Autoprefixer version detection broken with latest execjs

[Aleks Clark]

With the following versions:

autoprefixer-rails (9.6.0)
GIT
  remote: https://github.com/rails/execjs.git
  revision: f6dc08c58ab4e1a467f64d471ee6e0127c2f14de
  ref: f6dc08c
  specs:
    execjs (2.7.0)

Autoprefixer seems to be using an invalid way of detecting node versions:

        if ExecJS.runtime == ExecJS::Runtimes::Node
          version = ExecJS.runtime.eval("process.version")
          first = version.match(/^v(\d+)/)[1].to_i
          if first < 6
            raise "Autoprefixer doesn’t support Node #{version}. Update it."
          end
        end

This code throws a TypeError, because process is null. If I comment out the check, autoprefixer seems to be functioning correctly.

[Andrey Sitnik]

What ExecJS runtime so you use?

[Aleks Clark]

Node, the vanilla one.

[Andrey Sitnik]

What Node.js version?

[Aleks Clark]

Oh sorry, v10.16.0. I think it also happens for node 8, but as part of my troubleshooting I've standardized on node 10 and it's tough to go back and test.

[Andrey Sitnik]

Hm. process is not null on Node.js 10. Maybe ExecJS uses different engine because of some issue?

[Aleks Clark]

Given the code there, it has to be calling `node` at least.... I've verified the shell's node version using `system('node --version')` and it's the correct version so...

…

On Wed, Jul 3, 2019 at 2:50 PM Andrey Sitnik ***@***.***> wrote: Hm. process is not null on Node.js 10. Maybe ExecJS uses different engine because of some issue? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#160?email_source=notifications&email_token=AAEUHHBA3LQPB7TMYCPCRYLP5T7IBA5CNFSM4H5IKU22YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODZFQESQ#issuecomment-508232266>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAEUHHEIFS5EP3E4VHUSH2TP5T7IBANCNFSM4H5IKU2Q> .

-- Aleks Clark cell: 775-391-6114

[Andrey Sitnik]

User can pass custom node path to ExecJS

[Andrey Sitnik]

We have a different question here. process should be always available on Node since it is part of Node’s stdlib.

[Aleks Clark]

I completely agree! I've created a minimal test case, can you try it? https://github.com/aleksclark/autoprefixer-bug-repro

[Aleks Clark]

Also, here's the version that does work:
https://github.com/aleksclark/autoprefixer-bug-repro/tree/working

As you can see, the difference is in using the latest version of execjs. The problem is that the latest release of execjs is quite old, and does not prefer node over nodejs

[Andrey Sitnik]

Do we need to fix the problem if it is related with old ExecJS and could be a bug, which they fixed?

[Aleks Clark]

The problem happens with new ExecJS (current master). Old execjs works fine. I think `process` not being available could be considered a bug in ExecJS, but I'm not sure if they consider that part of the public API.

…

On Wed, Jul 3, 2019 at 4:21 PM Andrey Sitnik ***@***.***> wrote: Do we need to fix the problem if it is related with old ExecJS and could be a bug, which they fixed? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#160?email_source=notifications&email_token=AAEUHHF5OWEOPQQGPU7AVV3P5UJ3ZA5CNFSM4H5IKU22YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODZFWXGY#issuecomment-508259227>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAEUHHAM5FCCCTV44YKL5NTP5UJ3ZANCNFSM4H5IKU2Q> .

-- Aleks Clark cell: 775-391-6114

[Andrey Sitnik]

I afraid that without stdlib I can garantee that other autoprefixer.js will work. It should have process calls in polyfills.

I am closing this issue, since I have no idea how to fix it.