New warnings should indicate origin

[floross]

The new warnings introduces by bluebird 3 are quite handy to avoid bugs, but the error they refer to can be quite hard to pinpoint in large codebases:

Warning: a promise was created in a  handler but was not returned from it
at processImmediate [as _immediateCallback] (timers.js:367:17)

In my case this was due to the use of old-style callbacks that didn't return anything, but maybe Bluebird could somewhat use the longStackTrace mechanism to indicate the origin of the error to facilitate debugging.

[petkaantonov]

There should be a long stack trace as this warning is not even enabled if long stack traces are not enabled

[floross]

Long stack traces are enable but I go the error above anyway.

My bluebird configuration:

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

[floross]

This code can reproduce the error:

var Promise = require('bluebird');

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

Promise.resolve()
    .then(function () {
        Promise.resolve();
    })
;

This warning show up:

Warning: a promise was created in a  handler but was not returned from it
    at processImmediate [as _immediateCallback] (timers.js:367:17)

Ps: I'am currently using the 3.0.5 version of bluebird

[petkaantonov]

Thanks, I'll look into it

[petkaantonov]

This was actually bug with Promise.resolve rather than the warning system