ansible: install multiple versions of xcode on build machines

[gdams]

we should install multiple versions of xcode on our build machines and implement xcode-select to allow us to switch between versions easily for builds. CC @mhdawson

[mhdawson]

This may be a blocker for updating the v8 level @targos can you post the related issue here?

[targos]

nodejs/node-v8#63
nodejs/node#21079 (comment)

[mhdawson]

@gdams can you comment with how long you think this might take. From nodejs/node#21079 (comment) sounds like 6.8 becomes stable on the Google side on the 24th.

[mhdawson]

This is also related #1264

[gdams]

I'm going to play around with this over the weekend. The main issue that I have right now is that it means that we will have to install non-default versions of xcode on macOS distributions which is much harder to source. We might have to stick an xcode dmg file on the public files server that we have for a few dependencies.

[gdams]

gcc versions for reference:

macOS 10.10

administorsMac3:~ administrator$ gcc --version
Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 7.0.2 (clang-700.1.81)
Target: x86_64-apple-darwin14.5.0
Thread model: posix

macOS 10.11

adminisorsMac14:~ administrator$ gcc --version
Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin15.0.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

[gdams]

hmm so it appears that 6.8 requires Xcode 8.x or higher but unfortunately Xcode 8.x is not supported on macOS 10.10 and these is no workaround for this. We therefore will have to build on macOS 10.11.5 or higher.

https://en.wikipedia.org/wiki/Xcode#8.x_series

[mhdawson]

@gdams thanks for figuring that out.

That has 2 potential issues in respect to V8 6.8, our current support statement is

macOS | Tier 1 | >= 10.10 | x64

If we have to build on 10.11 I think that means we'd have to change it to >= 10.11 which I'm not sure we can do in 10.x. I think we could build on 10.11 and it would still run on 10.10, but people building themselves could no longer build on 10.10 which could force them to upgrade. @nodejs/build what's your interpretation of whether we can change this in shipped release line?

We'll need new machines to build on. We can start using MacStadium but as mentioned there is a potential issue on that front.

@gdams can you setup a machine in MacStadium we can use for the release machine so we are ready to go when we decide what to do.

[gibfahn]

@nodejs/build what's your interpretation of whether we can change this in shipped release line?

I don't think we have ever given a guarantee of what level you can build Node on, so I'd be fine with changing that. I think I remember @bnoordhuis saying this at some point.

It'd be difficult to be sure that it actually runs on 10.10 though if we can't build on that level.

[Trott]

If it matters, 10.10 is unsupported by Apple as of September 2017, so it may not be a big deal to stop supporting it...

[mhdawson]

@nodejs/build any issues if we start building master/nightlies on 10.11? The implications might be:

1. People will soon not able to build on 10.10 anymore (since we know a change is coming in V8 6.8 that will prevent this)
2. We will have taken a dependency on MacStadium for releases (at least nightlies)

After we answer this question we'll then have to separately decide if we are ok with the same for 10.X, but doing this for master should be the easier decision.