[Auth]: `credential` property is not set for 'emailAlreadyInUse' errors

[michaelowolf]

Description

I've raised an equivalent issue against Flutterfire at firebase/flutterfire#13268, where most of the detail can be found.

The gist of the issue is that the docs for Flutter suggest that we should be able to retrieve a credential property from the exception when an email is already in use (see https://pub.dev/documentation/firebase_auth/latest/firebase_auth/User/linkWithProvider.html). This is true for web and Android, but not for iOS. As far as I can tell, this means we don't have a way of recovering from this error for a user on iOS without asking them to sign in again.

I expect the relevant piece of code for the iOS SDK is at:

firebase-ios-sdk/FirebaseAuth/Sources/Swift/Utilities/AuthErrorUtils.swift

Line 290 in 936ddf4

static func emailAlreadyInUseError(email: String?) -> Error {

(where no credential is appended to the error).

Reproducing the issue

I don't have means to reproduce this exclusively for the iOS SDK, but reproduction steps for the Flutter SDK can be found at firebase/flutterfire#13268.

Firebase SDK Version

11.0.0

Xcode Version

15.4

Installation Method

CocoaPods

Firebase Product(s)

Authentication, Crashlytics

Targeted Platforms

iOS

Relevant Log Output

No response

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

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Replace this line with the contents of your Package.resolved.

