Debugging: Dev Tools launch to 10.0.2.2 instead of localhost

[foggy1]

Is this a bug report?

Yes

Have you read the Contributing Guidelines?

yes

Environment

Environment:
OS: macOS High Sierra 10.13.3
Node: 8.7.0
Yarn: 1.3.2
npm: 5.6.0
Watchman: 4.7.0
Xcode: Xcode 9.2 Build version 9C40b
Android Studio: 2.3 AI-162.4069837

Packages: (wanted => installed)
react: 16.2.0 => 16.2.0
react-native: 0.53.0 => 0.53.0

Steps to Reproduce

1. Run app on Android.
2. Turn on Debug mode.
3. Bundler says "Launching Dev Tools..." and it opens chrome to http://10.0.2.2:8081/debugger-ui, which hangs because the debugger is on localhost.

Expected Behavior

I expect the debugger to open Chrome to localhost:8081/debugger-ui as it always has before I upgraded to version 0.53.0.

Actual Behavior

As mentioned, it opens to http://10.0.2.2:8081/debugger-ui, which is inoperable. Nothing ever loads. The Devtools middleware has the wrong host for some reason.

Reproducible Demo

You can literally react-native init a new app right now, and it will do this. Here's a package json of an app I just generated that has this issue

{
  "name": "testingtesting",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node node_modules/react-native/local-cli/cli.js start",
    "test": "jest"
  },
  "dependencies": {
    "react": "16.2.0",
    "react-native": "0.53.0"
  },
  "devDependencies": {
    "babel-jest": "22.2.2",
    "babel-preset-react-native": "4.0.0",
    "jest": "22.3.0",
    "react-test-renderer": "16.2.0"
  },
  "jest": {
    "preset": "react-native"
  }
}

It appears the app bundle is also being loaded from 10.0.2.2, but the debugger is not functioning at this host, which I'm guessing means that even if I navigate to a "working" debugger @ localhost, it's still not going to work. Credit to #17910 for first assuring me I was not crazy and this was a real issue.

Edit: Complete shot in the dark here, but could it have something to do with fa574c6 ? (happy to pr this with some direction, although I know at least part of the issue is in a separate file where it is also incorrect about the host when launching chrome).

[hramos]

(The bot might mark this as no-template, but it's because this issue is missing the first line from the template. Disregard)

[foggy1]

@hramos (edited to add it in)

[hramos]

Reopened, sorry about that. The bot is pretty naive when it comes to checking the template is followed, but it manages to catch the issues we really want to close immediately (where the whole template is deleted).

[inform880]

I'm getting this too on Windows. Really annoying.

Environment:
OS: Windows 10
Node: 6.11.1
Yarn: 1.3.2
npm: 5.6.0
Android Studio: 2.3 AI-162.4069837

[amcsi]

I'm getting this issue too on my new react-native project, although even manually going to http://localhost:8081/debugger-ui/ doesn't work.
I could swear this was working fine several weeks ago on a different react-native project.

Environment:
OS: Windows 10
Node: v9.4.0
npm: 5.6.0
Android Studio: 3.0.1

react-native-cli: 2.0.1
react-native: 0.53.0

[amcsi]

I can confirm that on my older react-native version 0.52.2 project work perfectly fine in terms of remote debugging.

The new 0.53.0 might be the cause of this issue.

[perseyMudzinga]

Go to http://localhost:8081/debugger-ui/ . Then stop remote js debugging and run your react native app again. Finally debug js remotely. Has worked for me.

[foggy1]

@perseyMudzinga Ok, that's good to know for when I need it. I was worried it wouldn't connect at all anymore.

Still, I'm wondering why the function that launches chrome in the middleware is wrong about the host (it thinks the host is, I believe, the location where the Android emulator runs, rather than localhost).