RCTImagePickerManager requires main queue setup warning

🐛 Bug Report

On startup, app reports a yellow box warning: Warning Module RCTImagePickerManager requires main queue setup since it overrides init but doesn’t implement ``requiresMainQueueSetup`. In a future release React Native will default to initializing all native modules on a background thread unless explocitly opted-out of.

Stack:

logIfNoNativeHook
RCTLog.js:34:8
__callFunction
MessageQueue.js:366:47
<unknown>
MessageQueue.js:106:26
(etc...)

To Reproduce

I think the use of the CameraRoll library causes the issue. Issue started appearing after an upgrade from React Native 0.57.8 -> 0.58.6.

Expected Behavior

No warning produced.

Code Example

I haven’t been able to reproduce in an expo snack. But in a fresh project, I’ve been able to reproduce it. It requires you to manually link RNCameraRoll to the project in XCode, at which point it will generate a warning, regardless of using the library. Code example (does not produce error in Expo because it isn’t linked): https://snack.expo.io/@scarlac/rctimagepickermanager-error

Screenshot attached.

Environment

⚡️ react-native info

  React Native Environment Info:
    System:
      OS: macOS 10.14.3
      CPU: (12) x64 Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
      Memory: 1.98 GB / 32.00 GB
      Shell: 3.2.57 - /bin/bash
    Binaries:
      Node: 11.2.0 - ~/.nvm/versions/node/v11.2.0/bin/node
      Yarn: 1.13.0 - /usr/local/bin/yarn
      npm: 6.4.1 - ~/.nvm/versions/node/v11.2.0/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
      Android SDK:
        API Levels: 23, 25, 26, 27, 28
        Build Tools: 27.0.3, 28.0.2, 28.0.3
        System Images: android-27 | Intel x86 Atom_64, android-27 | Google APIs Intel x86 Atom, android-28 | Intel x86 Atom_64, android-28 | Google APIs Intel x86 Atom_64
    IDEs:
      Android Studio: 3.2 AI-181.5540.7.32.5056338
      Xcode: 10.1/10B61 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.6.3 => 16.6.3 
      react-native: 0.58.6 => 0.58.6 
    npmGlobalPackages:
      react-native-cli: 2.0.1

I looked into the source code and it seems that CameraRoll native modules indeed implement init but does not specify requiresMainQueueSetup. Check out Libraries/CameraRoll/RCTImagePickerManager.m to see.

[LuongTruong]

You can add this code in RCTImagePickerManager.m

- (id)init
{
  if (self = [super init]) {
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(cameraChanged:)
                                                 name:@"AVCaptureDeviceDidStartRunningNotification"
                                               object:nil];
  }
  return self;
}

// Please add this one
+ (BOOL)requiresMainQueueSetup
{
  return NO;
}

The warning will go away

[LuongTruong]

react native 0.59 still has this warning 😄