If using CocoaPods, the project's Podfile.lock

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PODS:
  - AppAuth (1.7.5):
    - AppAuth/Core (= 1.7.5)
    - AppAuth/ExternalUserAgent (= 1.7.5)
  - AppAuth/Core (1.7.5)
  - AppAuth/ExternalUserAgent (1.7.5):
    - AppAuth/Core
  - Firebase/Auth (11.0.0):
    - Firebase/CoreOnly
    - FirebaseAuth (~> 11.0.0)
  - Firebase/CoreOnly (11.0.0):
    - FirebaseCore (= 11.0.0)
  - Firebase/Crashlytics (11.0.0):
    - Firebase/CoreOnly
    - FirebaseCrashlytics (~> 11.0.0)
  - firebase_auth (5.3.0):
    - Firebase/Auth (= 11.0.0)
    - firebase_core
    - Flutter
  - firebase_core (3.5.0):
    - Firebase/CoreOnly (= 11.0.0)
    - Flutter
  - firebase_crashlytics (4.1.2):
    - Firebase/Crashlytics (= 11.0.0)
    - firebase_core
    - Flutter
  - FirebaseAppCheckInterop (11.2.0)
  - FirebaseAuth (11.0.0):
    - FirebaseAppCheckInterop (~> 11.0)
    - FirebaseAuthInterop (~> 11.0)
    - FirebaseCore (~> 11.0)
    - FirebaseCoreExtension (~> 11.0)
    - GoogleUtilities/AppDelegateSwizzler (~> 8.0)
    - GoogleUtilities/Environment (~> 8.0)
    - GTMSessionFetcher/Core (~> 3.4)
    - RecaptchaInterop (~> 100.0)
  - FirebaseAuthInterop (11.2.0)
  - FirebaseCore (11.0.0):
    - FirebaseCoreInternal (~> 11.0)
    - GoogleUtilities/Environment (~> 8.0)
    - GoogleUtilities/Logger (~> 8.0)
  - FirebaseCoreExtension (11.2.0):
    - FirebaseCore (~> 11.0)
  - FirebaseCoreInternal (11.2.0):
    - "GoogleUtilities/NSData+zlib (~> 8.0)"
  - FirebaseCrashlytics (11.0.0):
    - FirebaseCore (~> 11.0)
    - FirebaseInstallations (~> 11.0)
    - FirebaseRemoteConfigInterop (~> 11.0)
    - FirebaseSessions (~> 11.0)
    - GoogleDataTransport (~> 10.0)
    - GoogleUtilities/Environment (~> 8.0)
    - nanopb (~> 3.30910.0)
    - PromisesObjC (~> 2.4)
  - FirebaseInstallations (11.2.0):
    - FirebaseCore (~> 11.0)
    - GoogleUtilities/Environment (~> 8.0)
    - GoogleUtilities/UserDefaults (~> 8.0)
    - PromisesObjC (~> 2.4)
  - FirebaseRemoteConfigInterop (11.2.0)
  - FirebaseSessions (11.2.0):
    - FirebaseCore (~> 11.0)
    - FirebaseCoreExtension (~> 11.0)
    - FirebaseInstallations (~> 11.0)
    - GoogleDataTransport (~> 10.0)
    - GoogleUtilities/Environment (~> 8.0)
    - GoogleUtilities/UserDefaults (~> 8.0)
    - nanopb (~> 3.30910.0)
    - PromisesSwift (~> 2.1)
  - Flutter (1.0.0)
  - fluttertoast (0.0.2):
    - Flutter
    - Toast
  - google_sign_in_ios (0.0.1):
    - AppAuth (>= 1.7.4)
    - Flutter
    - FlutterMacOS
    - GoogleSignIn (~> 7.1)
    - GTMSessionFetcher (>= 3.4.0)
  - GoogleDataTransport (10.1.0):
    - nanopb (~> 3.30910.0)
    - PromisesObjC (~> 2.4)
  - GoogleSignIn (7.1.0):
    - AppAuth (< 2.0, >= 1.7.3)
    - GTMAppAuth (< 5.0, >= 4.1.1)
    - GTMSessionFetcher/Core (~> 3.3)
  - GoogleUtilities/AppDelegateSwizzler (8.0.2):
    - GoogleUtilities/Environment
    - GoogleUtilities/Logger
    - GoogleUtilities/Network
    - GoogleUtilities/Privacy
  - GoogleUtilities/Environment (8.0.2):
    - GoogleUtilities/Privacy
  - GoogleUtilities/Logger (8.0.2):
    - GoogleUtilities/Environment
    - GoogleUtilities/Privacy
  - GoogleUtilities/Network (8.0.2):
    - GoogleUtilities/Logger
    - "GoogleUtilities/NSData+zlib"
    - GoogleUtilities/Privacy
    - GoogleUtilities/Reachability
  - "GoogleUtilities/NSData+zlib (8.0.2)":
    - GoogleUtilities/Privacy
  - GoogleUtilities/Privacy (8.0.2)
  - GoogleUtilities/Reachability (8.0.2):
    - GoogleUtilities/Logger
    - GoogleUtilities/Privacy
  - GoogleUtilities/UserDefaults (8.0.2):
    - GoogleUtilities/Logger
    - GoogleUtilities/Privacy
  - GTMAppAuth (4.1.1):
    - AppAuth/Core (~> 1.7)
    - GTMSessionFetcher/Core (< 4.0, >= 3.3)
  - GTMSessionFetcher (3.5.0):
    - GTMSessionFetcher/Full (= 3.5.0)
  - GTMSessionFetcher/Core (3.5.0)
  - GTMSessionFetcher/Full (3.5.0):
    - GTMSessionFetcher/Core
  - nanopb (3.30910.0):
    - nanopb/decode (= 3.30910.0)
    - nanopb/encode (= 3.30910.0)
  - nanopb/decode (3.30910.0)
  - nanopb/encode (3.30910.0)
  - package_info_plus (0.4.5):
    - Flutter
  - pointer_interceptor_ios (0.0.1):
    - Flutter
  - PromisesObjC (2.4.0)
  - PromisesSwift (2.4.0):
    - PromisesObjC (= 2.4.0)
  - RecaptchaInterop (100.0.0)
  - Toast (4.1.1)
  - url_launcher_ios (0.0.1):
    - Flutter
  - webview_flutter_wkwebview (0.0.1):
    - Flutter
    - FlutterMacOS

