iOS: Undefined symbols for architecture x86_64/arm64

[WNemencha]

Hello, DataDog team! :)

Describe what happened:
When trying to compile our app for iOS (react-native app), with freshly yarn added dd-sdk-reactnative, it fails with the following error:

Undefined symbols for architecture x86_64:
  "static Foundation.JSONEncoder.OutputFormatting.withoutEscapingSlashes.getter : Foundation.JSONEncoder.OutputFormatting", referenced from:
      static (extension in Datadog):Foundation.JSONEncoder.default() -> Foundation.JSONEncoder in libDatadogSDK.a(JSONEncoder.o)
  "Network.NWPath.isConstrained.getter : Swift.Bool", referenced from:
      closure #2 () -> Swift.Bool? in closure #1 (Network.NWPath) -> () in Datadog.NWPathNetworkConnectionInfoProvider.init(monitor: Network.NWPathMonitor) -> Datadog.NWPathNetworkConnectionInfoProvider in libDatadogSDK.a(NetworkConnectionInfoProvider.o)
  "(extension in Foundation):__C.NSFileHandle.readToEnd() throws -> Foundation.Data?", referenced from:
      Datadog.File.read() throws -> Foundation.Data in libDatadogSDK.a(File.o)
  "(extension in Foundation):__C.NSFileHandle.seekToEnd() throws -> Swift.UInt64", referenced from:
      Datadog.File.append(data: Foundation.Data) throws -> () in libDatadogSDK.a(File.o)
  "(extension in Foundation):__C.NSFileHandle.write<A where A: Foundation.DataProtocol>(contentsOf: A) throws -> ()", referenced from:
      Datadog.File.append(data: Foundation.Data) throws -> () in libDatadogSDK.a(File.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Steps to reproduce the issue:

1. Install dd-sdk-reactnative in a react-native v0.63.4 project (ios/android)
2. cd ios/ && pod install
3. react-native run-ios

Describe what you expected:

I expected the build to succeed, as the one for Android does.

Additional context:

• "dd-sdk-reactnative": "^1.0.0-alpha5",

[0xnm]

Hello @WNemencha! Can you please check if the same happens if you try to build our sample app on your machine? Also can you please tell which XCode version you are using?

[WNemencha]

Hey @0xnm,

I've just tried to run your sample app and it seems to be compiling and running but I still can't receive any log inside my test DataDog account (in the RUM apps section).

I've been trying to fix this issue since yesterday and now that I think about it, it looks more like a Swift error to me, currently investigating ;). About XCode: Version 12.4 (12D4e)

[buranmert]

hi @WNemencha 👋
thanks for reporting the issue!
the issue seems to be caused by a fix in React Native.
we raised react/react-native#31417 to fix this in React Native template but this may take time.

Problem

Swift frameworks can't be linked statically in pure Obj-C projects. React Native was keeping an empty Swift.swift file in its template project as a workaround, that makes it a Swift&Obj-C mixed target so that it works. the fix i mentioned above removed this file and set custom Library Search Paths for the compiler to find required Swift symbols during linking. however, it seems to be set to a wrong location and can't find some of the Swift symbols that our SDK relies on.

Fix

please check that Library Search Paths in your {MyApp} project points to the following

LIBRARY_SEARCH_PATHS = (
  "\"$(TOOLCHAIN_DIR)/usr/lib/swift/$(PLATFORM_NAME)\"",
  "\"$(TOOLCHAIN_DIR)/usr/lib/swift-5.0/$(PLATFORM_NAME)\"",
  "\"$(inherited)\"",
);

if so, can you please replace $(TOOLCHAIN_DIR)/usr/lib/swift-5.0/$(PLATFORM_NAME) with /usr/lib/swift/ as seen in the screenshot below?

let me know if that works (or not!) for you and/or if you have any other questions

[WNemencha]

You know what ? It works! Thanks dear @buranmert, you saved the sprint :)

[buranmert]

@WNemencha good news 👍
i'm closing the issue as the issue is solved

[papaschmidt]

I have been getting the exact same issue. While it will build after making the change listed in this issue, the app just closes out immediately afterwards when you attempt to load it.

'/usr/local/lib/libswiftCore.dylib' (no such file), '/usr/lib/libswiftCore.dylib' (no such file) from the Output

I've tried going to Build Settings in the target and changing Always Embed Swift Standard Libraries to Yes, but that doesn't seem to help here. Any ideas what I need to do to get this working?

[buranmert]

hi @papaschmidt

i guess Always Embed Swift Standard Libraries shouldn't be needed as Swift libraries should already exist in iOS system images.

can you tell me which React Native, Xcode and iOS version you are using?
does your project contain Swift code as well?
has it ever worked before (e.g: with an older Datadog SDK or Xcode version) ?

[papaschmidt]

Hello @buranmert ,

I am on the following:

react-native: 0.64.2
Xcode: Version 13.1 (13A1030d)
iOS: I am doing testing on 15.

We don't have any custom swift code that we wrote in this code base, however, some of our 3rd party libraries might have swift code.

This is our first attempt at integrating DataDog SDK into our project as we're looking to add it to our app for logging, so I haven't gotten it to work yet. I did have to add a USER_DEFINED property SWIFT_VERSION to 5.0 to get it to install the pods, but I'm not sure if that is relevant to this.

[sregg]

I thought this solution #41 (comment) for me didn't work until I realized I was looking at my Target's Build Settings and not my App's.
Thought I'd share that if others make the same mistake.