Amplify fetchAuthSession Crash

[aokj4ck]

Describe the bug

I'm receiving crash reports from Firebase that Amplify is crashing during app launch.

Steps To Reproduce

Steps to reproduce the behavior:
1. UIWindowSceneDelegate.scene(: willConnectTo: options:) invokes Amplify.add(plugin: AWSCognitoAuthPlugin()) and Amplify.configure() successfully.
2. Some time later UIApplicationDelegate.application(: didRegisterForRemoteNotificationsWithDeviceToken:) is called and through Combine and intermediate steps invokes Amplify.Auth.fetchAuthSession() to retrieve the AWSAuthCognitoSession and query the `cognitoTokensResult`
3. At some point in step 2 the crash occurs.

Expected behavior

Authentication and push token registration complete without crashing.

Amplify Framework Version

1.31.0

Amplify Categories

Auth

Dependency manager

Swift PM

Swift version

"Swift 5" in Xcode build settings corresponding to Swift 5.0

CLI version

12.14.4

Xcode version

16.2

Relevant log output

<details>
<summary>Log Messages</summary>

          Crashed: com.apple.main-thread
0  RedactedAppName                   0x276f78 AuthCategory.fetchAuthSession(options:listener:) + 99 (AuthCategory+ClientBehavior.swift:99)
1  RedactedAppName                   0x747e0 specialized Authentication.getTokens() + 272 (Authentication.swift:272)
2  RedactedAppName                   0x74128 protocol witness for AuthenticationProvider.getLatestToken() in conformance Authentication + 4376445224 (<compiler-generated>:4376445224)
3  RedactedAppName                   0x1f5394 Client.setUserPushToken(data:) + 65 (Client+Authentication.swift:65)
4  RedactedAppName                   0x49d20 specialized AppDelegate.application(_:didRegisterForRemoteNotificationsWithDeviceToken:) + 198 (AppDelegate.swift:198)
5  RedactedAppName                   0x4896c @objc AppDelegate.application(_:didRegisterForRemoteNotificationsWithDeviceToken:) + 4376267116 (<compiler-generated>:4376267116)
6  UIKitCore                      0x4bd18c __63-[UIApplication pushRegistry:didUpdatePushCredentials:forType:]_block_invoke + 96
7  libdispatch.dylib              0x2248 _dispatch_call_block_and_release + 32
8  libdispatch.dylib              0x3fa8 _dispatch_client_callout + 20
9  libdispatch.dylib              0x12a34 _dispatch_main_queue_drain + 984
10 libdispatch.dylib              0x1264c _dispatch_main_queue_callback_4CF + 44
11 CoreFoundation                 0x79bcc __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16
12 CoreFoundation                 0x761c0 __CFRunLoopRun + 1996
13 CoreFoundation                 0xc8284 CFRunLoopRunSpecific + 588
14 GraphicsServices               0x14c0 GSEventRunModal + 164
15 UIKitCore                      0x3ee674 -[UIApplication _run] + 816
16 UIKitCore                      0x14e88 UIApplicationMain + 340
17 RedactedAppName                   0x48c58 main + 21 (AppDelegate.swift:21)
18 ???                            0x1c316dde8 (Missing)

</details>

Is this a regression?

Yes

Regression additional context

No response

Platforms

iOS

OS Version

iOS 14 to iOS 18

Device

iPhone XS to iPhone 16, all models

Specific to simulators

No

Additional context

This is using a suite of Cognito and AWS lambdas to provide the rest of authentication. I wasn't able to open this issue without selecting a a value for "Amplify Categories". Is this a new requirement? I don't think my project is using any categories because it is a custom Cognito implementation.

This seems very similar to an earlier crash report, and the last suggestion there was to ensure that Amplify.add(plugin: AWSCognitoAuthPlugin()) is only called once. I tried invoking add(plugin:) twice (by duplicating the function call on the next line) but was not able to cause a crash. Link: #1639

This crash is affecting a subset of customers and I have not been able to reproduce it.

[harsh62]

@aokj4ck Can you provide the entire stack trace and also the setup code.

I suspect, you are calling fetchAuthSession before configuring Amplify, but you would have to provide the Amplify setup and usage.

[aokj4ck]

@harsh62 sure, this is the entire stack trace I've been able to get from Firebase Console. Here's a slightly simplified setup code. Crashes are split, almost evenly, between "signedIn" and "signedOut" user states.

