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

Also had this problem after installing pods for Firebase, using CocoaPods as explained in the Firebase site:

https://firebase.google.com/docs/ios/setup?hl=es-419#prerequisites

pod 'Firebase/Analytics' pod 'Firebase/Auth'

During the installation of the pods I received a warning telling that:

[!] The target `myTarget [Debug]` overrides the `OTHER_LDFLAGS` build setting defined in `Pods/Pods.xcconfig'.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.

[!] The target `myTarget [Release]` overrides the `OTHER_LDFLAGS` build setting defined in `Pods/Pods.xcconfig'.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.

When I compiled I got the error for several files:

Undefined symbols for architecture x86_64:

I tried the solution of the following answer before the one in this answer, and it worked as a charm:

The target ... overrides the `OTHER_LDFLAGS` build setting defined in `Pods/Pods.xcconfig

Basically the solution was (as explained by @Ankish Jain):

Go to your Target Build Settings -> Other linker flags -> double click -> + button. Add $(inherited) to a new line.

After that I compiled succesfully, and new flag where added automatically to the Build Settings.

Answer 2

In my case everything worked after removing $(inherited) from Other Linker Flags

Answer 3

Check your Other linker flags: sometimes adding or removing $(inherited) solves the issue.

Answer 4

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+

Answer 5

It seems to be a glitch with derived data. I quitted out of Xcode, I removed all Derived Data in /Users/USER_NAME/Library/Developer/Xcode/PROJECT_NAME

Restarted Xcode, compiled and all works as expected, no need to change anything in Active Architecture Only or anything.