DEPENDENCIES:
  - firebase_auth (from `.symlinks/plugins/firebase_auth/ios`)
  - firebase_core (from `.symlinks/plugins/firebase_core/ios`)
  - firebase_crashlytics (from `.symlinks/plugins/firebase_crashlytics/ios`)
  - Flutter (from `Flutter`)
  - fluttertoast (from `.symlinks/plugins/fluttertoast/ios`)
  - google_sign_in_ios (from `.symlinks/plugins/google_sign_in_ios/darwin`)
  - package_info_plus (from `.symlinks/plugins/package_info_plus/ios`)
  - pointer_interceptor_ios (from `.symlinks/plugins/pointer_interceptor_ios/ios`)
  - url_launcher_ios (from `.symlinks/plugins/url_launcher_ios/ios`)
  - webview_flutter_wkwebview (from `.symlinks/plugins/webview_flutter_wkwebview/darwin`)

SPEC REPOS:
  trunk:
    - AppAuth
    - Firebase
    - FirebaseAppCheckInterop
    - FirebaseAuth
    - FirebaseAuthInterop
    - FirebaseCore
    - FirebaseCoreExtension
    - FirebaseCoreInternal
    - FirebaseCrashlytics
    - FirebaseInstallations
    - FirebaseRemoteConfigInterop
    - FirebaseSessions
    - GoogleDataTransport
    - GoogleSignIn
    - GoogleUtilities
    - GTMAppAuth
    - GTMSessionFetcher
    - nanopb
    - PromisesObjC
    - PromisesSwift
    - RecaptchaInterop
    - Toast

EXTERNAL SOURCES:
  firebase_auth:
    :path: ".symlinks/plugins/firebase_auth/ios"
  firebase_core:
    :path: ".symlinks/plugins/firebase_core/ios"
  firebase_crashlytics:
    :path: ".symlinks/plugins/firebase_crashlytics/ios"
  Flutter:
    :path: Flutter
  fluttertoast:
    :path: ".symlinks/plugins/fluttertoast/ios"
  google_sign_in_ios:
    :path: ".symlinks/plugins/google_sign_in_ios/darwin"
  package_info_plus:
    :path: ".symlinks/plugins/package_info_plus/ios"
  pointer_interceptor_ios:
    :path: ".symlinks/plugins/pointer_interceptor_ios/ios"
  url_launcher_ios:
    :path: ".symlinks/plugins/url_launcher_ios/ios"
  webview_flutter_wkwebview:
    :path: ".symlinks/plugins/webview_flutter_wkwebview/darwin"

SPEC CHECKSUMS:
  AppAuth: 501c04eda8a8d11f179dbe8637b7a91bb7e5d2fa
  Firebase: 9f574c08c2396885b5e7e100ed4293d956218af9
  firebase_auth: f27287630c4d9e2c3c63e64d9240822ad6b07e5b
  firebase_core: 2ec6b789859c7c24766344ec71fdf78639402d56
  firebase_crashlytics: 60630a0f91ee432275fa1660fd8593079761448a
  FirebaseAppCheckInterop: ea21450529cf0ebd132788dd8916a0269abc684f
  FirebaseAuth: d5cf28be74d7e82257f6a3f717509eff70d3cf4a
  FirebaseAuthInterop: 47c09558af5d1b31f16fb352387c72d4804f4a24
  FirebaseCore: 3cf438f431f18c12cdf2aaf64434648b63f7e383
  FirebaseCoreExtension: cda74ddfb001224bd8fd1d6e74698b4ed07803de
  FirebaseCoreInternal: 0c569513412da9f3b31bd0b340013bbee8f295c5
  FirebaseCrashlytics: 745d8f0221fe49c62865391d1bf56f5a12eeec0b
  FirebaseInstallations: 771177d89d6c451dc6e50085ec82e2fc77ed0a4a
  FirebaseRemoteConfigInterop: 477b26fdeb8fb5fbaf22fa9db5343b42289dc7db
  FirebaseSessions: adcec8b72d0066a385e3affcd1bcb1ebb3908ce6
  Flutter: e0871f40cf51350855a761d2e70bf5af5b9b5de7
  fluttertoast: e9a18c7be5413da53898f660530c56f35edfba9c
  google_sign_in_ios: 07375bfbf2620bc93a602c0e27160d6afc6ead38
  GoogleDataTransport: aae35b7ea0c09004c3797d53c8c41f66f219d6a7
  GoogleSignIn: d4281ab6cf21542b1cfaff85c191f230b399d2db
  GoogleUtilities: 26a3abef001b6533cf678d3eb38fd3f614b7872d
  GTMAppAuth: f69bd07d68cd3b766125f7e072c45d7340dea0de
  GTMSessionFetcher: 5aea5ba6bd522a239e236100971f10cb71b96ab6
  nanopb: fad817b59e0457d11a5dfbde799381cd727c1275
  package_info_plus: 58f0028419748fad15bf008b270aaa8e54380b1c
  pointer_interceptor_ios: 508241697ff0947f853c061945a8b822463947c1
  PromisesObjC: f5707f49cb48b9636751c5b2e7d227e43fba9f47
  PromisesSwift: 9d77319bbe72ebf6d872900551f7eeba9bce2851
  RecaptchaInterop: 7d1a4a01a6b2cb1610a47ef3f85f0c411434cb21
  Toast: 1f5ea13423a1e6674c4abdac5be53587ae481c4e
  url_launcher_ios: 5334b05cef931de560670eeae103fd3e431ac3fe
  webview_flutter_wkwebview: 0982481e3d9c78fd5c6f62a002fcd24fc791f1e4

