Initializing task consumer 'expo.modules.location.a.b' failed.

🐛 Bug Report

Environment

Expo CLI 2.14.0 environment info:
    System:
      OS: macOS 10.14.4
      Shell: 5.3 - /bin/zsh
    Binaries:
      Node: 11.8.0 - /usr/local/bin/node
      Yarn: 1.13.0 - /usr/local/bin/yarn
      npm: 6.8.0 - /usr/local/bin/npm
    IDEs:
      Android Studio: 3.3 AI-182.5107.16.33.5264788
      Xcode: 10.1/10B61 - /usr/bin/xcodebuild
    npmPackages:
      @storybook/react-native: ^4.1.4 => 4.1.6 
      expo: ^32.0.0 => 32.0.1 
      react: 16.5.0 => 16.5.0 
      react-native: https://github.com/expo/react-native/archive/sdk-32.0.0.tar.gz => 0.57.1 

Steps to Reproduce

Define task in App.js file (not in Class)

TaskManager.defineTask('TEST', ({ data: { locations }, error }) => {
  console.log(locations)
  Alert.alert('New location')
  if (error) {
    console.log(error.message)
    return
  }
  console.log('Received new locations', locations)
})

Next, in componentDidMount of App, we start tracking location:

await Location.startLocationUpdatesAsync('TEST', {
      distanceInterval: 50,
      accuracy: Location.Accuracy.Highest,
    })

Expected Behavior

Starts tracking location updates

Actual Behavior

Crashes and throws Error: Initializing task consumer 'expo.modules.location.a.b' failed.

IMPORTANT NOTE:

This crash only happens in production, it works fine in development.

[xanderdeseyn]

Hi guys, I figured out what the problem was: Proguard. Add this rule to your proguard-rules.pro file and it will work:

-keep class expo.modules.location.** { *; }

If you look at the source, some voodoo is happening with retrieving the name of the constructor and calling that (which proguard messes up with their obfuscation).

I think this should be mentioned in the docs.

[github-actions[bot]]

This issue was closed because it has been inactive for 7 days since being marked as stale. Please open a new issue if you believe you are encountering a related problem.