After update from 0.74.5 to 0.76.6, my App is still running Paper on iOS. Android works fine with Fabric

[ric-sanchez-salesloft]

Been dealing with this issue for a couple of weeks and I'm going crazy!!

After updating my App to 0.76.6 following the guide on Upgrade Helper, my app started almost immediately in Android, YEY!

However, after running RCT_NEW_ARCH_ENABLED=1 bundle exec pod install, the iOs App still runs on Paper renderer, and many of the Native modules fails to loading, and thus, the app is not working...

How I know Android is working with Fabric and iOs not?

Added this on my App.tsx entry point file

  const uiManager = global?.nativeFabricUIManager ? 'Fabric' : 'Paper'
  console.log(`Using ${uiManager} on ${isIOS() ? 'ios' : 'android'}`)

iOs output:

LOG Running "MySadApp" with {"rootTag":1,"initialProps":{}}
Using Paper on ios

Android output:

(NOBRIDGE) LOG Running "MySadApp" with {"rootTag":21,"initialProps":{},"fabric":true}
Using Fabric on android

As you can see, the differences are the NOBRIDGE directive on log entry, and that sweet "fabric":true on Android output.

I cannot provide a reproduction repo, as this is a company private repo :(

Looking for some advices on how to begin debugging my iOS app, or any experience you can share with me about your upgrade process to new Architecture

Thanks a lot for reading this.

Additional data:

npx react-native info

System:
  OS: macOS 14.3
  CPU: (12) arm64 Apple M2 Pro
  Memory: 2.25 GB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 18.18.0
    path: ~/.asdf/installs/nodejs/18.18.0/bin/node
  Yarn: Not Found
  npm:
    version: 9.8.1
    path: ~/.asdf/plugins/nodejs/shims/npm
  Watchman:
    version: 2024.12.02.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /Users/my_name/.asdf/shims/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.5
      - iOS 17.5
      - macOS 14.5
      - tvOS 17.5
      - visionOS 1.2
      - watchOS 10.5
  Android SDK:
    API Levels:
      - "28"
      - "31"
      - "33"
      - "34"
      - "35"
    Build Tools:
      - 30.0.3
      - 31.0.0
      - 33.0.0
      - 33.0.1
      - 33.0.2
      - 34.0.0
      - 34.0.0
      - 34.0.0
      - 34.0.0
      - 35.0.0
      - 35.0.0
    System Images:
      - android-33 | Google APIs ARM 64 v8a
      - android-33 | Google Play ARM 64 v8a
      - android-34 | Google APIs ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2024.2 AI-242.23726.103.2422.12816248
  Xcode:
    version: 15.4/15F31d
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.13
    path: /opt/homebrew/opt/openjdk@17/bin/javac
  Ruby:
    version: 2.7.6
    path: /Users/my_name/.asdf/shims/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.1.3
    wanted: ^15.0.0
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.76.6
    wanted: ^0.76.0
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

[cortinico]

As you can see, the differences are the NOBRIDGE directive on log entry, and that sweet "fabric":true on Android output.

That's a good indicator on whether you're running NewArch or not.

I suspect there is something going on in your AppDelegate file, but without seeing it, is really hard to give you any support. Perhaps @cipolleschi can help you further here?

Also have you tried to diff your AppDelegate file with the one from the template: https://github.com/react-native-community/template/tree/0.76-stable/template/ios/HelloWorld

[cipolleschi]

My best guess is that someone has hardcoded an RCT_NEW_ARCH_ENABLED=0 somewhere in your Podfile/ruby scripts, @ric-sanchez-salesloft.

One thing you can check is to open the project in Xcode and add a breakpoint at this line and at this line and see what get executed.
You can also force the New Architecture by override the newArchEnabled method in the AppDelegate and make it return true.

Another way to investigate is adding some puts <message> in the Cocoapods infrastructure and see what's happening there.
The entry point is here and it will be in node_modules/react-native/scripts/react_native_pods.rb.

Without a reproducer I can't help further, but I hope that these pointers can help.