Optional spawn sync

[johanneswuerbach]

Compiling native extensions requires a working compiler toolchain

Related: testem/testem#588

[satazor]

//cc @BigstickCarpet

[JamesMessinger]

@johanneswuerbach - I think this is actually an issue with Spawn Sync, not Cross Spawn. Perhaps send them a pull request instead?

If we make spawn-sync an optional dependency, then we have no graceful fallback for Node < 0.12. Our only option is to throw a runtime error, which is not ideal. On the other hand, if Spawn Sync makes thread-sleep an optional dependency, then it has a graceful fallback (it falls-back to a simple loop)

[JamesMessinger]

It looks like Spawn Sync is doing some strange stuff in their package.json file. They don't depend on thread-sleep directly, they depend on try-thread-sleep, which in-turn depends on thread-sleep. What's odd is that try-thread-sleep isn't listed as a dependency or optionalDependency, but rather as a devDependency. They then use a post-install script to install it as a dependency. I'm not sure why they're doing it that way.

The other weird thing is that try-thread-sleep has thread-sleep as an optional dependency, which means this whole issue should be moot, since nowhere in the entire dependency chain is thread-sleep actually a dependency of anything. So, as far as I can tell, thread-sleep (which is the native C module that's causing the whole issue) shouldn't ever actually get installed unless an app explicitly declares it as a dependency.

Or am I missing something?

[johanneswuerbach]

Maybe @ForbesLindesay knows more?

Also //cc @stefanpenner

[stefanpenner]

you are correct, it is in spawn-sync.

@johanneswuerbach the issue in testem is, one cannot use sync spawn of anykind in node < 0.12 without a native extension. So it should be confirmed testem itself doesn't rely on that.

If thats the case, it might be interesting to split node-cross-spawn into another more specific module, node-cross-spawn-async which would never require native extensions.

[johanneswuerbach]

Yep, testem is only using the async version. I'll lock to 0.2.9 until this is resolved.

[stefanpenner]

Yep, testem is only using the async version. I'll lock to 0.2.9 until this is resolved.

👍

[johanneswuerbach]

Issue created. Closing.

[ForbesLindesay]

Spawn-sync only has an optional native dependency (if that fails to build it falls back to busy waiting which is bad for performance but works fine). You will get an error message during installation, which you can safely ignore.

[stefanpenner]

but works fine)

unfortunately, there is no way to reasonable silence the failure. Users become confused and assume the install failed entirely :(