1.2.0: .nodeify doesn't return a promise

[oleksiyk]

Hi!

I noticed .nodefiy doesn't return a promise back in 1.2.0:

var Promise = require('bluebird')

var cb = function () {}
var p = Promise.delay(500).nodeify(cb)

console.log(p) // --> undefined

[petkaantonov]

This is to prevent people from using callbacks and promises at the same time

[oleksiyk]

Isn't it what documentation says here: https://github.com/petkaantonov/bluebird/blob/master/API.md#nodeifyfunction-callback---promise

Returns back this promise instead of creating a new one.

It is also a breaking change for projects that were exporting both interfaces. How is it possible that such breaking change is made without any acknowledgements in minor version upgrade?

[oleksiyk]

I see that it returns undefined only in the presence of callback, but it still breaks hundreds of tests people may had in their projects: checking for both valid promise and called callback. Now each test should be duplicated. You had only 1 'unintuitive' issue report now you have broken dependant projects.

[benjamingr]

@oleksiyk #151

In a line - it didn't work too well before.

In my opinion - a dual interface is a mistake and opens up all sorts of problems, especially given how simple (and fast!) it is to promisify a node interface, or nodeify a promise based one. You can always support a promise interface and tell users who want callbacks to .nodeify at the end of their chain or support a callback interface and tell users to consider Bluebird and .promisifyAll

That said, I fully see why this change upsets you, we try to make as few such breaking changes as possible but sometimes we realize an API mistake was made. Sorry.

[petkaantonov]

I think we can quickly fix this in a patch.. 2.0 will come soon anyway

[oleksiyk]

Yeah, sorry I was too much upset. I agree that this is correct behaviour. That's just that I need to fix about 1000 tests in my projects.

[petkaantonov]

Yes I did not realize anyone was actually relying on this behavior - I take backwards compatibility very seriously so I will fix this asap in a patch.

[oleksiyk]

I actually think that both interfaces can only be used in such limited cases as tests (just to save typing and copy/pasting). So - you decide.

[jmdobry]

@petkaantonov
A library of mine (using Bluebird of course) exposes the dual callback-promise interface. What does this issue mean for my library's continued use of Bluebird?

[petkaantonov]

It makes no sense to use both interfaces simultaneously so probably nothing

[jmdobry]

So, I can still export both interfaces, but only one can be used, right?
On Apr 12, 2014 2:34 AM, "Petka Antonov" notifications@github.com wrote:

It makes no sense to use both interfaces simultaneously so probably nothing

Reply to this email directly or view it on GitHubhttps://github.com//issues/168#issuecomment-40275174
.