More on error handling:

- Correct exit code for require errors in CLI mode. It was 0 even in case of error.
- Solved handling fatals and displaying custom error template w/o output buffering.
- If XDEBUG is available, error screen will display trace (implementation inspired by Kohana and Nette).
- Added ErrorException to store/display type of the error and user-friendly messages.
- Fatals are still logged in PHP log.
- Turned off native display_errors since we're now catching all errors.
- Added reserving memory (256kb) . Can be removed safely. In case of removal we're losing only memory exhausted error when allocating last very small chunk of memory.
- Properly handled errors in __toString (exception can't be thrown in this case).
- In the YII_DEBUG===false mode it's bad to display exception name even in page title.
- In the YII_DEBUG===true mode it's still useful to get user-friendly message additionally to exception name.

framework/base/Application.php

@@ -96,6 +96,12 @@ class Application extends Module
 	private $_ended = false;
 	private $_language;
 
+	/**
+	 * @var string Used to reserve memory for fatal error handler. This memory
+	 * reserve can be removed if it's OK to write to PHP log only in this particular case.
+	 */
+	private $_memoryReserve;
+
 	/**
 	 * Constructor.
 	 * @param string $id the ID of this application. The ID should uniquely identify the application from others.
@@ -110,6 +116,7 @@ class Application extends Module
 		$this->setBasePath($basePath);
 
 		if (YII_ENABLE_ERROR_HANDLER) {
+			ini_set('display_errors', 0);
 			set_exception_handler(array($this, 'handleException'));
 			set_error_handler(array($this, 'handleError'), error_reporting());
 		}
@@ -126,7 +133,6 @@ class Application extends Module
 	 */
 	public function init()
 	{
-		ob_start();
 		$this->preloadComponents();
 	}
 
@@ -139,11 +145,42 @@ class Application extends Module
 	 */
 	public function end($status = 0, $exit = true)
 	{
-		$lastError = error_get_last();
+		if (!$this->_ended) {
+			$this->_ended = true;
+			$this->afterRequest();
+		}
+
+		if(YII_ENABLE_ERROR_HANDLER) {
+			$error = error_get_last();
+
+			if(isset($error['type']) && in_array($error['type'], ErrorException::getFatalCodes())) {
+				unset($this->_memoryReserve);
+				$exception = new ErrorException($error['message'], $error['type'], $error['type'], $error['file'], $error['line']);
+
+				if(function_exists('xdebug_get_function_stack')) {
+					$trace = array_slice(array_reverse(xdebug_get_function_stack()), 4, -1);
+					foreach($trace as &$frame) {
+						if(!isset($frame['function'])) {
+							$frame['function'] = 'unknown';
+						}
+
+						// XDebug < 2.1.1: http://bugs.xdebug.org/view.php?id=695
+						if(!isset($frame['type'])) {
+							$frame['type'] = '::';
+						}
+
+						// XDebug has a different key name
+						$frame['args'] = array();
+						if(isset($frame['params']) && !isset($frame['args'])) {
+							$frame['args'] = $frame['params'];
+						}
+					}
+
+					$ref = new \ReflectionProperty('Exception', 'trace');
+					$ref->setAccessible(true);
+					$ref->setValue($exception, $trace);
+				}
 
-		if(isset($lastError['type']) && in_array($lastError['type'], array(E_ERROR, E_PARSE))) {
-			ob_end_clean();
-			$exception = new \ErrorException($lastError['message'], 0, $lastError['type'], $lastError['file'], $lastError['line']);
 				$this->logException($exception);
 
 				if (($handler = $this->getErrorHandler()) !== null) {
@@ -152,14 +189,10 @@ class Application extends Module
 					$this->renderException($exception);
 				}
 
-			die(1);
+				$status = 1;
+			}
 		}
 
-		if (!$this->_ended) {
-			$this->_ended = true;
-			$this->afterRequest();
-		}
-		ob_end_flush();
 		if ($exit) {
 			exit($status);
 		}
@@ -173,6 +206,9 @@ class Application extends Module
 	public function run()
 	{
 		$this->beforeRequest();
+		// Allocating twice more than required to display memory exhausted error
+		// in case of trying to allocate last 1 byte while all memory is taken.
+		$this->_memoryReserve = str_repeat('x', 1024*256);
 		register_shutdown_function(array($this,'end'),0,false);
 		$status = $this->processRequest();
 		$this->afterRequest();
@@ -394,12 +430,24 @@ class Application extends Module
 	 * @param string $message the error message
 	 * @param string $file the filename that the error was raised in
 	 * @param integer $line the line number the error was raised at
-	 * @throws \ErrorException the error exception
+	 *
+	 * @throws ErrorException
 	 */
 	public function handleError($code, $message, $file, $line)
 	{
 		if (error_reporting() !== 0) {
-			throw new \ErrorException($message, 0, $code, $file, $line);
+			$exception = new ErrorException($message, $code, $code, $file, $line);
+
+			// in case error appeared in __toString method we can't throw any exception
+			$trace = debug_backtrace(false);
+			array_shift($trace);
+			foreach($trace as $frame) {
+				if($frame['function'] == '__toString') {
+					$this->handleException($exception);
+				}
+			}
+
+			throw $exception;
 		}
 	}
 

