------
@@ -122,7 +124,6 @@ array(3) {
 Usage
 -----
 
-The extension is compatible with ZTS mode, and should be supported by PHP5.3, 5.4, 5.5 and 5.6.
 To enable the extension from source, run:
 
 ```

Tests/DebugClassLoaderTest.php

@@ -175,7 +175,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
      */
     public function testDeprecatedSuper($class, $super, $type)
     {
-        set_error_handler('var_dump', 0);
+        set_error_handler(function () { return false; });
         $e = error_reporting(0);
         trigger_error('', E_USER_DEPRECATED);
 
@@ -205,7 +205,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
 
     public function testDeprecatedSuperInSameNamespace()
     {
-        set_error_handler('var_dump', 0);
+        set_error_handler(function () { return false; });
         $e = error_reporting(0);
         trigger_error('', E_USER_NOTICE);
 
@@ -231,7 +231,7 @@ class DebugClassLoaderTest extends \PHPUnit_Framework_TestCase
             $this->markTestSkipped('PHP7 already prevents using reserved names.');
         }
 
-        set_error_handler('var_dump', 0);
+        set_error_handler(function () { return false; });
         $e = error_reporting(0);
         trigger_error('', E_USER_NOTICE);
 

Tests/Exception/FlattenExceptionTest.php

@@ -131,6 +131,20 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
         $this->assertSame(array($flattened2), $flattened->getAllPrevious());
     }
 
+    /**
+     * @requires PHP 7.0
+     */
+    public function testPreviousError()
+    {
+        $exception = new \Exception('test', 123, new \ParseError('Oh noes!', 42));
+
+        $flattened = FlattenException::create($exception)->getPrevious();
+
+        $this->assertEquals($flattened->getMessage(), 'Parse error: Oh noes!', 'The message is copied from the original exception.');
+        $this->assertEquals($flattened->getCode(), 42, 'The code is copied from the original exception.');
+        $this->assertEquals($flattened->getClass(), 'Symfony\Component\Debug\Exception\FatalThrowableError', 'The class is set to the class of the original exception');
+    }
+
     /**
      * @dataProvider flattenDataProvider
      */