didRegister/didFailToRegisterForRemoteNotifications callbacks not called when FirebaseAuth is linked via SPM

[elliottetzkorn]

Description

When the FirebaseAuth library is included as a Swift Package Manager dependency in an iOS project, and FirebaseApp.configure() is called during application launch, the standard iOS AppDelegate callbacks for APNs registration (application(:didRegisterForRemoteNotificationsWithDeviceToken:) and application(:didFailToRegisterForRemoteNotificationsWithError:)) are never invoked.

This issue occurs even in a minimal reproduction case within the project where only FirebaseApp.configure() is called and no other Firebase APIs are used immediately.

Crucially, APNs registration succeeds (the callbacks are invoked) under the following conditions:

1. If FirebaseApp.configure() is not called.
2. If FirebaseApp.configure() is called, but the FirebaseAuth product is removed from the SPM dependencies (even if other Firebase products like FirebaseAnalytics, FirebaseFirestore, FirebaseFunctions, FirebaseStorage remain).

This suggests an issue within the initialization process triggered by the presence of the FirebaseAuth library itself, interfering with the system-level APNs registration mechanism. The problem persists even when using programmatic FirebaseOptions for configuration instead of GoogleService-Info.plist. All necessary capabilities (Push Notifications, Background Modes - Remote Notifications) and Info.plist/.entitlements entries appear correct, and APNs registration works flawlessly in a separate clean project with FirebaseAuth. The original project exhibiting this issue was also rebuilt from scratch by copying source files into a new project structure, but the problem persisted.

Reproducing the issue

1. Create an iOS project using SwiftUI and the AppDelegate lifecycle (@UIApplicationDelegateAdaptor).
2. Add the firebase-ios-sdk Swift Package. Include at least FirebaseAnalytics and FirebaseAuth as product dependencies.
3. Set up the necessary capabilities (Push Notifications, Background Modes - Remote Notifications) and entitlements.
4. Use a minimal AppDelegate that calls FirebaseApp.configure() in didFinishLaunchingWithOptions and implements the standard push registration flow (requestAuthorization, registerForRemoteNotifications) and the two delegate callbacks (didRegister..., didFailToRegister...) with simple print statements. (See relevant log info below for example code structure).
5. Run the app on a physical device.
6. Observe that after the "Requesting APNS registration..." log, neither the success nor failure APNs delegate callbacks are ever printed.
   7/ Verify: Remove only the FirebaseAuth product from the Swift Package dependencies, clean the build folder, delete derived data, restart Xcode, and run again. Observe that the didRegisterForRemoteNotificationsWithDeviceToken callback is now invoked successfully.

Firebase SDK Version

Tested 11.12.0, 11.11.0 and 11.9.0

Xcode Version

16.3

Installation Method

Swift Package Manager

Firebase Product(s)

Authentication

Targeted Platforms

iOS

Relevant Log Output

[Firebase/Core][I-COR000001] Configuring the default Firebase app...
[Firebase/Core][I-COR000004] Firebase App ID: 1:XXXXXXXXXX:ios:XXXXXXXXXXXXXX
[Firebase/Core][I-COR000012] Firebase Analytics enabled
[Firebase/Core][I-COR000005] The default Firebase app has been configured successfully.
[PushTest] Permission granted: true
[PushTest] Requesting APNS registration...
// <<< NO FURTHER "SUCCESS" OR "FAILED" LOGS APPEAR >>>

If using Swift Package Manager, the project's Package.resolved

{
"originHash" : "c63c63846d9c539229e96de38d6af51417e28c0ee9a0bc48bd0f0f19d923c329",
"pins" : [
{
"identity" : "abseil-cpp-binary",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/abseil-cpp-binary.git",
"state" : {
"revision" : "bbe8b69694d7873315fd3a4ad41efe043e1c07c5",
"version" : "1.2024072200.0"
}
},
{
"identity" : "app-check",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/app-check.git",
"state" : {
"revision" : "61b85103a1aeed8218f17c794687781505fbbef5",
"version" : "11.2.0"
}
},
{
"identity" : "firebase-ios-sdk",
"kind" : "remoteSourceControl",
"location" : "https://github.com/firebase/firebase-ios-sdk.git",
"state" : {
"revision" : "fbd463894af94d90eb4d6a4e54080459a8179519",
"version" : "11.12.0"
}
},
{
"identity" : "googleappmeasurement",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/GoogleAppMeasurement.git",
"state" : {
"revision" : "f7460ea630bddf172115c28493ae8b3798d95ce3",
"version" : "11.12.0"
}
},
{
"identity" : "googledatatransport",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/GoogleDataTransport.git",
"state" : {
"revision" : "617af071af9aa1d6a091d59a202910ac482128f9",
"version" : "10.1.0"
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},
{
"identity" : "googleutilities",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/GoogleUtilities.git",
"state" : {
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{
"identity" : "grpc-binary",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/grpc-binary.git",
"state" : {
"revision" : "cc0001a0cf963aa40501d9c2b181e7fc9fd8ec71",
"version" : "1.69.0"
}
},
{
"identity" : "gtm-session-fetcher",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/gtm-session-fetcher.git",
"state" : {
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"version" : "4.4.0"
}
},
{
"identity" : "interop-ios-for-google-sdks",
"kind" : "remoteSourceControl",
"location" : "https://github.com/google/interop-ios-for-google-sdks.git",
"state" : {
"revision" : "040d087ac2267d2ddd4cca36c757d1c6a05fdbfe",
"version" : "101.0.0"
}
},
{
"identity" : "leveldb",
"kind" : "remoteSourceControl",
"location" : "https://github.com/firebase/leveldb.git",
"state" : {
"revision" : "a0bc79961d7be727d258d33d5a6b2f1023270ba1",
"version" : "1.22.5"
}
},
{
"identity" : "nanopb",
"kind" : "remoteSourceControl",
"location" : "https://github.com/firebase/nanopb.git",
"state" : {
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"version" : "2.30910.0"
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"identity" : "promises",
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"location" : "https://github.com/google/promises.git",
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"version" : "1.29.0"
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}
],
"version" : 3
}

If using CocoaPods, the project's Podfile.lock

Expand Podfile.lock snippet

Replace this line with the contents of your Podfile.lock!

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[elliottetzkorn]

I just tested with Xcode 16.2 and had the same bug, so I think the issue must be with iOS 18.4.1 or my device, the iPhone 16e..

[paulb777]

Thanks for the report. Does the issue occur on the iOS simulator? On earlier versions of iOS?

Disabling swizzling may be a workaround - https://firebase.google.com/docs/auth/ios/phone-auth#appendix:-using-phone-sign-in-without-swizzling

[elliottetzkorn]

I only can test on my physical device since APN wouldn't work anyways on a simulator. Disabling swizzling did indeed solve the issue thanks. Will this issue remain open until it is worked out why swizzling is failing here?

[paulb777]

Yep, there's likely an underlying iOS change causing this.

We'll leave the issue open to investigate since the product shouldn't fail in the default configuration.