Is this a bug report?

Yes

Have you read the Contributing Guidelines?

Yes

Environment

$ react-native info

Environment:
  OS:  macOS Sierra 10.12.6
  Node:  8.6.0
  Yarn:  1.2.0
  npm:  5.3.0
  Watchman:  4.9.0
  Xcode:  Xcode 9.0 Build version 9A235
  Android Studio:  Not Found

Packages: (wanted => installed)
  react: 16.0.0-beta.5 => 16.0.0-beta.5
  react-native: 0.49.3 => 0.49.3

Steps to Reproduce

1. Upgraded RN from 0.48 to 0.49
2. My local forked package of react-native-webview-bridge broke, see below under Actual Behavior

Expected Behavior

react not needed as a dependency in a local package (my fork of https://github.com/alinz/react-native-webview-bridge), nor is my hack fix needed to import directly from main app's node_modules/, and bundling goes through without error when react-native run-ios is run.

Actual Behavior

From yarn outdated of my local package:

react-native-webview-bridge       0.33.0        exotic        exotic dependencies ../react-native-webview-bridge-RN0.40

With RN up to 0.48, my app's inclusion and import of react-native-webview-bridge like above works without issue. The package has no dependency itself of react.

Since upgrading to RN 0.49.3, this bundling error occurs on running react-native run-ios:

Unable to resolve module `react` from [package index]: Module does not exist in the module map

Then I added react as a dependency in package.json, like so:

  "devDependencies": {
    "react": "16.0.0-beta.5"
  },

Bundler will then error on Invariant violation: ... You may have multiple copies of React loaded.

A bit of a damned if I do, damned if I don't on getting react dependency in inside the package? Either none found, or there's 2 copies.

I made a hack fix as workaround around both errors, by replacing all instances inside the package of

var React = require('react');

with

var React = require('[HOMEDIR]/Documents/code/[PROJECT]/node_modules/react');

I hardcoded the react path to the exact copy of react my main app (PROJECT) imports, which avoids not able to resolve module react. I have to alter a sub module inside the package too: react-native-webview-bridge-RN0.40/node_modules/create-react-class/index.js which imports React, which makes this doubly hacky and prone to overwritten.

If there's a less dirty workaround, I'm all ears.

This is a repost of facebook/metro#74 as this involves React not being resolved and maybe a RN issue?