V8 - 4.9.279.0

[bricss]

Hi there,

Chrome 49 landed into Dev channel at this week with V8 4.9.279.0 on-board and its time to think about when to drop it into the master branch 😎

P. S.: V8 4.9.279.0 - covers 91% of ES6 spec. 🔥

[bnoordhuis]

We normally upgrade after the release branch is created in the V8 repository (e.g. the 4.8 branch) but there isn't one yet for 4.9.

[ofrobots]

If you want to play with Node.js with V8 4.9, I have a branch here: https://github.com/ofrobots/node/tree/vee-eight-4.9

It is not ready for prime time yet. Specifically there is a change in V8 DEPS and we need now have a source dependency (chromium/src/base/trace_event/common.git) to be able to build. I am working on figuring out how to best deal with that in Node.

[nicolasparada]

Can use es2015 modules syntax (import/export) with the V8 4.9?

[MylesBorins]

@nicolasparada it does not appear that module loading has been implemented in v8 yet. You can follow progress on the v8 bugtracker and whatwg/loader

[nicolasparada]

Ok.

[YurySolovyov]

@thealphanerd I think the first link should be https://bugs.chromium.org/p/v8/issues/detail?id=1569

[cjihrig]

I'm going to close this. We update V8 fairly regularly already. 4.9 will make its way in eventually, and this issue will likely be forgotten about by then.

[josephschmitt]

The V8 version has been stuck at 4.6.85.31 since November. Is it still planned to pull in the latest V8 regularly? 4.9 has a bunch of new ES6 support I'd love to be able to use.

[r-52]

@josephschmitt are you referring to a specific version? The master branch has a v8 version 4.9 and there's a wip pr to update v8 to the version 5 release.

[josephschmitt]

@romankl I looked up the current version of V8 from here https://nodejs.org/en/download/releases/ and it states that Node.js v5.9.0 has V8 v4.6.85.31. Is there something I'm missing?

[bricss]

I suppose Node.js v6.0.0 will include V8 v4.9~

[jbergstroem]

@bricss actually, we're looking to use 5.0 for node 6: #5766

[josephschmitt]

@jbergstroem so is node 6 the next time the v8 version will be bumped up?

[rvagg]

@josephschmitt for io.js v1 to Node v5 we have pinned the semver-major version to the major version of V8 because changes in the V8 C++ ABI are breaking between (most) major versions which leads to compiled addons not being usable without recompiling which is something we've not been willing to accept during the life of a semver-major—you should not have to recompile a native addon when using a particular semver-major of Node (and semver-minor prior to v1).

However, we have come to a rough agreement that we would be a little bit more flexible from v6 onward, or at least try to be. The priority of keeping the ABI stable over the life of a semver-major is still paramount but we do have some flexibility in how we manage V8 to achieve that. It's not always the case that version bumps in V8 are breaking, so where they are not ABI-breaking we could upgrade and where they are ABI-breaking we could get creative with how we deal with that, perhaps even patching V8 when we land it to undo the breaks, depending on how dramatic they are.

The caveat here is that we still want LTS to be super-stable so we'll have to stop any V8 upgrading prior to a semver-major shifting to LTS (which happens in October, so perhaps a couple of months prior to that) in order for things to settle down before we move a release line into something we're willing to call as stable as an LTS line should be.

I believe we might also be getting a tiny bit more assistance from the V8 team on this front too as they are using Node much more internally at Google now and the lack of embrace of new versions is as much of a concern for them as it is for many of the rest of us.

[JavaScriptDude]

This is sweet! Having optional function parameters and array based restructuring will be great to play with! Looking forward to the first RC.