Metro: [BUG] Metro still can't build on windows

[gengjiawen]

Repro: Just build RNTester on windows.
Related issue: https://github.com/facebook/react-native/issues/20353, https://github.com/facebook/metro/issues/181.
From what I test, 0.42.1 works. But not 0.42.2, 0.43.1. 0.43.2., 0.43.3.
You can also see the appveyor build log: https://ci.appveyor.com/project/gengjiawen/react-native/build/1.0.22/job/it491en7tm6r69cq.

D:\Developer\react-native\local-cli\cliEntry.js:30
import type {CommandT} from './commands';
       ^^^^

SyntaxError: Unexpected identifier
    at new Script (vm.js:74:7)
    at createScript (vm.js:246:10)
    at Object.runInThisContext (vm.js:298:10)
    at Module._compile (internal/modules/cjs/loader.js:657:28)
    at Module._compile (D:\Developer\react-native\node_modules\pirates\lib\index.js:83:24)
    at Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Object.newLoader [as .js] (D:\Developer\react-native\node_modules\pirates\lib\index.js:88:7)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[rafeca]

Thanks for the information @gengjiawen !

This means that we reintroduced the issue in one of the following commits: https://github.com/facebook/metro/compare/v0.42.1...v0.42.2

@pvdz The most probable thing that can be causing this issue is the upgrade to babel7-beta.54 + the revert of the windows dir normalization.

@gengjiawen can you test if v0.43.3 + a revert of https://github.com/facebook/metro/commit/0b70c9a5db55deb1bd21add57972d66c20c25e2e fixes the issue? if not can test it tomorrow (I'm in European time)

[gengjiawen]

@rafeca is there an easy way I can test this. There are many packages in metro. And How do I replace the metro version in react native.

[rafeca]

From what I test, 0.42.1 works. But not 0.42.2, 0.43.1. 0.43.2., 0.43.3.

uhm I'm confused now, how were you able to test that 0.42.1 works but not 0.42.2 without replacing the metro version in React Native?

[rafeca]

It looks like the root issue comes from 0b70c9a, I'm reverting it and afterwards we're going to release a new version of Metro.

Thanks @gengjiawen for helping me debug it!

[rafeca]

We've just published Metro v0.43.4 which should fix the windows issues: https://github.com/facebook/metro/releases/tag/v0.43.4

[LinusU]

is there an easy way I can test this.

Just for future reference, I personally used something like this to test with other versions:

"resolutions": {
  "**/buck-worker-tool": "0.43.4",
  "**/metro": "0.43.4",
  "**/metro-babel-register": "0.43.4",
  "**/metro-babel7-plugin-react-transform": "0.43.4",
  "**/metro-cache": "0.43.4",
  "**/metro-config": "0.43.4",
  "**/metro-core": "0.43.4",
  "**/metro-memory-fs": "0.43.4",
  "**/metro-minify-uglify": "0.43.4",
  "**/metro-react-native-babel-preset": "0.43.4",
  "**/metro-resolver": "0.43.4",
  "**/metro-source-map": "0.43.4",
}

Add that to your package.json, and then run yarn.

You can also use the following snippet to force a specific version of Babel:

"resolutions": {
  "**/@babel/code-frame": "7.0.0-beta.48",
  "**/@babel/core": "7.0.0-beta.48",
  "**/@babel/generator": "7.0.0-beta.48",
  "**/@babel/helper-annotate-as-pure": "7.0.0-beta.48",
  "**/@babel/helper-builder-binary-assignment-operator-visitor": "7.0.0-beta.48",
  "**/@babel/helper-builder-react-jsx": "7.0.0-beta.48",
  "**/@babel/helper-call-delegate": "7.0.0-beta.48",
  "**/@babel/helper-define-map": "7.0.0-beta.48",
  "**/@babel/helper-explode-assignable-expression": "7.0.0-beta.48",
  "**/@babel/helper-function-name": "7.0.0-beta.48",
  "**/@babel/helper-get-function-arity": "7.0.0-beta.48",
  "**/@babel/helper-hoist-variables": "7.0.0-beta.48",
  "**/@babel/helper-member-expression-to-functions": "7.0.0-beta.48",
  "**/@babel/helper-module-imports": "7.0.0-beta.48",
  "**/@babel/helper-module-transforms": "7.0.0-beta.48",
  "**/@babel/helper-optimise-call-expression": "7.0.0-beta.48",
  "**/@babel/helper-plugin-utils": "7.0.0-beta.48",
  "**/@babel/helper-regex": "7.0.0-beta.48",
  "**/@babel/helper-remap-async-to-generator": "7.0.0-beta.48",
  "**/@babel/helper-replace-supers": "7.0.0-beta.48",
  "**/@babel/helper-simple-access": "7.0.0-beta.48",
  "**/@babel/helper-split-export-declaration": "7.0.0-beta.48",
  "**/@babel/helper-wrap-function": "7.0.0-beta.48",
  "**/@babel/helpers": "7.0.0-beta.48",
  "**/@babel/highlight": "7.0.0-beta.48",
  "**/@babel/plugin-external-helpers": "7.0.0-beta.48",
  "**/@babel/plugin-proposal-class-properties": "7.0.0-beta.48",
  "**/@babel/plugin-proposal-object-rest-spread": "7.0.0-beta.48",
  "**/@babel/plugin-proposal-optional-chaining": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-class-properties": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-dynamic-import": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-flow": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-jsx": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-nullish-coalescing-operator": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-object-rest-spread": "7.0.0-beta.48",
  "**/@babel/plugin-syntax-optional-chaining": "7.0.0-beta.48",
  "**/@babel/plugin-transform-arrow-functions": "7.0.0-beta.48",
  "**/@babel/plugin-transform-async-to-generator": "7.0.0-beta.48",
  "**/@babel/plugin-transform-block-scoping": "7.0.0-beta.48",
  "**/@babel/plugin-transform-classes": "7.0.0-beta.48",
  "**/@babel/plugin-transform-computed-properties": "7.0.0-beta.48",
  "**/@babel/plugin-transform-destructuring": "7.0.0-beta.48",
  "**/@babel/plugin-transform-exponentiation-operator": "7.0.0-beta.48",
  "**/@babel/plugin-transform-flow-strip-types": "7.0.0-beta.48",
  "**/@babel/plugin-transform-for-of": "7.0.0-beta.48",
  "**/@babel/plugin-transform-function-name": "7.0.0-beta.48",
  "**/@babel/plugin-transform-literals": "7.0.0-beta.48",
  "**/@babel/plugin-transform-modules-commonjs": "7.0.0-beta.48",
  "**/@babel/plugin-transform-object-assign": "7.0.0-beta.48",
  "**/@babel/plugin-transform-parameters": "7.0.0-beta.48",
  "**/@babel/plugin-transform-react-display-name": "7.0.0-beta.48",
  "**/@babel/plugin-transform-react-jsx": "7.0.0-beta.48",
  "**/@babel/plugin-transform-react-jsx-source": "7.0.0-beta.48",
  "**/@babel/plugin-transform-regenerator": "7.0.0-beta.48",
  "**/@babel/plugin-transform-shorthand-properties": "7.0.0-beta.48",
  "**/@babel/plugin-transform-spread": "7.0.0-beta.48",
  "**/@babel/plugin-transform-sticky-regex": "7.0.0-beta.48",
  "**/@babel/plugin-transform-template-literals": "7.0.0-beta.48",
  "**/@babel/plugin-transform-unicode-regex": "7.0.0-beta.48",
  "**/@babel/register": "7.0.0-beta.48",
  "**/@babel/template": "7.0.0-beta.48",
  "**/@babel/traverse": "7.0.0-beta.48",
  "**/@babel/types": "7.0.0-beta.48"
}