[0.18-rc][packager] Packager throws error "Cannot read property 'error' of null" instead of babel errors

[corbt]

This is to track the error first reported in #5188 and #5190. (The thread in #5188 got long because we weren't sure if it was related to the simultaneous but unrelated babel classProperties syntax change, so I'm consolidating here.)

There's a regression in the packager in 0.18-rc where babel syntax errors aren't passed through to the user, making it difficult to fix the underlying bugs. These are the error messages for the same bug running react-native bundle:

React Native 0.17

uncaught error Error: SyntaxError: /Users/kyle/proj/chimera/app/actions/auth.js: 'import' and 'export' may only appear at the top level (22:0)
  20 |
  21 |
> 22 | export function logOut() {
     | ^
  23 |   return {type: LOG_OUT};
  24 | }

React Native 0.18-rc

uncaught error Error: TypeError: Cannot read property 'error' of null
    at index.js:117:20
    at tryCallOne (/Users/kyle/proj/chimera/node_modules/react-native/node_modules/promise/lib/core.js:37:12)
    at /Users/kyle/proj/chimera/node_modules/react-native/node_modules/promise/lib/core.js:123:15
    at flush (/Users/kyle/proj/chimera/node_modules/react-native/node_modules/promise/node_modules/asap/raw.js:50:29)
    at doNTCallback0 (node.js:428:9)
TransformError: /Users/kyle/proj/chimera/app/actions/auth.js: Cannot read property 'error' of null
See logs /var/folders/j4/wct0sgyx0p9803_1nkhm3pzm0000gn/T/react-packager.log
    at SocketClient._handleMessage (SocketClient.js:139:23)
    at BunserBuf.<anonymous> (SocketClient.js:53:42)
    at emitOne (events.js:77:13)
    at BunserBuf.emit (events.js:169:7)
    at BunserBuf.process (/Users/kyle/proj/chimera/node_modules/react-native/node_modules/bser/index.js:289:10)
    at /Users/kyle/proj/chimera/node_modules/react-native/node_modules/bser/index.js:244:12
    at doNTCallback0 (node.js:428:9)
    at process._tickCallback (node.js:357:13)

[facebook-github-bot]

Hey corbt, thanks for reporting this issue!

React Native, as you've probably heard, is getting really popular and truth is we're getting a bit overwhelmed by the activity surrounding it. There are just too many issues for us to manage properly.

• If you don't know how to do something or something is not working as you expect but not sure it's a bug, please ask on StackOverflow with the tag react-native or for more real time interactions, ask on Discord in the #react-native channel.
• If this is a feature request or a bug that you would like to be fixed, please report it on Product Pains. It has a ranking feature that lets us focus on the most important issues the community is experiencing.
• We welcome clear issues and PRs that are ready for in-depth discussion. Please provide screenshots where appropriate and always mention the version of React Native you're using. Thank you for your contributions!

[ide]

cc @martinbigio, it looks like the packager has an error while trying to report errors.

[corbt]

For what it's worth I just tested running with the same syntax error on master and the babel error message appeared correctly, so it looks like this has already been fixed. It's probably just a question of figuring out what to cherry-pick into the 0.18 branch.

[satya164]

Also I recently noticed that packager no longer reports errors when it fails to import/require a module.

[floatinghotpot]

I also encounter the same issue on react-native 0.18.0-rc.

It's very easy to re-produce it, just create a new project, react-native init HelloReact, open the ios project with xcode, just build, it will report exact the same error.

If change package.json the react-native version from 0.18.0-rc to 0.17.0, and update the node-modules/react-native by rm -rf node-modules; npm install;, open ios project with xcode, build again, now build pass.

So, it must be something wrong with react-native v0.18.0-rc.

[etodanik]

I'm getting the exact same error by updating react 0.17 to 0.18.0-rc

[mkonicek]

Looks like this is something we should fix asap, I'll ping @martinbigio about it.

[mkonicek]

Thanks so much for using the rc everyone!

[tdzl2003]

Maybe it's caused by .babelrc from module react-deep-force-update which is incompatible with babel 6.x

[martinbigio]

This was already fixed on master last week. We need to cherry pick 5a4ee0b :)

[chshouyu]

thanks all, waiting for release.