Log Server Errors

[campersau]

Some recent bugreports (#689, #679) contain client- and serverside logs but they do not contain any useful errors.

The main reasons for this are:

1. JavaScript Errors are not serializable with JSON.stringify by default
2. The jsonResultOrFailProm does not log anything in case of an error

---

The first commit fixes point 1 by implementing toJSON on Error.
Before an empty object {} would be returned now the response includes all fields of an Error object such as message and stack:

{"stack":"Error: Test\n    at exports.parseGitSubmodule (P:\\ungit\\source\\git-parser.js:217:19)\n    at tryCatcher (P:\\ungit\\node_modules\\bluebird\\js\\release\\util.js:11:23)\n    at Promise._settlePromiseFromHandler (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:491:31)\n    at Promise._settlePromise (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:548:18)\n    at Promise._settlePromise0 (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:593:10)\n    at Promise._settlePromises (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:676:18)\n    at Promise._fulfill (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:617:18)\n    at Promise._settlePromise (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:561:21)\n    at Promise._settlePromise0 (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:593:10)\n    at Promise._settlePromises (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:676:18)\n    at Promise._fulfill (P:\\ungit\\node_modules\\bluebird\\js\\release\\promise.js:617:18)\n    at P:\\ungit\\node_modules\\bluebird\\js\\release\\nodeback.js:42:21\n    at fs.js:334:14\n    at P:\\ungit\\node_modules\\npm-registry-client\\node_modules\\graceful-fs\\graceful-fs.js:42:10\n    at FSReqWrap.oncomplete (fs.js:95:15)","message":"Test"}

So the errors are visible in the network panel:

---

The second commit logs the information provided by commit 1 in the client console.

---

The third commit logs errors in the server console and fixes point 2.

2016-02-05T20:12:23.945Z - info: GET /api/submodules?path=P%3A%5Cvstup&socketId=3
Unhandled error: Test
ReferenceError: Test
    at exports.parseGitSubmodule (P:\ungit\source\git-parser.js:217:19)
    at tryCatcher (P:\ungit\node_modules\bluebird\js\release\util.js:11:23)
    at Promise._settlePromiseFromHandler (P:\ungit\node_modules\bluebird\js\release\promise.js:491:31)
    at Promise._settlePromise (P:\ungit\node_modules\bluebird\js\release\promise.js:548:18)
    at Promise._settlePromise0 (P:\ungit\node_modules\bluebird\js\release\promise.js:593:10)
    at Promise._settlePromises (P:\ungit\node_modules\bluebird\js\release\promise.js:676:18)
    at Promise._fulfill (P:\ungit\node_modules\bluebird\js\release\promise.js:617:18)
    at Promise._settlePromise (P:\ungit\node_modules\bluebird\js\release\promise.js:561:21)
    at Promise._settlePromise0 (P:\ungit\node_modules\bluebird\js\release\promise.js:593:10)
    at Promise._settlePromises (P:\ungit\node_modules\bluebird\js\release\promise.js:676:18)
    at Promise._fulfill (P:\ungit\node_modules\bluebird\js\release\promise.js:617:18)
    at P:\ungit\node_modules\bluebird\js\release\nodeback.js:42:21
    at fs.js:334:14
    at P:\ungit\node_modules\npm-registry-client\node_modules\graceful-fs\graceful-fs.js:42:10
    at FSReqWrap.oncomplete (fs.js:95:15)

[campersau]

This also exposes a lot of Unhandled errors in the tests see https://travis-ci.org/FredrikNoren/ungit/jobs/107326833
But tests are passing anyway.

[jung-kim]

👍 * 💯

This will most definitely help us with debugging! While we are being clever, can we be more clever by doing below as well? with below code we can reduce https://github.com/campersau/ungit/blob/server_errors/source/git-api.js#L114-L120 to console.error(err); right?

Object.defineProperty(Error.prototype, 'toString', {
  value: function() {
    return 'Message: ' + this.message + '\n' + this.stack;
  }
});

[campersau]

@codingtwinky No, this somehow does not work. Maybe some Errors are overriding the default toString implementation.

For example the TypeError you see here would only be traced like this:

    V quickstatus should say inited in inited directory (41ms)
[TypeError: Cannot read property 'indexOf' of undefined]
    V commit should fail on when there's no files to commit

[campersau]

Sorry, it would have worked if the code was in a file which would be loaded everywhere. Looks like the tests mentioned do not require source/server.js to be loaded.

Should I move the Object.defineProperty code to git-promise.js and add your toString override?

[jung-kim]

Hmmm... I'm wondering if including in .../source/config.js as it would get used via both front and back.

Would that be a better place? if not, I think git-promise is a good place.

[campersau]

I moved the code to config.js and also added your toString override.

[FredrikNoren]

👍 this is awesome!

[campersau]

What happend here?

• https://travis-ci.org/FredrikNoren/ungit/jobs/107821676#L990
• https://travis-ci.org/FredrikNoren/ungit/jobs/107821677#L1162

Looks like Node.js 0.10 does not like the toString override? Without that it worked: https://travis-ci.org/FredrikNoren/ungit/jobs/107326829#L995

[jung-kim]

I can reproduce this error in node/0.10.41. It seems like implementation of Error#stack is calling or referencing to Error#toString() and continuously calls each other... Which is really interesting as stack is a property.

This seems to be fixed in later version and I guess I really shouldn't mess with existing core implementations.... :P

> var n = 0;
undefined
> Object.defineProperty(Error.prototype, 'toString', {
...   value: function() {
.....     if (n++ > 5) return 'ugh oh';
.....     return this.stack;
.....   }
... });
[undefined]
> var e = new Error('abc')
ugh oh
    at REPLServer.self.eval (repl.js:110:21)
    at Interface.<anonymous> (repl.js:239:12)
    [TL;DR;]
> e.stack
ugh oh
    at repl:1:2
    at REPLServer.self.eval (repl.js:110:21)
    at Interface.<anonymous> (repl.js:239:12)
    at Interface.emit (events.js:95:17)
    at Interface._onLine (readline.js:203:10)
    at Interface._line (readline.js:532:8)
    at Interface._ttyWrite (readline.js:761:14)
    at ReadStream.onkeypress (readline.js:100:10)
    at ReadStream.emit (events.js:98:17)
    at emitKey (readline.js:1096:12)
>