Runaway promise warning lacks long stack trace when using chained fromCallback() calls

[ben-page]

I found a case where the runaway promise warning does not include the long stack trace.

var Promise = require('bluebird');
Promise.config({warnings: true, longStackTraces: true});

function fn(cb) {
    setTimeout(cb.bind(null, null, 'result'), 0);
}

Promise.fromCallback(function (callback) {
    fn(callback);
})
.then(function (t) {
    Promise.fromCallback(function (callback) { //runaway promise
        fn(callback);
    });
});

Warning: a promise was created in a handler but was not returned from it
    at Timer.listOnTimeout (timers.js:92:15)

[ben-page]

I'm on 3.1.1

[petkaantonov]

Duplicate of #9

[ben-page]

@petkaantonov I don't think this duplicate of the issue #9. That issue seems to be about an error thrown inside asynchronous (setTimeout) code executed inside a Promise.

My issue is about the runaway Promise warning not including a long stack trace. When the runaway Promise originates from fromCallback(). If it originated from a different method, it would work. I think this may be related to #871. And I do not believe this would require domains, AsyncListener, or similar to solve.

[ben-page]

To illustrate my point, here I made a custom implementation of fromCallback() based on the Promise constructor. It creates a long stack trace as expected.

Promise.config({warnings: true, longStackTraces: true});

function fn(cb) {
    setTimeout(cb.bind(null, null, 'result'), 0);
}

function fromCallback(nodeFunction) {
    return new Promise(function(resolve, reject) {
        nodeFunction(function (err, res) {
            if (err)
                return reject(err);

            resolve(res);
        });
    });
}

fromCallback(fn)
    .then(function (t) {
        fromCallback(fn);
    });