Add option to filter invalid arguments from execArgv when launching worker threads

[shellscape]

Please provide details about:

• What you're trying to do

I'm using a task runner that's constructing Node commands as such:

node --title svc-test:test ../../node_modules/ava/entrypoints/cli.mjs

• What happened

--title is not valid for creating a worker.

✘ Internal error
  Error [ERR_WORKER_INVALID_EXEC_ARGV]: Initiated Worker with invalid execArgv flags: --title
  Error [ERR_WORKER_INVALID_EXEC_ARGV]: Initiated Worker with invalid execArgv flags: --title
      at new NodeError (node:internal/errors:399:5)
      at new Worker (node:internal/worker:192:13)
      at createWorker (file:///Users/user/code/test/node_modules/.pnpm/ava@5.3.0/node_modules/ava/lib/fork.js:24:12)
      at loadFork (file:///Users/user/code/test/node_modules/.pnpm/ava@5.3.0/node_modules/ava/lib/fork.js:84:39)
      at pMap.concurrency.concurrency (file:///Users/user/code/test/node_modules/.pnpm/ava@5.3.0/node_modules/ava/lib/api.js:289:20)
      at file:///Users/user/code/test/node_modules/.pnpm/p-map@5.5.0/node_modules/p-map/index.js:141:26

• What you expected to happen

I'd expect that Ava would filter out options that would throw. Probably related nodejs/node#41103 (comment)

[bojavou]

I also want to do this! Would like to access GC control in my tests, with one of these options:

• --expose-gc
• --allow-natives-syntax

Temporarily I disabled workers to get it running.

export default {
  verbose: true,
  workerThreads: false
}

[novemberborn]

@shellscape I'm not sure what the best way out of this is.

We do explicitly forward the execArgv, maybe that is not necessary? You can use the nodeArguments option to specify additional arguments.

I think not forwarding execArgv would be a breaking change so now's the time.

[novemberborn]

Looks like the explicit process.execArgv reference was added for a debugging feature back in 2016: #874

The problem though is we need to pass a flag to enable source maps, which means we can never inherit the default execArgv:

ava/lib/fork.js

Line 17 in 6398772

const additionalExecArgv = ['--enable-source-maps'];

Filtering the list seems problematic since it may change between Node.js releases, unless there's a third party dependency we can use for that.

[shellscape]

Yeah it's a tricky one. This is a documented issue across the Node ecosystem as well - it's a gap between process and workers in Node and so far the Node core team won't address it. The tool I was using has since removed use of --title from their code, so my immediate cause is fixed. And that's probably the process for most users - asking their tooling authors (or their own team) to remove that parameter until Node itself acts on some compatibility. Filtering will probably work in the near term, so probably not so problematic until it breaks (if it ever does) again.

If that doesn't feel right, adding to the docs about this edge case would probably suffice.

[novemberborn]

Having thought about this some more, we could add a filterExecArgv() through the ava.config.* files. It could receive the individual values allowing end-users to discard incompatible ones.

As for documentation, how about this? #3215

[novemberborn]

See also #3025.

[shellscape]

Those are both great. I think we're in good shape to close this.

[novemberborn]

I think a filter function could be a useful addition, so I'll leave this open for now.