Unable to catch thrown errors from try/catch block, around a function that uses promising.

[silverbucket]

Hey man, I'm still having a hell of a time figuring out how to catch thrown errors from within platforms in the listener.

First off, I created a test case within sockethub, if you want to see the failure im talking about. If you update your sockethub repo to the latest, you'll find a test case for this:
https://github.com/sockethub/sockethub/blob/master/test/70-fullstack-suite.js#L285

I have a test platform which throws an error from within a promise then:
https://github.com/sockethub/sockethub/blob/master/lib/platforms/test.js#L17

    fetch: function () {
      var promise = session.promising();
      return testFunc().then(function () {
        throw new Error('TEST PLATFORM THROWING ERROR');
        promise.fulfill();
      });
      return promise;
    },

Then, when the listener calls the platforms function, it wraps the call in a try block:
https://github.com/sockethub/sockethub/blob/master/lib/sockethub/listener.js#L262

        console.info(did + 'sending job to platform handler');
        try {
          handler(job).then(function (obj) {
            _jobSuccess(jobResp, obj);
          }, function (err, obj) {
            _jobFailure(jobResp, err, obj);
          });
        } catch (e) {
          console.error(did + 'problem from platform ' + e.toString());
          jobResp(""+e.toString(), false);
          setTimeout(function () {
            throw new Error(did + 'RESET PLATFORM on call to [' + job.verb +
                            ']: ' + e.toString());
          }, 0);
        }

In the above case I'm return the promise, even though I do more stuff to handle the success. It seems ilogical that I should be returning the promise from another func, when I do things based on the success, and then i have to manufature my own promise to fulfill manually and send back.

If I return the result of testFunc - then the thrown error shows up as a failed promise.

If I don't return the result of testFunc - then the error is caught within promising.

Either way, there's no way for me know catch thrown errors. I need to know if an error is thrown. If an error is thrown, I reset the process completely. If a promise is failed, I don't do anything. The use control flow is completely different.

Also, I can't rely on platform devs to return all their promises. If an error is thrown, no matter what, I need to catch that and handle it.

How can I get this result?

[silverbucket]

Some relevant discussion a few years back:
kriskowal/q#30

From what I understand, if they used an end(); on the "mother" caller of a promise chain, then wrapping that in a try/catch will catch thrown exceptions?

I don't understand why it's OK to consider a thrown exception or a rejected promise as the same. A thrown error could be any weird corruption during execution, whereas a rejected promise generally would imply things are still working, that operation just didn't work. So, a thrown exception could be syntax errors, or some serious bugs in code - those need to be hadled differently than simply a promise saying "we couldn't save a file" or something.