Revert "Revert "bug #17052 [2.7] Fixed flatten exception recursion with errors (GrahamCampbell)""

This reverts commit e60889ac4d85e6ec1083ab95dc84b2b3c0a95dd6.

DebugClassLoader.php

@@ -147,7 +147,7 @@ class DebugClassLoader
         try {
             if ($this->isFinder) {
                 if ($file = $this->classLoader[0]->findFile($class)) {
-                    require $file;
+                    require_once $file;
                 }
             } else {
                 call_user_func($this->classLoader, $class);

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;

README.md

@@ -15,6 +15,7 @@ Debug::enable();
 You can also use the tools individually:
 
 ```php
+use Symfony\Component\Debug\DebugClassLoader;
 use Symfony\Component\Debug\ErrorHandler;
 use Symfony\Component\Debug\ExceptionHandler;
 
@@ -25,11 +26,9 @@ if ('cli' !== php_sapi_name()) {
     ini_set('display_errors', 1);
 }
 ErrorHandler::register();
+DebugClassLoader::enable();
 ```
 
-Note that the `Debug::enable()` call also registers the debug class loader
-from the Symfony ClassLoader component when available.
-
 This component can optionally take advantage of the features of the HttpKernel
 and HttpFoundation components.
 

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
      */