Support phpdbg SAPI in Debug::enable()

Debug.php

@@ -45,7 +45,7 @@ class Debug
             error_reporting(-1);
         }
 
-        if ('cli' !== PHP_SAPI) {
+        if (!in_array(PHP_SAPI, array('cli', 'phpdbg'))) {
             ini_set('display_errors', 0);
             ExceptionHandler::register();
         } elseif ($displayErrors && (!ini_get('log_errors') || ini_get('error_log'))) {

ErrorHandler.php

@@ -149,9 +149,20 @@ class ErrorHandler
         }
         if (!$replace && $prev) {
             restore_error_handler();
+            $handlerIsRegistered = is_array($prev) && $handler === $prev[0];
+        } else {
+            $handlerIsRegistered = true;
         }
-        if (is_array($prev = set_exception_handler(array($handler, 'handleException'))) && $prev[0] === $handler) {
+        if (is_array($prev = set_exception_handler(array($handler, 'handleException'))) && $prev[0] instanceof self) {
             restore_exception_handler();
+            if (!$handlerIsRegistered) {
+                $handler = $prev[0];
+            } elseif ($handler !== $prev[0] && $replace) {
+                set_exception_handler(array($handler, 'handleException'));
+                $p = $prev[0]->setExceptionHandler(null);
+                $handler->setExceptionHandler($p);
+                $prev[0]->setExceptionHandler($p);
+            }
         } else {
             $handler->setExceptionHandler($prev);
         }
@@ -533,15 +544,16 @@ class ErrorHandler
                 }
             }
         }
+        $exceptionHandler = $this->exceptionHandler;
+        $this->exceptionHandler = null;
         try {
-            if (null !== $this->exceptionHandler) {
-                return \call_user_func($this->exceptionHandler, $exception);
+            if (null !== $exceptionHandler) {
+                return \call_user_func($exceptionHandler, $exception);
             }
             $handlerException = $handlerException ?: $exception;
         } catch (\Exception $handlerException) {
         } catch (\Throwable $handlerException) {
         }
-        $this->exceptionHandler = null;
         if ($exception === $handlerException) {
             self::$reservedMemory = null; // Disable the fatal error handler
             throw $exception; // Give back $exception to the native handler

Exception/FatalThrowableError.php

@@ -36,7 +36,8 @@ class FatalThrowableError extends FatalErrorException
             $e->getCode(),
             $severity,
             $e->getFile(),
-            $e->getLine()
+            $e->getLine(),
+            $e->getPrevious()
         );
 
         $this->setTrace($e->getTrace());

Tests/ErrorHandlerTest.php

@@ -34,7 +34,7 @@ class ErrorHandlerTest extends TestCase
 
             $newHandler = new ErrorHandler();
 
-            $this->assertSame($newHandler, ErrorHandler::register($newHandler, false));
+            $this->assertSame($handler, ErrorHandler::register($newHandler, false));
             $h = set_error_handler('var_dump');
             restore_error_handler();
             $this->assertSame(array($handler, 'handleError'), $h);
@@ -530,4 +530,18 @@ class ErrorHandlerTest extends TestCase
             throw $e;
         }
     }
+
+    /**
+     * @expectedException \Exception
+     * @group no-hhvm
+     */
+    public function testCustomExceptionHandler()
+    {
+        $handler = new ErrorHandler();
+        $handler->setExceptionHandler(function ($e) use ($handler) {
+            $handler->handleException($e);
+        });
+
+        $handler->handleException(new \Exception());
+    }
 }

Tests/Exception/FlattenExceptionTest.php

@@ -105,7 +105,7 @@ class FlattenExceptionTest extends TestCase
     /**
      * @dataProvider flattenDataProvider
      */
-    public function testFlattenHttpException(\Exception $exception, $statusCode)
+    public function testFlattenHttpException(\Exception $exception)
     {
         $flattened = FlattenException::create($exception);
         $flattened2 = FlattenException::create($exception);
@@ -120,7 +120,7 @@ class FlattenExceptionTest extends TestCase
     /**
      * @dataProvider flattenDataProvider
      */
-    public function testPrevious(\Exception $exception, $statusCode)
+    public function testPrevious(\Exception $exception)
     {
         $flattened = FlattenException::create($exception);
         $flattened2 = FlattenException::create($exception);
@@ -167,7 +167,7 @@ class FlattenExceptionTest extends TestCase
     /**
      * @dataProvider flattenDataProvider
      */
-    public function testToArray(\Exception $exception, $statusCode)
+    public function testToArray(\Exception $exception)
     {
         $flattened = FlattenException::create($exception);
         $flattened->setTrace(array(), 'foo.php', 123);
@@ -187,7 +187,7 @@ class FlattenExceptionTest extends TestCase
     public function flattenDataProvider()
     {
         return array(
-            array(new \Exception('test', 123), 500),
+            array(new \Exception('test', 123)),
         );
     }