PODFILE CHECKSUM: a57f30d18f102dd3ce366b1d62a55ecbef2158e5

COCOAPODS: 1.15.2

[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.

[paulb777]

I started investigating and the issue seems to go beyond the SDK and I don't see what the other platforms are doing differently.

The backend doesn't return anything beyond that there is an EMAIL_EXISTS error.

(lldb) po decodedDictionary 
▿ 1 element
  ▿ 0 : 2 elements
    - key : "error"
    ▿ value : AnyHashable([AnyHashable("code"): AnyHashable(400), AnyHashable("message"): AnyHashable("EMAIL_EXISTS"), AnyHashable("errors"): AnyHashable([AnyHashable([AnyHashable("message"): AnyHashable("EMAIL_EXISTS"), AnyHashable("domain"): AnyHashable("global"), AnyHashable("reason"): AnyHashable("invalid")])])])
      ▿ value : 3 elements
        ▿ 0 : 2 elements
          ▿ key : AnyHashable("code")
            - value : "code"
          ▿ value : AnyHashable(400)
            - value : 400
        ▿ 1 : 2 elements
          ▿ key : AnyHashable("message")
            - value : "message"
          ▿ value : AnyHashable("EMAIL_EXISTS")
            - value : "EMAIL_EXISTS"
        ▿ 2 : 2 elements
          ▿ key : AnyHashable("errors")
            - value : "errors"
          ▿ value : AnyHashable([AnyHashable([AnyHashable("message"): AnyHashable("EMAIL_EXISTS"), AnyHashable("domain"): AnyHashable("global"), AnyHashable("reason"): AnyHashable("invalid")])])
            ▿ value : 1 element
              ▿ 0 : AnyHashable([AnyHashable("message"): AnyHashable("EMAIL_EXISTS"), AnyHashable("domain"): AnyHashable("global"), AnyHashable("reason"): AnyHashable("invalid")])
                ▿ value : 3 elements
                  ▿ 0 : 2 elements
                    ▿ key : AnyHashable("message")
                      - value : "message"
                    ▿ value : AnyHashable("EMAIL_EXISTS")
                      - value : "EMAIL_EXISTS"
                  ▿ 1 : 2 elements
                    ▿ key : AnyHashable("domain")
                      - value : "domain"
                    ▿ value : AnyHashable("global")
                      - value : "global"
                  ▿ 2 : 2 elements
                    ▿ key : AnyHashable("reason")
                      - value : "reason"
                    ▿ value : AnyHashable("invalid")
                      - value : "invalid"