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

This reverts commit e60889ac4d85e6ec1083ab95dc84b2b3c0a95dd6.

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;

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
      */