process.env.PATH missing in tests on Windows

[emilis-ideait]

TL;DR: { ...process.env }.PATH is undefined on Windows. Probably need to fix lib/fork.js.

Tried to do:

I upgraded Ava from 2.4.0 to 4.2.0 in our internal project and tests started failing on our Windows build server with this message:

Error: Cannot read property 'split' of undefined TypeError: Cannot read property 'split' of undefined
          at Object.findInPath (...\node_modules\selenium-webdriver\io\index.js:215:45)

The failing code was trying to execute process.env['PATH'].split().

I added some console.log() statements to our tests and found that process.env.PATH is missing, but process.env.Path is available instead.

Expected:

process.env.PATH available in tests on Windows.

Investigation:

1. process.env.PATH is problematic in Node.js on Windows. See related issues: https://github.com/nodejs/node/issues?q=is%3Aissue+process.env.PATH+

2. I suspect this code (I'm not familiar with Ava codebase) in lib/fork.js:

   • env: {NODE_ENV: 'test', ...process.env, ...options.environmentVariables},

This minimal code in Node.js on windows shows what's happening with ...process.env:

Temporary workaround for other users

I renamed Path to PATH in Windows System Variables.

(Settings -> System -> About -> Advanced system settings -> Environment Variables...)

This fixed the issue with the tests failing, but now the tests get both process.env.PATH AND process.env.Path, which is different to how it works in Node.js (you only see Path when printing out process.env).

[novemberborn]

...process.env is meant to do a shallow copy of the process.env object. However the Node.js documentation says this:

On Windows operating systems, environment variables are case-insensitive.

https://nodejs.org/api/process.html#processenv

This implies some magic that would not survive the copying, though presumably at least one version of the variable is copied. That said, I'd think within the tests Node.js should again make the variables case-insensitive.

What Node.js version are you using? And could you share your AVA config? Could you try disabling AVA's use of worker threads to see if that helps? What does console.dir({...process.env}) print?

[emilis-ideait]

I am using Node.js v14.19.1 on Windows.

Turning off workerThreads helped.

I created a small repository to test the issue: https://github.com/emilis-ideait/ava-process-env-path-on-windows

npm test in this repository fails:

npm run test-no-worker-threads succeeds:

I should be able to test with Node.js v16 on Windows in a couple of weeks.

[novemberborn]

My impression is that somehow in worker threads process.env doesn't behave the same as in the main thread. This seems like unexpected behavior on Node.js part.