From 8350f52b9d25ddfa6489faddc02433031c2682ea Mon Sep 17 00:00:00 2001
From: Avital Oliver <avital@thewe.net>
Date: Wed, 10 Apr 2013 21:13:55 -0700
Subject: [PATCH] Improve Meteor.Error

- Capture stack traces on server (Meteor.Error objects are only created on the client, not thrown)
- Set a message
- Improve inheritence pattern

Before: (note that the stack trace shows the line in which Meteor.Error is defined, not where it got thrown)
===
- exception - message
Error
    at app/packages/livedata/livedata_common.js:143:26
    at /private/var/folders/tp/sc9b5w7n2qndz3chpmktwy_w0000gn/T/meteor-test-runikymph/.meteor/local/build/server/server.js:282:7
    at Array.forEach (native)
    at Function._.each._.forEach (/Users/avital/meteor/dev_bundle/lib/node_modules/underscore/underscore.js:79:11)
    at run (/private/var/folders/tp/sc9b5w7n2qndz3chpmktwy_w0000gn/T/meteor-test-runikymph/.meteor/local/build/server/server.js:227:7)

After:
===
- exception - message User validation failed [403]
Error: User validation failed [403]
    at app/packages/accounts-base/accounts_server.js:164:13
    at Array.forEach (native)
    at Function._.each._.forEach (app/packages/underscore/underscore.js:79:11)
    at Object.Accounts.insertUserDoc (app/packages/accounts-base/accounts_server.js:162:5)
    at Object.Accounts.updateOrCreateUserFromExternalService (app/packages/accounts-base/accounts_server.js:264:21)
    at null.func (app/packages/accounts-base/accounts_tests.js:18:28)
    at app/packages/tinytest/tinytest.js:299:16
    at app/packages/meteor/timers.js:54:36
    at _.extend.withValue (app/packages/meteor/dynamics_nodejs.js:31:17)
    at f (app/packages/meteor/timers.js:12:51)
---
 packages/livedata/livedata_common.js | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/packages/livedata/livedata_common.js b/packages/livedata/livedata_common.js
index c9af4b81dc..a919cd8cae 100644
--- a/packages/livedata/livedata_common.js
+++ b/packages/livedata/livedata_common.js
@@ -122,6 +122,16 @@ Meteor._CurrentInvocation = new Meteor.EnvironmentVariable;
 Meteor.Error = function (error, reason, details) {
   var self = this;
 
+  // Meteor.Error is defined on both client and server, but it only
+  // has a stack trace on the server. Luckily, Error.captureStackTrace
+  // achieves this on V8. Googling and experimentation found no way to
+  // capture stack traces on all browsers, so it seems that this is
+  // not a viable general pattern for creating custom Error
+  // classes. If we need to do that, we'd probably be best off setting
+  // a 'type' property on the Error object instead.
+  if (Error.captureStackTrace)
+    Error.captureStackTrace(self, Meteor.Error);
+
   // Currently, a numeric code, likely similar to a HTTP code (eg,
   // 404, 500). That is likely to change though.
   self.error = error;
@@ -138,6 +148,21 @@ Meteor.Error = function (error, reason, details) {
   // never expect this to be shown to end users, only developers, so
   // it doesn't need to be pretty.)
   self.details = details;
+
+  // This is what gets displayed at the top of a stack trace. Current
+  // format is "[404]" (if no reason is set) or "File not found [404]"
+  if (self.reason)
+    self.message = self.reason + ' [' + self.error + ']';
+  else
+    self.message = '[' + self.error + ']';
 };
 
-Meteor.Error.prototype = new Error;
+// http://davidshariff.com/blog/javascript-inheritance-patterns/
+var inherits = function (child, parent) {
+  var tmp = function () {};
+  tmp.prototype = parent.prototype;
+  child.prototype = new tmp;
+  child.prototype.constructor = child;
+};
+
+inherits(Meteor.Error, Error);
\ No newline at end of file