framework/base/ErrorException.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * ErrorException class file.
+ *
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\base;
+
+/**
+ * ErrorException represents a PHP error.
+ *
+ * @author Alexander Makarov <sam@rmcreative.ru>
+ * @since 2.0
+ */
+class ErrorException extends \ErrorException
+{
+	public static function getFatalCodes()
+	{
+		return array(E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR, E_COMPILE_WARNING);
+	}
+
+	/**
+	 * @return string the user-friendly name of this exception
+	 */
+	public function getName()
+	{
+		$names = array(
+			E_ERROR => \Yii::t('yii|Fatal Error'),
+			E_PARSE => \Yii::t('yii|Parse Error'),
+			E_CORE_ERROR => \Yii::t('yii|Core Error'),
+			E_COMPILE_ERROR => \Yii::t('yii|Compile Error'),
+			E_USER_ERROR => \Yii::t('yii|User Error'),
+			E_WARNING => \Yii::t('yii|Warning'),
+			E_CORE_WARNING => \Yii::t('yii|Core Warning'),
+			E_COMPILE_WARNING => \Yii::t('yii|Compile Warning'),
+			E_USER_WARNING => \Yii::t('yii|User Warning'),
+			E_STRICT => \Yii::t('yii|Strict'),
+			E_NOTICE => \Yii::t('yii|Notice'),
+			E_RECOVERABLE_ERROR => \Yii::t('yii|Recoverable Error'),
+			E_DEPRECATED => \Yii::t('yii|Deprecated'),
+		);
+		return isset($names[$this->getCode()]) ? $names[$this->getCode()] : \Yii::t('yii|Error');
+	}
+}

framework/base/Exception.php

@@ -25,4 +25,3 @@ class Exception extends \Exception
 		return \Yii::t('yii|Exception');
 	}
 }
-

framework/views/error.php

@@ -4,12 +4,13 @@
  * @var \yii\base\ErrorHandler $owner
  */
 $owner = $this->owner;
+$title = $owner->htmlEncode($exception instanceof \yii\base\Exception || $exception instanceof \yii\base\ErrorException ? $exception->getName() : get_class($exception));
 ?>
 <!DOCTYPE html>
 <html>
 <head>
 	<meta charset="utf-8" />
-	<title><?php echo get_class($exception)?></title>
+	<title><?php echo $title?></title>
 
 	<style>
 	body {
@@ -50,8 +51,8 @@ $owner = $this->owner;
 </head>
 
 <body>
-	<h1><?php echo $owner->htmlEncode($exception instanceof \yii\base\Exception ? $exception->getName() : get_class($exception)); ?></h1>
-	<h2><?php echo nl2br($owner->htmlEncode($exception->getMessage()))?>	</h2>
+	<h1><?php echo $title?></h1>
+	<h2><?php echo nl2br($owner->htmlEncode($exception->getMessage()))?></h2>
 	<p>
 		The above error occurred while the Web server was processing your request.
 	</p>

framework/views/exception.php

@@ -4,12 +4,13 @@
  * @var \yii\base\ErrorHandler $owner
  */
 $owner = $this->owner;
+$title = $owner->htmlEncode($exception instanceof \yii\base\Exception || $exception instanceof \yii\base\ErrorException ? $exception->getName().' ('.get_class($exception).')' : get_class($exception));
 ?>
 <!DOCTYPE html>
 <html>
 <head>
 	<meta charset="utf-8" />
-	<title><?php echo get_class($exception)?></title>
+	<title><?php echo $title?></title>
 	<style>
 	html,body,div,span,applet,object,iframe,h1,h2,h3,h4,h5,h6,p,blockquote,pre,a,abbr,acronym,address,big,cite,code,del,dfn,em,font,img,ins,kbd,q,s,samp,small,strike,strong,sub,sup,tt,var,b,u,i,center,dl,dt,dd,ol,ul,li,fieldset,form,label,legend,table,caption,tbody,tfoot,thead,tr,th,td{border:0;outline:0;font-size:100%;vertical-align:baseline;background:transparent;margin:0;padding:0;}
 	body{line-height:1;}
@@ -160,7 +161,7 @@ $owner = $this->owner;
 
 <body>
 <div class="container">
-	<h1><?php echo get_class($exception)?></h1>
+	<h1><?php echo $title?></h1>
 
 	<p class="message">
 		<?php echo nl2br($owner->htmlEncode($exception->getMessage()))?>