Build fails due to header files missing when using -fcxx-modules flag (AppDelegate.mm)

[uloco]

Description

I can't build the iOS project, always get the error /ios/Pods/Headers/Public/Yoga/yoga/YGNode.h:14:10: 'BitUtils.h' file not found. I tried cleaning up everything, reinstalling pods with repo update etc. etc., didn't work...

Version

0.68.1

Output of npx react-native info

info Fetching system and libraries information...
System:
OS: macOS 12.3.1
CPU: (8) arm64 Apple M1
Memory: 146.02 MB / 16.00 GB
Shell: 5.8 - /bin/zsh
Binaries:
Node: 16.13.0 - ~/Library/Caches/fnm_multishells/10309_1650316313370/bin/node
Yarn: 1.22.15 - ~/Library/Caches/fnm_multishells/10309_1650316313370/bin/yarn
npm: 8.7.0 - ~/Library/Caches/fnm_multishells/10309_1650316313370/bin/npm
Watchman: 2022.03.21.00 - /opt/homebrew/bin/watchman
Managers:
CocoaPods: 1.11.3 - /opt/homebrew/bin/pod
SDKs:
iOS SDK:
Platforms: DriverKit 21.4, iOS 15.4, macOS 12.3, tvOS 15.4, watchOS 8.5
Android SDK: Not Found
IDEs:
Android Studio: 2021.1 AI-211.7628.21.2111.8193401
Xcode: 13.3.1/13E500a - /usr/bin/xcodebuild
Languages:
Java: 11.0.14.1 - /usr/bin/javac
npmPackages:
@react-native-community/cli: Not Found
react: 17.0.2 => 17.0.2
react-native: 0.68.1 => 0.68.1
react-native-macos: Not Found
npmGlobalPackages:
react-native: Not Found

Steps to reproduce

I was currently upgrading from 0.66.3 to 0.68.1 and did all the steps in the upgrade helper to do so.
Afterwards the build is not working.

Snack, code example, screenshot, or link to a repository

[uloco]

I found out this only happens when the -fcxx-modules flag is set in OTHER_CPLUSPLUS_FLAGS. But I need this setting to be enabled because we are using react-native-nordic-dfu which uses @import syntax to import Swift modules. Is there any way to fix this without disabling the flag from a react-native side?

[uloco]

Is this maybe related to cocoapods not correctly linking all the cplusplus related files?

[cortinico]

because we are using react-native-nordic-dfu which uses @import syntax to import Swift modules

Have you considered raising this issue on react-native-nordic-dfu? I suppose they might have other users with this same problem

[uloco]

I will raise an issue there also, but i think this is a general problem. Is it in general not recommended to use this flag in react-native?

[uloco]

When I look into the header files the first one that can't be find is the BitUtils.h file. But the weird thing is, that it is present in the node_modules folder of react-native (ReactCommon...). This BitUtils.h file is referenced from the yoga package. There is a #ifdef __cplusplus in the YGNode.h file in which it trys to load the BitUtils.h. The files are just not in the pods/headers where they should be linked to. Is there maybe a cocoapods setting, which will link the correct cplusplus packages, when this flag is enabled?

[uloco]

FYI I managed to get the build working again by removing all cpp flags and renaming AppDelegate.mm back to AppDelegate.m. I guess this will break other things in the future (maybe the new arch) but at least I can work with this now.

[cortinico]

I guess this will break other things in the future (maybe the new arch) but at least I can work with this now.

Yup that's correct, you won't be able to use the New Architecture with .m

[jkadamczyk]

Hey! Not much help there but, I also have this issue with a different library. I tried adding -fcxx-modules flag and yoga was broken as well in the same file.
The library in question is quite popular one – Segment Analytics.
I was trying to call Segment Track in AppDelegate.mm I think it would fail if I tried to initialise it as well since it depends on the same Header file.

[uloco]

The weird thing is, the missing files are actually inside the node_modules folder but not in the Pods/Headers folder. The headers that are specified in the yoga ifdef __cplusplus part are not linked there correctly. This seems more like a cocoapods issue, doesn't it?