Next 11.0.1 forces wrong line-endings on Windows in next-env.d.ts

What version of Next.js are you using?

@latest v11.0.1

What version of Node.js are you using?

@latest-ish v15.14.0

What browser are you using?

Chrome

What operating system are you using?

Windows 10 x64

How are you deploying your application?

Vercel

Describe the Bug

Next 11 writes next-env.d.ts all the time, but it uses *nix style line endings:

Expected Behavior

*Don’t manually force line-endings to CR *Respect .gitattributes file (explictly specificing CR LF) *Respect operating-system preference (CR LF on Windows)

To Reproduce

1. Throw Prettier errors using this configuration:

prettier.config.js

module.exports = {
  // These settings are handled in .editorconfig:
  tabWidth: 2, // indent_size = 2
  useTabs: false, // indent_style = space
  endOfLine: "lf", // end_of_line = lf
  semi: false, // default: true
  singleQuote: false,
  printWidth: 80,
  trailingComma: "es5",
  bracketSpacing: true,
}

.eslintrc.js

module.exports = {
  extends: [
    "eslint:recommended",
    "plugin:prettier/recommended",
  ],
  rules: {
    "prettier/prettier": "error",
  },
}

Preferable solution: Ask some of your engineers to switch to Windows full-time

[ijjk]

Hi, this has been updated in v11.1.3-canary.25 of Next.js, please update and give it a try!

[DoctorDerek]

@thadeucity In my projects I use .editorconfig, prettier.config.js, and .gitattributes to all force LF, because otherwise ESLint will error on CR/LF line ending with the setting prettier/prettier: "error".

The .editorconfig will force LF on file save in VS Code (while the Prettier VS code extension will not), but the files will still get cloned down with CRLF and all have errors (until running eslint --fix . or prettier --write .) without the .gitattributes file.

(For anyone else having this issue, I posted a thorough discussion of it over in @tailwindlabs/tailwindcss#3760.)

For this .next-env.d.ts bug on Windows, here’s the relevant code using os.EOL.

@packages/next/lib/typescript/writeAppTypeDeclarations.ts: https://github.com/vercel/next.js/blob/26105e285de056ff59ea3597a4b2d1293f82b5cf/packages/next/lib/typescript/writeAppTypeDeclarations.ts#L1-L27

To fix this, I guess the system would have to query the Prettier.config.js (or other named files, i.e. by importing prettier if found and using its configuration file as is done here: https://github.com/prettier/prettier-eslint/blob/c62769ef430749fb9650c7e1d05f5cf7442a48a2/src/index.js#L255-L263

This would seem to start becoming quite a difficult problem, though, since line endings can be set in .editorconfig, prettier.config.js, .prettierrc, .eslintrc (not recommended due to compatibility issues with VS Code Prettier extension), etc., not to mention .gitattributes.