Duplicate symbols when integrating Firebase and Google Sign In SDKs manually without Cocoapods

Question

I am getting duplicate symbols error when integrating Firebase and Google Sign In SDKs manually in my existing iOS project.

The related SO question here didn't help as it uses Cocoapods.

Firebase and Google Signin giving duplicate symbols error

Steps I have taken in chronological order:

1. Copied Analytics, Auth and Database folder along with Firebase.h file from the downloaded Firebase SDK (3.11.0) into my project and added to targets.

2. Copied the GoogleService-Info.plist into the project and added to targets.

3. Added the -ObjC flag to other linker flags.

4. Copied the necessary frameworks and bundles from the downloaded Google Sign In SDK (4.0.1) into my project and added to targets.

5. Linked the necessary frameworks and libraries.

Here is the related project structure:

Firebase     Analytics         FirebaseAnalytics.framework         FirebaseCore.framework         FirebaseInstanceId.framework         GoogleInterchangeUtilities.framework         GoogleSymbolUtilities.framework         GoogleToolboxForMac.framework     Auth         FirebaseAuth.framework         GTMSessionFetcher.framework GoogleSignIn     GoogleAppUtilities.framework     GoogleSignIn.bundle     GoogleSignIn.framework     GoogleSignInDependencies.framework     GoogleSymbolUtilities.framework (removed as Firebase Analytics already includes it) 

Here is the error log (truncated):

Ld /Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Products/Debug-iphonesimulator/AddressBookGoogleMaps.app/AddressBookGoogleMaps normal x86_64     cd /Projects/iOS/AddressBookGoogleMaps     export IPHONEOS_DEPLOYMENT_TARGET=8.0     export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin"     /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator10.2.sdk -L/Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Products/Debug-iphonesimulator -F/Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Products/Debug-iphonesimulator -F/Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics -F/Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth -F/Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Database -F/Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn -filelist /Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Intermediates/AddressBookGoogleMaps.build/Debug-iphonesimulator/AddressBookGoogleMaps.build/Objects-normal/x86_64/AddressBookGoogleMaps.LinkFileList -Xlinker -rpath -Xlinker @executable_path/Frameworks -mios-simulator-version-min=8.0 -dead_strip -Xlinker -object_path_lto -Xlinker /Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Intermediates/AddressBookGoogleMaps.build/Debug-iphonesimulator/AddressBookGoogleMaps.build/Objects-normal/x86_64/AddressBookGoogleMaps_lto.o -Xlinker -export_dynamic -Xlinker -no_deduplicate -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -ObjC -Xlinker -sectcreate -Xlinker __TEXT -Xlinker __entitlements -Xlinker /Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Intermediates/AddressBookGoogleMaps.build/Debug-iphonesimulator/AddressBookGoogleMaps.build/AddressBookGoogleMaps.app.xcent -framework GoogleToolboxForMac -framework FirebaseAuth -framework FirebaseAnalytics -framework GoogleSignInDependencies -framework SystemConfiguration -framework GoogleAppUtilities -framework GTMSessionFetcher -framework FirebaseCore -framework GoogleSignIn -framework SafariServices -framework GoogleSymbolUtilities -framework Accelerate -framework GoogleSymbolUtilities -framework GoogleInterchangeUtilities -framework FirebaseDatabase -framework FirebaseInstanceID -Xlinker -dependency_info -Xlinker /Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Intermediates/AddressBookGoogleMaps.build/Debug-iphonesimulator/AddressBookGoogleMaps.build/Objects-normal/x86_64/AddressBookGoogleMaps_dependency_info.dat -o /Users/Ehtesham/Library/Developer/Xcode/DerivedData/AddressBookGoogleMaps-hbtfxxvykazaogbfqnnraeuywtdt/Build/Products/Debug-iphonesimulator/AddressBookGoogleMaps.app/AddressBookGoogleMaps  duplicate symbol _OBJC_CLASS_$_GTMLogStandardFormatter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_METACLASS_$_GTMLogStandardFormatter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_CLASS_$_GTMLogBasicFormatter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_METACLASS_$_GTMLogBasicFormatter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_CLASS_$_GTMLogNoFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_METACLASS_$_GTMLogNoFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_CLASS_$_GTMLogMininumLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_METACLASS_$_GTMLogMininumLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_CLASS_$_GTMLogMaximumLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_METACLASS_$_GTMLogMaximumLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_CLASS_$_GTMLogLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_METACLASS_$_GTMLogLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o) duplicate symbol _OBJC_CLASS_$_GTMLogAllowedLevelFilter in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Analytics/GoogleToolboxForMac.framework/GoogleToolboxForMac(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMLogger_e66760ac68814bab22c3e6b0850da5e6.o)  ........................................ ........................................  duplicate symbol _OBJC_IVAR_$_GTMSessionFetcherService._cookieStorageMethod in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionFetcherService_c6b7326897506dd1305d6961fdc1ec8b.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionFetcherService_c6b7326897506dd1305d6961fdc1ec8b.o) duplicate symbol _OBJC_IVAR_$_GTMSessionFetcherService._retryEnabled in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionFetcherService_c6b7326897506dd1305d6961fdc1ec8b.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionFetcherService_c6b7326897506dd1305d6961fdc1ec8b.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadGranularity in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._shouldInitiateOffsetQuery in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._lastChunkRequest in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._initialBodySent in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._fetcherInFlight in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._currentOffset in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._useBackgroundSessionOnChunkFetchers in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._recentChunkReponseHeaders in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._delegateCompletionHandler in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._chunkFetcher in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_CLASS_$_GTMSessionUploadFetcher in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_METACLASS_$_GTMSessionUploadFetcher in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadDataProvider in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _kGTMSessionFetcherUploadLocationObtainedNotification in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._initialBodyLength in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadFileLength in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._subdataGenerating in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._isSubdataGenerating in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _kGTMSessionUploadFetcherMaximumDemandBufferSize in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._chunkSize in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _kGTMSessionUploadFetcherStandardChunkSize in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._delegateCallbackQueue in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadMIMEType in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadFileHandle in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._recentChunkStatusCode in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._isPaused in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._isRestartedUpload in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadData in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadLocationURL in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) duplicate symbol _OBJC_IVAR_$_GTMSessionUploadFetcher._uploadFileURL in:     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/GoogleSignIn/GoogleSignInDependencies.framework/GoogleSignInDependencies(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o)     /Projects/iOS/AddressBookGoogleMaps/AddressBookGoogleMaps/Sources/Externals/Firebase/Auth/GTMSessionFetcher.framework/GTMSessionFetcher(GTMSessionUploadFetcher_fb894b20da0d1114d3ddd8f56ed741c5.o) ld: 194 duplicate symbols for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) 

