withPrompts freezes the command line on some windows versions on node 10.2+

[Autre31415]

This was quite a journey to triage!

Basically if you're running yeoman tests on Appveyor on node 10.2 or higher and you use withPrompts in a test the CI will hang indefinitely until it crashes.

See example here
And some tests here

If you're running a Windows 10 machine this will not happen locally, but if you run the tests in Windows 7 you'll see that same indefinite freeze that Appveyor fell victim to.

[mischah]

Thanks for reporting this. I wonder if there is anything we can do about this 🤔

[Autre31415]

I did some quick debugging on this and drew the conclusion that the freeze is caused by a step in the yeoman-environment module, though I'm not able to replicate it when using a generator in Windows 7.

[luboskmetko]

I've just encountered the same issue on Windows 10 after upgrading to Node v10.13.0 recently. The test includes withPrompts. After downgrading to Node v8.12.0, the tests work again.

[Autre31415]

I've just encountered the same issue on Windows 10 after upgrading to Node v10.13.0 recently. The test includes withPrompts. After downgrading to Node v8.12.0, the tests work again.

Back when I first noticed this node 10.2 was the latest and I found it odd that older versions worked (Including any 10.x prior to 10.2). Do your tests work on 10.1?

[vajahath]

I also faced this. I'm recording here a few of my quick findings (Windows 10/Node 13).

So when the generator is ran with this yeoman-test module, looks like the prompt promise is not getting resolved.

(generator code)

class MyGen extends Generator {
  constructor(args, opts) {
    super(args, opts);
  }

  public async prompting() {
    const qns = [
      {
        type: "input",
        name: "name",
        message: "Your project name"
      }
    ];

    // working
    console.log("before prompting");

    // the problem seems to be here..
    this.answers = await this.prompt(qns);

    // not working
    console.log("prompt response resolved");
  }
}

Looking at the source (yeoman-generator\lib\index.js) of this issue causing function, found the this.env.adapter.prompt(questions) is not getting resolved.

prompt(questions) {
  questions = promptSuggestion.prefillQuestions(this._globalConfig, questions);
  questions = promptSuggestion.prefillQuestions(this.config, questions);

  return this.env.adapter.prompt(questions) // this promise is not resolving
    .then(answers => {
      if (!this.options['skip-cache'] && !this.options.skipCache) {
        promptSuggestion.storeAnswers(this._globalConfig, questions, answers, false);
        promptSuggestion.storeAnswers(this.config, questions, answers, true);
      }

      return answers;
    });
}

The source of this this.env.adapter.prompt(questions) looks like coming from
yeoman-test\lib\adapter.js.

TestAdapter.prototype.prompt = function(questions, cb) {
  /**
   * the following line looks like causing an
   * un resolved promise.
   */ 
  var promise = this.promptModule(questions);
  promise.then(cb || _.noop);

  return promise;
};

Everything works fine when Node 8 is used.

What is even stranger is when I tried to debug this issue with VS Code Debugger (using jest) with node 10, this worked fine and I couldn't reproduce it. But without debugger this issue is there again.

Update: found these tests are passing in GitHub Actions environment (Windows 10/ Node 13). strange.

[mshima]

@vajahath could get to reproduce this error in GitHub Actions?

[vajahath]

@mshima I couldn't reproduce this at GitHub Actions, which is strange! When I locally run these tests with node 13, it fails and passes at GitHub Actions' environment.

[mshima]

@vajahath this seems to be a node.js bug that is affecting inquirer SBoudrias/Inquirer.js#767
There is a PR that should workaround this bug, but must be validated.
I got a windows machine to trace yeoman-generator problem. Don’t have it anymore.
If you could validade that PR on a windows machine. Running inquirer tests and check functionality.

[mshima]

Fixed on inquirer.

[ronaldborman]

For those who try to use the Inquirer fix, it is reverted because of side effects. See SBoudrias/Inquirer.js#899.

[mshima]

I didn’t test, but seems to be fixed on node >= 14.6.0.