Support python3

[ry]

We are heavily dependent on V8, which in turn is heavily dependent on Chromium tooling, which does not support Python3 and has only recently begun conversion -
https://bugs.chromium.org/p/chromium/issues/detail?id=942720
https://bugs.chromium.org/p/v8/issues/detail?id=8594
nodejs/node#24512

[hayd]

I'm happy to do this, I think it'll be straightforward, but it's probably worth waiting for v8 support to be completed.

[cclauss]

it's probably worth waiting

Not! Python 3 was released 11 years ago and there are 113 days until Python 2 end of life. Please do work in parallel, not serial to be ready before yearend. It would be great if someone could get v8/v8#33 and v8/v8#34 pushed and landed upstream.

[hayd]

@cclauss I bet I can do the deno part of the port in under an hour, certainly less than a day. I've ported large modules to python 3... deno is very small. I suppose it would help to enumerate precisely which python v8 scripts need to be ported in order for deno to work, I can do that.

[cclauss]

Not a question of your skills. I have been impressed. It is just a question of putting lots of concentrated pressure on the few bottlenecks that are not ready so we create a compelling reason to act. We want to create the impression that the train is leaving the station without the laggards onboard.

[bmsdave]

Hi!
I send this PR from @AgentJ08 to https://chromium-review.googlesource.com/c/v8/v8/+/1864942

[kt3k]

https://travis-ci.com/bmsdave/v8/builds/132539826
Does this mean v8 can be built with python 3?

[cclauss]

@bmsdave Can V8 be built with Python 3?

[hayd]

No: bmsdave/v8@845d137

[cclauss]

https://travis-ci.com/bmsdave/v8/builds Seems to be passing the lint steps. Where does the V8 build on Py3 break down?

[hayd]

The script it's running is true, the Travis build is not running any build/tests other than flake8...

[cclauss]

Exactly. So where can we see the build failing on Python 3?

[hayd]

Sorry I was answering (no) to @kt3k :

https://travis-ci.com/bmsdave/v8/builds/132539826
Does this mean v8 can be built with python 3?

It could be that the build works with just the syntax changes (but I would be surprised).

I think we need to compile and run with gm.py, see https://v8.dev/docs/test.

[kitsonk]

Closing in favour of #8223 (plus we have #7779).