Check headers sent before sending PHP response

If the response contents has been sent before an error occurs, PHP
triggers the warning "Cannot modify header information - headers already sent"

This change ensure that the error message is echoed, while it's impossible
to change the HTTP status code and headers.

ErrorHandler.php

@@ -142,10 +142,10 @@ class ErrorHandler
 
                 // we must stop the PHP script execution, as the exception has
                 // already been dealt with, so, let's throw an exception that
-                // will be catched by a dummy exception handler
+                // will be caught by a dummy exception handler
                 set_exception_handler(function (\Exception $e) use ($exceptionHandler) {
                     if (!$e instanceof DummyException) {
-                        // happens if our dummy exception is catched by a
+                        // happens if our dummy exception is caught by a
                         // catch-all from user code, in which case, let's the
                         // current handler handle this "new" exception
                         call_user_func($exceptionHandler, $e);
@@ -186,7 +186,7 @@ class ErrorHandler
         }
 
         // get current exception handler
-        $exceptionHandler = set_exception_handler(function() {});
+        $exceptionHandler = set_exception_handler(function () {});
         restore_exception_handler();
 
         if (is_array($exceptionHandler) && $exceptionHandler[0] instanceof ExceptionHandler) {

Exception/FlattenException.php

@@ -249,7 +249,7 @@ class FlattenException
                 if ($level > 10) {
                     $result[$key] = array('array', '*DEEP NESTED ARRAY*');
                 } else {
-                    $result[$key] = array('array', $this->flattenArgs($value, ++$level));
+                    $result[$key] = array('array', $this->flattenArgs($value, $level + 1));
                 }
             } elseif (null === $value) {
                 $result[$key] = array('null', null);

ExceptionHandler.php

@@ -91,9 +91,11 @@ class ExceptionHandler
             $exception = FlattenException::create($exception);
         }
 
-        header(sprintf('HTTP/1.0 %s', $exception->getStatusCode()));
-        foreach ($exception->getHeaders() as $name => $value) {
-            header($name.': '.$value, false);
+        if (!headers_sent()) {
+            header(sprintf('HTTP/1.0 %s', $exception->getStatusCode()));
+            foreach ($exception->getHeaders() as $name => $value) {
+                header($name.': '.$value, false);
+            }
         }
 
         echo $this->decorate($this->getContent($exception), $this->getStylesheet($exception));

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2004-2013 Fabien Potencier
+Copyright (c) 2004-2014 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

Tests/ErrorHandlerTest.php

@@ -104,7 +104,7 @@ PHP
         set_exception_handler(array($exceptionHandler, 'handle'));
 
         $that = $this;
-        $exceptionCheck = function($exception) use ($that) {
+        $exceptionCheck = function ($exception) use ($that) {
             $that->assertInstanceOf('Symfony\Component\Debug\Exception\ContextErrorException', $exception);
             $that->assertEquals(E_NOTICE, $exception->getSeverity());
             $that->assertEquals(__LINE__ + 40, $exception->getLine());
@@ -199,7 +199,7 @@ PHP
         $logger = $this->getMock('Psr\Log\LoggerInterface');
 
         $that = $this;
-        $warnArgCheck = function($message, $context) use ($that) {
+        $warnArgCheck = function ($message, $context) use ($that) {
             $that->assertEquals('foo', $message);
             $that->assertArrayHasKey('type', $context);
             $that->assertEquals($context['type'], ErrorHandler::TYPE_DEPRECATION);

Tests/Exception/FlattenExceptionTest.php

@@ -113,7 +113,7 @@ class FlattenExceptionTest extends \PHPUnit_Framework_TestCase
 
         $this->assertEquals($exception->getMessage(), $flattened->getMessage(), 'The message is copied from the original exception.');
         $this->assertEquals($exception->getCode(), $flattened->getCode(), 'The code is copied from the original exception.');
-        $this->assertEquals(get_class($exception), $flattened->getClass(), 'The class is set to the class of the original exception');
+        $this->assertInstanceOf($flattened->getClass(), $exception, 'The class is set to the class of the original exception');
 
     }
 

Tests/ExceptionHandlerTest.php

@@ -64,6 +64,6 @@ class ExceptionHandlerTest extends \PHPUnit_Framework_TestCase
     public function testNestedExceptions()
     {
         $handler = new ExceptionHandler(true);
-        $response = $handler->createResponse(new \RuntimeException('Foo', null, new \RuntimeException('Bar')));
+        $response = $handler->createResponse(new \RuntimeException('Foo', 0, new \RuntimeException('Bar')));
     }
 }