Firebase auth crashes the app with: [GTMSessionFetcher setFetcher:forTask:]: unrecognized selector sent to instance

[eyalevy]

Describe your environment

• Xcode version: 10.1
• Firebase SDK version: 5.15.0
• Firebase Component: Auth
• Component version: 5.15.0

Describe the problem

the app crashes when using signInWithCustomToken. the error log is: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[GTMSessionFetcher setFetcher:forTask:]: unrecognized selector sent to instance.
It seems there is a collision beetween firebase sdk and Trustkit (https://github.com/datatheorem/TrustKit).

Steps to reproduce:

Run the example app in this repository (react native, although it does not seem related...):
https://github.com/eyalevy/trustkit-firebase-sample

[morganchen12]

This looks similar to crashes that can be caused by missing linker flags. Can you share the stack trace of the crash?

[eyalevy]

This is my linker flags: https://github.com/eyalevy/trustkit-firebase-sample/blob/e048d3d4ae630b3e97c814bcf2b1c42449d3a85d/ios/trustkitfirebasesample.xcodeproj/project.pbxproj#L1228
Am I missing something?

Also this is the stack trace:

(
	0   CoreFoundation                      0x000000010bd971bb __exceptionPreprocess + 331
	1   libobjc.A.dylib                     0x0000000109dc3735 objc_exception_throw + 48
	2   CoreFoundation                      0x000000010bdb5f44 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
	3   CoreFoundation                      0x000000010bd9bed6 ___forwarding___ + 1446
	4   CoreFoundation                      0x000000010bd9dda8 _CF_forwarding_prep_0 + 120
	5   trustkitfirebasesample              0x0000000107536372 -[GTMSessionFetcherService fetcherDidBeginFetching:] + 402
	6   trustkitfirebasesample              0x000000010751102b -[GTMSessionFetcher beginFetchMayDelay:mayAuthorize:] + 11099
	7   trustkitfirebasesample              0x000000010750d419 -[GTMSessionFetcher beginFetchWithCompletionHandler:] + 329
	8   trustkitfirebasesample              0x00000001073ec14f -[FIRAuthBackendRPCIssuerImplementation asyncPostToURLWithRequestConfiguration:URL:body:contentType:completionHandler:] + 1023
	9   trustkitfirebasesample              0x00000001073ef9ff -[FIRAuthBackendRPCImplementation postWithRequest:response:callback:] + 1087
	10  trustkitfirebasesample              0x00000001073ed33b -[FIRAuthBackendRPCImplementation verifyCustomToken:callback:] + 299
	11  trustkitfirebasesample              0x00000001073eb34b +[FIRAuthBackend verifyCustomToken:callback:] + 123
	12  trustkitfirebasesample              0x00000001073df93e -[FIRAuth internalSignInAndRetrieveDataWithCustomToken:completion:] + 286
	13  trustkitfirebasesample              0x00000001073d7c97 __44-[FIRAuth signInWithCustomToken:completion:]_block_invoke + 183
	14  libdispatch.dylib                   0x000000010dfa6595 _dispatch_call_block_and_release + 12
	15  libdispatch.dylib                   0x000000010dfa7602 _dispatch_client_callout + 8
	16  libdispatch.dylib                   0x000000010dfaeb0b _dispatch_lane_serial_drain + 791
	17  libdispatch.dylib                   0x000000010dfaf784 _dispatch_lane_invoke + 428
	18  libdispatch.dylib                   0x000000010dfb989a _dispatch_workloop_worker_thread + 733
	19  libsystem_pthread.dylib             0x000000010e378fd2 _pthread_wqthread + 980
	20  libsystem_pthread.dylib             0x000000010e378be9 start_wqthread + 13
)

[morganchen12]

Linker flags look fine to me. @renkelvin can you take a look?

[renkelvin]

Hi all, I believe it's not an issue with the Auth SDK. GTMSessionFetcher is our main entry point talking to backend. All requests would fail if GTMSessionFetcher is not properly linked. Could you try other apis to see if it's the same issue?

[paulb777]

@eyalevy Please share the Podfile and Podfile.lock so we can check if there's something strange about the versions being used.

[eyalevy]

Sure, the links for Podfile and Podfile.lock:

• Podfile : https://github.com/eyalevy/trustkit-firebase-sample/blob/e048d3d4ae/ios/Podfile
• Podfile.lock - https://github.com/eyalevy/trustkit-firebase-sample/blob/e048d3d4ae/ios/Podfile.lock

I want to add that this issue happened when we upgrade Firebase SDK version from version 4.9 to version 5.15. when I downgrade Firebase SDK to version 4.9 the app is not crashing.

[eyalevy]

@renkelvin I tried to use firebase storage for getting a file and I succeed to read it.

[eyalevy]

@renkelvin @paulb777 did any of you experience this error?

[maksymmalyhin]

@eyalevy I wonder, if you can reproduce the crash if you remove pod 'TrustKit'. From the first glance, TrustKit does method swizzling on NSURLSessionDelegate which could be a reason of the issue.

If we know this we may narrow down the issue search area. Thanks.

[eyalevy]

@maksymmalyhin when I disable swizzling or remove TrustKit completely the issue doesn't reproduce.

I want to add that we did not add TrustKit recently. The last change we did is to upgrade Firebase SDK from version 4.9 to version 5.15. With Firebase SDK v4.9 and TrustKit the issue doesn't reproduce as well.

[maksymmalyhin]

@eyalevy Thank you for the quick response. We will investigate how we can fix it.

[maksymmalyhin]

It looks like there is an open PR to fix the issue google/gtm-session-fetcher#130

[paulb777]

It looks like the google/gtm-session-fetcher#130 creator stopped responding to the reviewer's questions months ago, so the discussion would need to be revived.