3rd party libraries with Swift break, because React-RCTFabric, React-Codegen, RCT-Folly, ... do not define modules

[mateusz1913]

I recently tried to play with creating a simple POC library, that is compatible with "New Architecture", and uses Swift on the iOS side, in order to learn how to migrate my library react-native-avoid-softinput.

When I added Swift files (inside the library directory) and made Pods synchronization in the example project, it failed with:

[!] The following Swift pods cannot yet be integrated as static libraries:

The Swift pod `poc-library` depends upon `React-RCTFabric`, `React-Codegen`, `RCT-Folly`, `RCTTypeSafety`, and `ReactCommon`, which do not define modules. To opt into those targets generating module maps (which is necessary to import them from Swift when building as static libraries), you may set `use_modular_headers!` globally in your Podfile, or specify `:modular_headers => true` for particular dependencies.

I found that it was already highlighted by @mrousavy in Playbook PR.

This is a blocker for migration of react-native-avoid-softinput and other libraries that are written in Swift.

Is there some roadmap for support of Swift libraries with "New Architecture" those pods (RCT-Folly, ReactCommon, etc.) to be compatible with Swift code?

[sammy-SC]

Hello @mateusz1913,

The new architecture is written in C++ and for React Native to support Swift out of the box, Swift needs to work with C++. At this moment, C++ interoperability is an ongoing effort within Swift project. There seems to be a lot of interest in the space and Swift has been making progress towards the interoperability. When Swift can work with C++, it should be possible to build native components in Swift as the new architecture's API are in C++.

For now, you should be able to wrap your Swift component in Obj-C++ native component. It is an extra step where C++ APIs will need to be manually transformed to Swift, but it should work.

[mateusz1913]

Hi @sammy-SC , thx for your response, but this is not what I actually meant to ask for. I am aware of Swift-C++ interoperability status. The problem is different

• libs depending on "New Architecture" Pods (e.g. React-RCTFabric, RCT-Folly) break during pod install, because those pods are not compatible with Swift code ([!] The following Swift pods cannot yet be integrated as static libraries)

I will change title and update description, to highlight react pods being incompatible and not C++ with Swift

[mateusz1913]

It will probably be resolved with facebook/react-native@709a459

I will mention it in 0.68 & 0.69 releases discussions