Failure to fetch token fails to report server error

[richardcrichardc]

Description

Failure to fetch token fails to report server error.

I.e. error message 'Invalid fetch response, expected 'token' or 'Error' key' is shown, instead of the error after the 'Error' key returned by the FCM service.

Reproducing the issue

This issue is evident for some or all of the problems indicated by this issue in the Flutter Firebase library: firebase/flutterfire#13558

The error can be found by inspecting the code here:

firebase-ios-sdk/FirebaseMessaging/Sources/Token/FIRMessagingTokenFetchOperation.m

Line 148 in 00674c8

if (errorValue.length) {

The error key is parsed into errorValue on out on line 146. Lines 148-176 do not assign the error to responseError in all cases, including when errorValue is the string 'TOO_MANY_REGISTRATIONS'. Lines 177-183 then report the key 'Error' was not set.

Firebase SDK Version

latest

Xcode Version

n/a

Installation Method

CocoaPods

Firebase Product(s)

Messaging

Targeted Platforms

iOS

Relevant Log Output

No response

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

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If using CocoaPods, the project's Podfile.lock

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[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]

Looks like it may be related to #13969

[leojaygoogle]

Thanks for the report! I agree that the error message can be improved to make it easier to debug fetch token failures. I will send out a PR to fix that.