FirebaseAuth.getInstance().getCurrentUser().getUid() returning numbers in place of actual user id

[sipersso]

[READ] Step 1: Are you in the right place?

Issues filed here should be about bugs in the code in this repository.
If you have a general question, need help debugging, or fall into some
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• For general technical questions, post a question on StackOverflow
  with the firebase tag.
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• For help troubleshooting your application that does not fall under one
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[REQUIRED] Step 2: Describe your environment

• Android Studio version: 4.1.2
• Firebase Component: Auth
• Component version: 19.3.0 (Firebase UI 6.3.0)

[REQUIRED] Step 3: Describe the problem

I am copying the description of this issue #1927 since I am experiencing the exact same issue.

Here is the description of #1927
"Using FirebaseAuth.getInstance().getCurrentUser().getUid() to get the user id of the user. This method is returning numbers instead of the actual user id in some case. Also, we find the users token is still valid but the user id returning from the SDK is of number example: 101528418014522522531"

I have had this reported by customers a happen a few times, and it has caused authentication to silently break for them, which is unnacceptable.

Steps to reproduce:

Sorry, not able to reproduce the issue and was got from Crashlytics for some users

Relevant Code:

 FirebaseAuth.getInstance().getCurrentUser().getUid()

[google-oss-bot]

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

I didn't want to create a new issue for this, but since #1927 is closed, I am not allowed to make comments or open that issue. This is the same issue as that one.

Updated the issue so I think it follows the template now.

[sipersso]

I am guessing the user has corrupted info in the KeyChain. Apparently the issue persists even if the app is uninstalled.

[sipersso]

This happened again today. Since the problem persists on reinstall it is really hard to fix this for the end user and the app can't be used at all.

[malcolmdeck]

Hey there sipersso, sorry that this issue appears to have fallen between the cracks. Is a user is having a persistent issue, then can always clear the application data or uninstall/reinstall the application to get the current session to clear out. If that doesn't work, check what the user looks like on export as compared with a user not seeing the issue, please :)

As for why this happens, the version of Auth you are using was published over a year ago, so it's difficult for me to track down why that might be happening. Does this still happen on the latest version of the SDK?

[sipersso]

1: The current version I use is 20.0.2 and firebase-bom: 26.5.0. I'll be sure to update it, but I am not using a version that is a year old.
2: Deleting and reinstalling the app is not a great for two reasons. First, the user will loose any data that hasn't been synced since the error happened. Second, deleting and reinstalling doesn't solve the issue since it is caused by data persistent in the keychain.

What the user needs to do is to
1: Reach out to support so they can manually send me their data and I can recover it for them
2: Go to the settings app and clear app data. This will remove all content and clear the keychain for the app.

For the user, this is an awful experience. The weird things it that Firebase Auth is not throwing any errors. I would expect the user to be signed out if the keychain has been corrupted, or at least to get an error somewhere. If the user would have been signed out right away, the impact would be minimal as it would be forced to sign in again. Now, they can go for a long time without really noticing that their login doesn't work, which is awful.

What do you mean by "check what the user looks like on export"?

[sipersso]

This is still an issue. Currently using com.google.firebase:firebase-bom:29.0.0, that affects a small number of users.

[sipersso]

After being in touch with Firebase support (case 10155473) I actually has some more insight on this one. The numbers that getUID returns are not random!

I do see some permission errors in crashlytics related to this error. When auth returns the wrong UID this will cause permission errors down the line

Here is the interesting part. I did an firebase auth:export and searched for the invalid ids. To my surprise I actually found them! It turns out that user.getUid() can sometimes return other identifiers than the UID. In this case id I saw with all numbers was actually the google sign in uid. I also found cases where firebaseUser.getUid() would return an email adress.

Could this be a database migration gone wrong? Do you access these properties by column index?