.babelrc and eject script

[dbismut]

Hey - I'm very new (or at least I'm far from understanding everything) but working on a fork of this project using inferno, I'm running into an issue with the eject script, namely that the .babelrc file can't be found.

Looking at the code of react-scripts and specifically this line, it looks like the eject script looks for a file called .babelrc (notice the dot).

During this commit .babelrc was renamed to babelrc.

I'm not running into bugs with create-react-app, but I was wondering if everything was normal?

[gaearon]

Good catch. I don’t understand why end-to-end test passes on master. 😳

This doesn’t affect our users because they’re on 0.9.x branch. That’s where stable releases are, until 0.10 is ready. I would not recommend anyone to use code in master of this repo right now.

[gaearon]

(The fix would be to hardcode Babel and ESLint "configs" since they're one liners.)

[gaearon]

This is showing up in Travis logs:

(node:3029) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: ENOENT: no such file or directory, open '/tmp/tmp.F2nYJH2DAJ/test-app/node_modules/react-scripts/.babelrc'
(node:3029) DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

We should somehow enable this behavior sooner in end-to-end test.

And I don't understand how the project still builds after ejecting on CI without those fields..

[gaearon]

OK, this is embarrassing.

Our end-to-end test doesn’t verify that ejection actually happened. So we get an unhandled Promise rejection, ejecting stops, but since it doesn’t exit with an error, the project is still in half-working state, and so it passes the rest of the end-to-end test.

If you’d like to help, please send a PR that:

1. Makes the end-to-end tests (files in tasks/*.sh) crash on unhandled rejection. Since you probably can’t enforce that from a shell file, maybe we should just do that in every scripts/*.js file. I’m not sure how to opt into this though.

2. Verify that a crash like this causes eject to exit with non-zero code. This way we can catch ejection errors in end-to-end tests instead of ignoring them.

3. Fix the actual issue here. This would mean replacing reads from those files and further assignments with something simple like

appPackage.babel = {presets: 'react-app'};
appPackage.eslintConfig = {extends: 'react-app'};

[dbismut]

Hey, thanks for investigating so quickly! I'm not sure I'm the right man for this since I've never done tests in my life (I know this is wrong, but I'll have a look and make up for it), but I was curious on point 3 why we should not read from the file and just change .babelrc to babelrc?

Unless there is absolutely no reason in the future to add other lines to babelrc and eslintrc?

[Timer]

@dbismut you can do it! We're here to help. 😄

As for point three, we simply use these files for the ejection process -- they're not used internally by react-scripts (probably why renamed, to not make devs confused when they edit them and it doesn't change anything).
We can get rid of these because they're only used in one location.

---

Looks like throwing on an unhandled rejection will be the default behavior in Node 8.

For now, looks like we can opt-in like so:

process.on('unhandledRejection', err => {
  throw err;
});

We should probably add this to scripts/*.sh, not tasks/*.sh since it will become the new default.

A PR implementing 1 and 2 would be a great start (to see an actual failure), we can talk about 3 then.

Thanks so much!

[gaearon]

@dbismut Can you verify whether the fix in #1810 helps?

[dbismut]

@gaearon It does fix it!

[Timer]

@dbismut did you want to send a PR adding the unhandled rejection throwing to scripts?