deprecate domains

[jonathanong]

what's the status on domains? can we deprecate it before v1?

[juliangruber]

afaik no breaking changes will happen until v1

[jonathanong]

just labeling something as deprecated is not a breaking change

[juliangruber]

gotcha, 👍 from me, domains have only meant pain to me personally

[rvagg]

I'm on board, I bet a bunch of TC members would be too, marking as tc-agenda

[indutny]

+1

[Marak]

I never understood why domains were added to core.

It seemed wrong at the time, and still seems equally as wrong.

For backwards compatibility, will it be possible to put this functionality into an npm module as a custom add-on? Does this already exist?

[Fishrock123]

+1 domains are confusing and I hear nothing but incompatibilities and edge cases

[othiym23]

+1 sad 🎺

@Marak

I never understood why domains were added to core.

There's a place for unified sync & async error handling for Node, and due to the way that state propagates through core, there at least need to be hooks exposed by core to facilitate this. uncaughtException is too gross-grained, not everybody uses (or likes) promises, try/catch + stream error listeners + callback convention is complicated to teach and learn and harder to master, etc. Probably the best effort at this so far is @piscisaureus and co's zones, but that solution has limitations that are going to be tough to resolve outside core.

I'm hopeful that @trevnorris's AsyncWrap can provide the foundation for a better / lower-impact way of building something useful along these lines in the future, and I consider domains a very useful failure that helped point to what AsyncWrap / AsyncListener should do.

[bnoordhuis]

It would have to go through the TC but I don't think there is much opposition to deprecating domains. Who volunteers to follow up with a pull request?

[tellnes]

@bnoordhuis A deprecation warning if you call domain.create()? Or when you require it since it has side effects (acording to code comments).

[bnoordhuis]

@tellnes I'll leave that to your own judgment. Doing it at require() time would get the message out most effectively but it might end up being extremely annoying.

If you do do it at require() time, you should also update lib/repl.js and make it load the domain module lazily.

[tellnes]

lib/repl.js needs to be changed anyway because it is calling domain.create().

[rlidwka]

Is there a suitable replacement that could be used? Repl is a valid use-case for example.