Firebase Undefined symbols for architecture x86_64

Question

I am using firebase as part of a project I am working on in iOS, and I just stumbled upon the following linking error when I try to compile my code against an iPhone 6 or 7

Answer 1

I tried the "clearing Cocoapods cache" and the "removing derived data" solutions but that didn't work. What worked for me was a step I found in the Carthage setup (I'm still using Cocoapods)

Add $(OTHER_LDFLAGS) -ObjC flag to "Other Linker Flags" in "Build Settings".

You can see the step here: https://github.com/firebase/firebase-ios-sdk/blob/master/Carthage.md

My Info

Installation: Cocoapods | SDK: FirebaseAnalytics (6.1.2) | IDE: Xcode 11.0 | macOS: Mojave 10.14.5 Beta | Language: Swift 4.2 | Platform Target: iOS 11.0+