Listing 1: Initialization

Listing 1: Initialization

extension AppCoordinator: UIWindowSceneDelegate {

    func scene(
        _ scene: UIScene,
        willConnectTo session: UISceneSession,
        options connectionOptions: UIScene.ConnectionOptions
    ) {

        guard let windowScene = scene as? UIWindowScene else {
            return
        }

        // ... redacted

        #if DEBUG
        Amplify.Logging.logLevel = .verbose
        #endif

        // Initialize the Amplify Auth category
        do {
            try Amplify.add(plugin: AWSCognitoAuthPlugin())
            try Amplify.configure()
            Logger.info("Amplify configured with auth plugin")
        } catch {
            Logger.error("Failed to initialize Amplify with \(error)")
        }

        let window = UIWindow(windowScene: windowScene)
        configure(window: window)
        self.window = window
        window.makeKeyAndVisible()

        // ... redacted
    }
}

Listing 2: Crash Site Invocation (entry point)

Listing 2: Crash site invocation (entry point)

class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        let apiClient = Container.shared.client()
        let crashlytics = Crashlytics.crashlytics()

        crashlytics.setCustomValue(
            apiClient.authenticationProvider.userState.value.rawValue,
            forKey: "UserState" /// <---- Crashes are split, almost evenly, between "signedIn" and "signedOut"
        )

        if apiClient.authenticationProvider.account.meetsMinimumRequirements {
            let account = apiClient.authenticationProvider.account
            crashlytics.setCustomValue(account.id, forKey: "AccountID")
        } else {
            crashlytics.setCustomValue(nil, forKey: "AccountID")
        }

        observer = apiClient.setUserPushToken(data: deviceToken) /// <---- LISTING 3
            .sink(
                receiveCompletion: { result in
                    if case let .failure(error) = result {
                        Logger.error("[PUSH NOTIFICATION] \(error)")
                    }
                },
                receiveValue: {}
            )

        // ... redacted
    }
}

Listing 3: Client setUserPushToken

Listing 3: Client setUserPushToken (intermediate steps)

extension Client {
    func setUserPushToken(data: Data) -> AnyPublisher<Void, Error> {
        let body: [String: String] = ["deviceToken": data.hexString, "platform": "iOS"]

        let encodeBody = Just(body)
            .encode(encoder: JSONEncoder.redactedAppName)

        return Publishers.CombineLatest(
            // Get authentication token
            authenticationProvider.getLatestToken(), /// <---- LISTING 4
            encodeBody
        )
        .flatMap { [baseURL] latestToken, body in
            // Build Request
            URLRequestFactory()
                .publisherForRequest(
                    method: .put,
                    baseURL: baseURL,
                    path: "account/v1/push/register",
                    additionalHeaders: latestToken,
                    body: body
                )
        }
        // Perform API Call
        .flatMap { [session] request in
            session.dataTaskPublisher(for: request)
                .mapError { $0 as Error }
                .map { _ in return () }
                .eraseToAnyPublisher()
        }
        .eraseToAnyPublisher()
    }
}

Listing 4: AuthenticationProvider getLatestToken

Listing 4: AuthenticationProvider getLatestToken (crash site)

class Authentication: AuthenticationProvider, ObservableObject {
    func getTokens() -> AnyPublisher<String, Error> {
        Amplify.Auth.fetchAuthSession() /// <---- CRASH SITE
            .resultPublisher
            .tryMap { authSession -> AuthCognitoTokens? in
                /// Should this be catching exceptions?
                if let cognitoSession = authSession as? AWSAuthCognitoSession {
                    switch cognitoSession.cognitoTokensResult {
                    case let .success(token):
                        return token
                    case let .failure(error):
                        throw error
                    }
                }
                return nil
            }
            .compactMap { $0 }
            .map { $0.idToken }
            .eraseToAnyPublisher()
    }

    func getLatestToken() -> AnyPublisher<[String: String], Error> { /// <---- called by LISTING 3
        getTokens()
            .mapError { $0 as Error }
            .flatMap { idToken -> AnyPublisher<[String: String], Error> in
                let tokenValue = [
                    "Bearer",
                    idToken,
                ]
                .joined(separator: " ")

                let authParam = ["Authorization": tokenValue]

                return Result.Publisher(authParam).eraseToAnyPublisher()
            }
            .eraseToAnyPublisher()
    }
}

[harsh62]

From looking at the code, I would suggest to ensure that Amplify.configure() completes before didRegisterForRemoteNotificationsWithDeviceToken executes. You might need to delay push notification registration until the configuration is complete.

[aokj4ck]

@harsh62 thank you for your suggestion. I added internal state management to ensure Amplify.configure() completes error-free before any call to fetchAuthSession() is made. With our latest release I believe this has resolved the crash issue for us, thank you!