removal of RCTCxxBridge - internal method equivalents

[castdrian]

so basically, I'm not super well versed with the internals of react native, I understand a decent amount of what's going on with the deprecation of the legacy arch, however, I'm not super clear on a few things in partiular, namely a few projects I'm part of, - currently - depend on the fact that RCTCxxBridge is present inside a react native application, now that application is still using the old arch on iOS and we don't know when it'll be migrated, therefore the concern to future proof came up, and I was looking to acquire some sort of equivalent to the bridge methods that concern us, namely

- executeApplicationScript
- registerAdditionalModuleClasses

the crux of it is that we're on the lookout for basically equivalent functionality within the ecosystem of the new architecture

[cortinico]

depend on the fact that RCTCxxBridge is present inside a react native application, now that application is still using the old arch on iOS and we don't know when it'll be migrated, therefore the concern to future proof came up, and I was looking to acquire some sort of equivalent to the bridge methods that concern us, namely

We do have a dedicated RFC that talks about the future of those APIs:
react-native-community/discussions-and-proposals#929

tl;dr: you need to migrate to New Arch at some point.

I think it would be helpful to understand what are you using those 2 methods for, as there are probably equivalents already in the ecosystem

[castdrian]

We do have a dedicated RFC that talks about the future of those APIs: react-native-community/discussions-and-proposals#929

I've seen the rfc but I from what I got it's mostly tailored to people who use rn directly rather than interface with it externally hence I figured I'd ask directly

tl;dr: you need to migrate to New Arch at some point.

we're just an extension for the app so we don't have control over when that migration happens therefore the mentioned topic of future proofing came up since the android build is already on new arch, we expect the ios build to follow sometime soon whenever the used rn version is bumped up from the currently used 0.78

I think it would be helpful to understand what are you using those 2 methods for, as there are probably equivalents already in the ecosystem

we use those methods to inject an hbc/javascript extension and also a native module at runtime which lets extension developers use objc apis in addition to the already present js environment

https://github.com/unbound-app/loader-ios/blob/main/sources/Unbound.x#L1-L183

so the removal of the bridge eliminates both the entrypoint for the extension itself as well as the objc module registration, so yeah since everything is OSS I figured it'd make more sense to place a direct inquiry towards people who work with the codebase rather than going through all the changes on our own

[cortinico]

cc @cipolleschi as those are iOS methods

[cipolleschi]

@castdrian I would need to learn more about your use cases.

- executeApplicationScript

What are you doing here? why do you need to executeApplicationScript?

I think that this is not something we want to support, as it might be really unsafe for the application to be able to run arbitrary scripts. But we need to understand better your use case first.

- registerAdditionalModuleClasses

This can be easily answered by the Codegen configuration or by the ReactNativeFactoryDelegate that conforms to RCTTurboModuleManagerDelegate. You can implement the getModuleClassFromName in your ReactNativeFactoryDelegate and have it return the additional TurboModule that you need.

[castdrian]

@castdrian I would need to learn more about your use cases.

- executeApplicationScript

What are you doing here? why do you need to executeApplicationScript?

I think that this is not something we want to support, as it might be really unsafe for the application to be able to run arbitrary scripts. But we need to understand better your use case first.

- registerAdditionalModuleClasses

This can be easily answered by the Codegen configuration or by the ReactNativeFactoryDelegate that conforms to RCTTurboModuleManagerDelegate. You can implement the getModuleClassFromName in your ReactNativeFactoryDelegate and have it return the additional TurboModule that you need.

firstly, thanks, I reckon we can hook the delegate and return the class we want there probably, will need some tinkering, if you have any direct pointers on how to include a turbomodule as dylib that'd be great, as for applicationscript, as mentioned and linked above we inject an hbc or js bundle (based on hbc version compat) that is the client extension at runtime, whilst I reckon we can hook the jsi runtime and allat I figured it would be easier to just ask what exactly the direct equivalent here would be since scouring the truly gigantic codebase is a bit of an undertaking

edit: I've pretty much figured it out on my own (https://github.com/castdrian/RNiOSNewArchTweak) just use the jsi runtime to repare and execute the hbc bundle/eval the js bundle, and for native interop instead of dealing with the module stuff it's much easier to just install a global host function, so much cleaner than tweaking old arch apps tbh, good job lads