Node.js 8.0 and v8 5.9

[vsemozhetbyt]

v8/node/vee-eight-lkgr has just updated v8 to 5.9 with Ignition+TurboFan turned on by default.

Node.js 8.0 has a chance to be released with at most v8 5.8.

Would v8 5.9 be considered as semver-major due to the new interpreter/compiler pipeline? Has it a chance to be added into Node.js 8.0 later?

[targos]

Would v8 5.9 be considered as semver-major due to the new interpreter/compiler pipeline?

IMO the new pipeline itself does not make the update semver-major. No code should be broken by the switch (if it happens, it's a V8 bug).

Has it a chance to be added into Node.js 8.0 later?

It depends on multiple things. Somebody would have write a patch to make the update ABI/API compatible with 5.7 or 5.8 (depending on the version that will ship with Node 8).
I think performance will also be an important thing to check.

[vsemozhetbyt]

Benchmarks (to be continued): #11851

[italoacasas]

@Fishrock123 you ask yesterday on IRC about this.

[jasnell]

Beyond the normal ABI compatibility concerns, one of the key considerations for landing any v8 greater than 5.8 in 8.x will be whether or not the new pipeline is something we want to support in the LTS line post October. Up to this point, several of the @nodejs/v8 folks have been urging restraint moving up while they make sure everything is good.