New warnings in 3.0

All my jasmine tests started producing over thousand warnings, after upgrading from 2.x to 3.x

• Warning: a promise was rejected with a non-error: [object Array]
• Warning: a promise was created in a handler but none were returned from it

And this is all for a library that passes tests without warnings against every promise library there is out there, including Bluebird 2.x

I went through the code referred to by the warnings, and none of them make sense to me, i.e. they look completely wrong.

[benjamingr]

@vitaly-t bluebird is an opinionated promise library, our philosophy is to make things that work for 99% of people 100% of the time. If you don’t like the opinion of the library that’s fine - you’re more than welcome to fork it it’s an open source project.

Rejecting with non-errors is an obvious bug, an array is not an error - it doesn’t have a stack trace and it’ll make your life hell to throw arrays (or reject with them) in large production code bases.

Creating promises in then but not handling them is an obvious bug as well - most likely a deferred anti-pattern which leaves room for a lot of errors.

[vitaly-t]

Wow, those two are shocking changes…

• Warning: a promise was rejected with a non-error: [object Array]

That’s trying to create your own standard against what JavaScript supports, like throw;, which is a perfectly valid command, and is not meant to produce any warning, and the same is expected from any promise library.

• Warning: a promise was created in a handler but none were returned from it

In my code and in other people’s it is all over the place when undefined is used as a perfectly good value to either return or resolve with. Your warning here is breaking a perfectly good code pattern, and nobody is gonna like that.

In all, I think you will be crucified for these two warnings, unless you turn around quickly and make them optional, that which I strongly suggest.