Answer 1

This is how I solved it although it is far from the ideal solution.

(This solution can be applied to any case where two static libraries cause "duplicate symbol" error due to both libraries containing common classes and using -ObjC or -all_load flag.)

Copy the GoogleSignInDependencies file inside the GoogleSignInDependencies.framework in a separate location PATH. This file is a fat file meaning it has codes for different architectures.

Open the terminal and go to PATH.

$ cd PATH 

Run the command following command to get info about the fat library.

$ lipo -info GoogleSignInDependencies 

You will get the following result.

Architectures in the fat file: GoogleSignInDependencies are: armv7 i386 x86_64 arm64 

As you can see there are 4 architectures in the fat file.

Get the thin files (file that contains code for only one architecture) from the fat file by running the following commands.

$ lipo -thin armv7 GoogleSignInDependencies -output armv7.a $ lipo -thin i386 GoogleSignInDependencies -output i386.a $ lipo -thin x86_64 GoogleSignInDependencies -output x86_64.a $ lipo -thin arm64 GoogleSignInDependencies -output arm64.a 

You will get 4 thin files named armv7.a, i386.a, x86_64.a and arm64.a.

Delete the GoogleSignInDependencies file, we don't need it anymore.

Create 4 new folders named armv7, i386, x86_64 and arm64. Then move the thin files armv7.a, i386.a, x86_64.a and arm64.a to the respective folders. You should have a folder structure like the following.

arm64     arm64.a armv7     armv7.a i386     i386.a x86_64     x86_64.a 

Go to each of the 4 folders from terminal and extract the object files (*.o) from the thin files using the following commands.

$ cd armv7 $ ar -x armv7.a $ cd ../i386 $ ar -x i386.a $ cd ../x86_64 $ ar -x x86_64.a $ cd ../arm64 $ ar -x arm64.a 

After running these commands each of the 4 folders should contain the following files. (This can change in future versions.)

__.SYMDEF GTMGeometryUtils_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMLogger_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMNSDictionary+URLArguments_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMNSString+URLArguments_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMOAuth2Authentication_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMOAuth2SignIn_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMOAuth2ViewControllerTouch_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionFetcher_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionFetcherLogging_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionFetcherService_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionUploadFetcher_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSynchronizationAsserts_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o 

Delete the files that are conflicting with the Firebase library from each of the 4 folders. You need to delete these 6 files. (This can change in future versions.)

GTMLogger_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMNSDictionary+URLArguments_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionFetcher_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionFetcherLogging_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionFetcherService_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o GTMSessionUploadFetcher_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.o 

Delete the thin files armv7.a, i386.a, x86_64.a and arm64.a.

Combine the remaining object files into thin files by running the following commands.

$ cd armv7 $ libtool -static *.o -o armv7-new.a $ cd ../i386 $ libtool -static *.o -o i386-new.a $ cd ../x86_64 $ libtool -static *.o -o x86_64-new.a $ cd ../arm64 $ libtool -static *.o -o arm64-new.a 

Copy the newly created thin files armv7-new.a, i386-new.a, x86_64-new.a and arm64-new.a to a new location PATH_NEW. You can delete everything else inside PATH.

Combine the new thin files into a new fat file by running the following commands.

$ cd PATH_NEW $ lipo -create armv7-new.a i386-new.a x86_64-new.a arm64-new.a -output GoogleSignInDependencies-new 

Use the newly generated GoogleSignInDependencies-new in place of GoogleSignInDependencies in your Xcode project.

I strongly recommend the following article for deeper understanding of the things.

http://atnan.com/blog/2012/01/12/avoiding-duplicate-symbol-errors-during-linking-by-removing-classes-from-static-libraries