Regression: Debugger stacktrace shows wrong source file

[hypest]

💥 Regression Report

Debugger stops at a debugger statement but the source file shown is wrong.

Last working version

Worked up to version: v0.58.6

Stopped working in version: v0.59.0, still happening in v0.59.1

To Reproduce

1. Create a new demo app via react-native init rn059 --version react-native@0.59.1
2. Add a debugger statement in the beginning of the render() method in App.js
3. Launch the app on Android react-native run-android
4. Enable debug mode via the in-app debug menu "Debug JS Remotely"
5. Notice the debugger coming up and stopping somewhere that doesn't look like the App.js file. In my case, the debugger stops at file:line ReactFabric-prod.js:7030

Expected Behavior

In step No5 above, the debugger should stop in file App.js, right at the beginning of the render() method where the debugger; statement is.

Code Example

Link to repo with example code: https://github.com/hypest/rn-059-stacktrace-mess-demo-app

Environment

$ react-native info
info
  React Native Environment Info:
    System:
      OS: macOS 10.14.3
      CPU: (12) x64 Intel(R) Core(TM) i9-8950HK CPU @ 2.90GHz
      Memory: 607.81 MB / 32.00 GB
      Shell: 4.4.19 - /usr/local/bin/bash
    Binaries:
      Node: 8.11.3 - ~/.nvm/versions/node/v8.11.3/bin/node
      Yarn: 1.10.1 - ~/.nvm/versions/node/v8.11.3/bin/yarn
      npm: 6.3.0 - ~/.nvm/versions/node/v8.11.3/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.0, macOS 10.14, tvOS 12.0, watchOS 5.0
      Android SDK:
        API Levels: 23, 26, 27, 28
        Build Tools: 19.1.0, 23.0.1, 26.0.2, 26.0.3, 27.0.3, 28.0.2, 28.0.3
        System Images: android-23 | Google APIs Intel x86 Atom_64, android-26 | Google Play Intel x86 Atom, android-28 | Google Play Intel x86 Atom, android-28 | Google Play Intel x86 Atom_64
    IDEs:
      Xcode: 10.0/10A255 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.8.3 => 16.8.3
      react-native: 0.59.1 => 0.59.1
    npmGlobalPackages:
      create-react-native-app: 1.0.0
      react-native-cli: 2.0.1
      react-native-create-library: 3.1.2
      react-native-git-upgrade: 0.2.7

[yurykorzun]

After updating to 0.59.1, I can't debug properly on Android, it looks like produced source maps are all messed up. Breakpoints are off and triggering code in wrong files. Still works for iOS though.
It probably has something to do with the JSC update.

[yurykorzun]

Probably related #6946

[oferRounds]

Experiencing this also

[kelset]

Thanks @yurykorzun for the investigation! Copying here for relevance:

The metro bundler is producing a wrong source map on Android in 0.59.1 and 0.59.0. At least it is consistently happening in my React Native project, but works fine on iOS. I tried to disable JS deltas, it doesn't help.

It could be related to JSC upgrade, but because I don't know how source maps are generated and mapped to running javascript on a device, I don't know exactly what is causing it.

Metro is using this package for generating a source map npmjs.com/package/source-map

[kelset]

It would be better to actually post this issue in the metro repository - can anyone do that? Afterwards we can close this and move the conversation there.

[yurykorzun]

It would be better to actually post this issue in the metro repository - can anyone do that? Afterwards we can close this and move the conversation there.

Done facebook/metro#380