Does make sense to upgrade V8 to 5.1?

[ghaiklor]

V8 team has published new version today - http://v8project.blogspot.com/2016/04/v8-release-51.html - bringing a few performance and GC improvements.

Does it make sense to integrate 5.1 with NodeJS 6.0 or we have no time for this?

[addaleax]

@nodejs/v8

[ChALkeR]

@ghaiklor It's unstable.

It will get stable in time with Chrome 51 release, which isn't going to happen this month.

[ChALkeR]

It might be time for a vee-eight-5.1 branch, though =).

[ofrobots]

Anyone creating a vee-eight-5.1 might want to look at the (unreviewed) fixes we keep in the vee-eight-lkgr branch over at http://github.com/v8/node.

[jasnell]

Let's hold off until it goes stable.

[jasnell]

Or is it stable already?

[Fishrock123]

It is not stable.

[seeekr]

Question from the sidelines because I have not fully understood this part of the new node release strategy yet:
Once node v6 is released initially, is it going to be fair game to upgrade v8 before the next major node release (v7)? Or will node v6 be "stuck" (too harsh of a term, considering how excellently up to date node is with v8 nowadays thanks to all you guys' efforts!) on the initially chosen v8 version, 5.0, even as node v6 goes into LTS mode in October? Thanks for clarifying!

EDITing to add: With 6 months of runway into an LTS release it seems that upgrading v8 at least up to something like 3 months before a release turns LTS could be a sensible thing to do?
Though the idea with the release/LTS process as the core group has chosen it could of course have been very specifically bound to 6 months of runway on one and the same v8 version, and then my thinking here is off...

[bnoordhuis]

@seeekr Not unless it's possible to upgrade without breaking API/ABI because that would break add-ons.

With 5.1, that might just be feasible; the API changes have been additive so far (i.e., semver-minor compatible) and the ABI breakage we can probably work around by floating a small patch.

[mgol]

With 5.1, that might just be feasible; the API changes have been additive so far (i.e., semver-minor compatible) and the ABI breakage we can probably work around by floating a small patch.

@bnoordhuis Does that still apply? V8 5.1 went stable 6 days ago.

I'm asking because V8 5.1 is the first V8 release which passes almost every test on the Kangax ES6 compat table with the exception for proper tail calls so if it was possible to get it into Node 6 it'd help a lot!

[bnoordhuis]

@mgol Looks like it. See ofrobots#23.

[lin7sh]

It's July already, any plan for the 5.1 release?

[rvagg]

see #7016 (comment) for more info on that