Unhandled Rejection

[yamila-fraiman]

Suddenly my server stop working and throws the following error. For the moment, I resolved it by dropping the ojlinttaskcollections db.

You have triggered an unhandledRejection, you may have forgotten to catch a Promise rejection:
TypeError: Cannot read property '_id' of undefined
    at rollbackSave (/home/inamu/webserver/node_modules/fawn/lib/roller.js:137:30)
    at /home/inamu/webserver/node_modules/fawn/lib/roller.js:98:39
    at tryCatcher (/home/inamu/webserver/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/home/inamu/webserver/node_modules/bluebird/js/release/promise.js:512:31)
    at Promise._settlePromise (/home/inamu/webserver/node_modules/bluebird/js/release/promise.js:569:18)
    at Promise._settlePromiseCtx (/home/inamu/webserver/node_modules/bluebird/js/release/promise.js:606:10)
    at Async._drainQueue (/home/inamu/webserver/node_modules/bluebird/js/release/async.js:138:12)
    at Async._drainQueues (/home/inamu/webserver/node_modules/bluebird/js/release/async.js:143:10)
    at Immediate.Async.drainQueues (/home/inamu/webserver/node_modules/bluebird/js/release/async.js:17:14)
    at runCallback (timers.js:574:20)
    at tryOnImmediate (timers.js:554:5)
    at processImmediate [as _immediateCallback] (timers.js:533:5)

[e-oj]

What version of Fawn? and can you share the code that causes that error?

[yamila-fraiman]

2.1.5
I found the error was because I forgot to call next on pre save in the second transaction. But I think that lib should catch exceptions to prevent breaking the server if there is an error.

`
let transaction = Fawn.Task();

		transaction.save('User', {
			email: req.body.user.email
		});

		let data = lodash.pick(req.body, fields);
		data.user = {$ojFuture: '0._id'};
		transaction.save('Organization', data);`

[e-oj]

The error bubbles up to the user when something goes wrong that the user needs to know about. You can always catch any errors that occur to prevent crashing.

let task = Fawn.Task();

task.save(...);
task.update(...);

try{
  let result = await task.run();
}
catch(err){
  console.log(err.message);
}

[yamila-fraiman]

I use the following code but wasn't enough

transaction.run({useMongoose: true}) .then((results) => {}) .catch((err) => {})

[e-oj]

That's strange. I'll look into it.