From 49790775624c422f67057f7bb936f35df920e391 Mon Sep 17 00:00:00 2001
From: dead_horse <dead_horse@qq.com>
Date: Fri, 23 May 2014 21:15:03 +0800
Subject: [PATCH] assert non-error obj pass to app.onerror, fixed #287

---
 lib/application.js | 7 ++++++-
 lib/context.js     | 7 +++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/lib/application.js b/lib/application.js
index a265a0d..f5599dd 100644
--- a/lib/application.js
+++ b/lib/application.js
@@ -155,10 +155,15 @@ app.createContext = function(req, res){
  */
 
 app.onerror = function(err){
+  if (!err) return;
+  assert(err instanceof Error, 'non-error thrown: ' + err);
+
   if (404 == err.status) return;
   if ('test' == this.env) return;
+
+  var msg = err.stack || err.toString();
   console.error();
-  console.error(err.stack.replace(/^/gm, '  '));
+  console.error(msg.replace(/^/gm, '  '));
   console.error();
 };
 
diff --git a/lib/context.js b/lib/context.js
index 1e2f0b7..7b182cd 100644
--- a/lib/context.js
+++ b/lib/context.js
@@ -91,18 +91,17 @@ var proto = module.exports = {
 
     assert(err instanceof Error, 'non-error thrown: ' + err);
 
+    // delegate
+    this.app.emit('error', err, this);
+
     // nothing we can do here other
     // than delegate to the app-level
     // handler and log.
     if (this.headerSent || !this.writable) {
       err.headerSent = true;
-      this.app.emit('error', err, this);
       return;
     }
 
-    // delegate
-    this.app.emit('error', err, this);
-
     // unset all headers
     this.res._headers = {};