App Check no longer compiles as an Objective-C++ module as of 10.16.0

[mikehardy]

Per Paul B - this has already been noticed internally and is in progress, he mentioned I could open an issue for tracking and I'd like to do so

My original comment on the PR between firebase-ios-sdk 10.15.0 and 10.16.0 follows:

---

When I attempt to update react-native-firebase to firebase-ios-sdk 10.16.0, including this PR, I receive this:

❌ /Users/mike/work/invertase/react-native-firebase/tests/ios/build/Build/Products/Debug-iphonesimulator/FirebaseAppCheck/FirebaseAppCheck.framework/Headers/FIRAppCheck.h:19:1: use of '@import' when C++ modules are disabled, consider using -fmodules and -fcxx-modules
@import FirebaseAppCheckInterop;
^

I traced it to this PR when I noticed that header file changed in my pod cache between 10.15.0 and 10.16.0. Is this an expected outcome? (stated differently, is there something I need to change so this works, ideally that wouldn't be a breaking change for us since we're adopting a feature release here...)

It's coming from here:
https://github.com/invertase/react-native-firebase/blob/c9b695aa8fd75d5a1d070ecbb6bb9ac4e9ff062e/tests/ios/testing/AppDelegate.mm#L21
Which goes to here:
https://github.com/invertase/react-native-firebase/blob/c9b695aa8fd75d5a1d070ecbb6bb9ac4e9ff062e/packages/app-check/ios/RNFBAppCheck/RNFBAppCheckModule.h#L22
Which goes to here:
https://github.com/invertase/react-native-firebase/blob/c9b695aa8fd75d5a1d070ecbb6bb9ac4e9ff062e/packages/app-check/ios/RNFBAppCheck/RNFBAppCheckProviderFactory.h#L18

...and that file doesn't go through with our compiler settings 🤔

Is there anything that can be done here?

In issues past, I have attempted to provide build instructions for our test app over in react-native-firebase so reproductions are easy but I/we have observed you all may have difficulty since it requires a relatively up to date javascript / node environment etc etc and that's a time suck if you don't already have it running. Let me know if you want repro instructions or any other information though, happy to collaborate of course

Originally posted by @mikehardy in #11660 (comment)

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[mikehardy]

Just as a release note - this puts us in a little bit of a bind release-wise with a crash bug in Firestore from the gRPC library change making 10.16.0 a desirable update contrasted with an inability to recommend it as a general thing with an app check compile failure.

It does not appear possible to use podspec magic in our react-native-firebase podspec to alter the gRPC transitive dependency version from FirebaseFirestore.podspec, nor does it appear possible to override the gRPC pod version to 1.49.1 in an app's Podfile. If I am wrong in that I'd welcome the correction so we could provide guidance to fix firestore crashes

If I am right that there is no easy way to override the gRPC update in 10.15.0 firebase-ios-sdk release then it would be nice to see either a 10.15.1 that included just the gRPC change as a cherry-pick or to see a 10.16.1 (or 10.17.0 I suppose) that just had the compile fix so that either could come sooner. This may have all already been taken into account, but I mention it just in case. Cheers

[paulb777]

I'm not recommending this, but the right podspec magic might be to copy the FirebaseFirestore.podspec, change the grpc dependency, rename the podspec, publish it and depend on that pod from react-native.

[paulb777]

@mikehardy Is there a reason that react-native needs to integrate via Objective-C++ versus Objective-C? If not, using Objective C could be a workaround.

[mikehardy]

React-native is C++ now, they use code generators etc, all of which results in lots of C++ in the system so that's outside our ability to change I believe

[paulb777]

FYI, we plan to have a fix in the 10.17.0 release due out the week of October 23rd. We considered a patch, but determined the change is too far-ranging and should go through the full minor release cycle.