V4.2, or V3.30?

[Mark Topinka]

Hi V8 people - I am considering embedding V8 in a programming project.  Which version would you recommend I use?  It seems unfortunately like there is very little publicly available sample code out there that works with version 4 of the V8 API (even a fair bit of the code on the official v8 "embedders guide" does not compile), so it's making learning the ropes a bit difficult... but I'm getting there.  What is the medium-term outlook for version 4.x - are we talking years until it's relatively stable and mature, or is it nearly ready to go?  On the one hand I would hate to base my project around a version of v8 that is going to be deprecated in the near future... on the other hand I would hate to base my code around a version of v8 that is still early in the development cycle with perhaps many hidden bugs still to be discovered and worked out.  Any words of wisdom would be appreciated.  Thanks.  -Mark

[Ben Noordhuis]

V8 branches are tied to Chrome/Chromium releases (3.28 -> Chrome 38,
3.29 -> Chrome 39, 3.30 -> Chrome 40, 4.1 -> Chrome 41, 4.2 ->
Chrome 42, etc.) and gets support and fixes for the lifetime of the
Chrome release, which I believe is six weeks. After that, the branch
is more or less abandoned; it may see the occasional bug fix but that
quickly tapers off.

If you want advice on what version of V8 to use: pick the one that
ships with the current Chrome stable and be prepared to upgrade
frequently. The V8 API can change between releases and may require
updates to your code.

Caveat emptor: the last few upgrades have been pretty smooth for us
(io.js) but there was a lot of churn in the ~1.5 years before that.
YMMV.

Hope that helps!

[Mark Topinka]

Thanks Ben, that was helpful.  

[Jakob Kummerow]

Right, Ben summed it up nicely. Our stability expectations are the same for every branch (once it starts shipping on Chrome stable, which is roughly 6 weeks after it's been created), and every branch's support period is also the same (another ~6 weeks until the next Chrome version goes on the stable channel). 

Regarding API churn, we try to keep the API stable, so most updates should be pretty smooth. We only change the API when there is a clear need/benefit to do so, and we document changes at bit.ly/v8-api-changes, including recommendations how to adapt embedder code (which are usually straightforward).

Just one more question:

On Sun, Feb 8, 2015 at 12:16 AM, Mark Topinka <mtop...@gmail.com> wrote: 

> a fair bit of the code on the official v8 "embedders guide" does not compile

Can you be more specific here? We do try to keep the embedders guide up to date, so reports on what's outdated are welcome.

As an additional resource, the samples in the source are guaranteed to compile.