Use Smart Lock with Firebase Auth Email+Password accounts

Question

I'm not using FirebaseUI. With FirebaseUI I managed to store the email and password into Smart Lock after creating a new account for an user of the app.

I had to remove FirebaseUI, because it doesn't allow a precise control over which account gets signed in with silent sign-in, and I rely on that to switch between the multiple accounts one user can have on a device.

Using the CredentialsClient I had no problems retrieving those passwords; the user got presented a Dialog where he could choose the account and the password would get handed over to the app via onActivityResult. I followed Google's guide Retrieve a user's stored credentials in order to do this.

But I am unable to save the new email and password as a new credential. I always get the error com.google.android.gms.common.api.CommonStatusCodes.SIGN_IN_REQUIRED with the message Passphrase required in form of an com.google.android.gms.common.api.ApiException.

This is my code:

CredentialsOptions options = new CredentialsOptions.Builder()
        .forceEnableSaveDialog()
        .build();

CredentialsClient mCredentialsClient = Credentials.getClient(MainActivity.activity, options);

Credential credential = new Credential.Builder("[email protected]")
        .setPassword("dummy-password")
        .build();

mCredentialsClient.save(credential).addOnCompleteListener(new OnCompleteListener<Void>() {
    @Override public void onComplete(@NonNull Task<Void> task) {
        if (task.isSuccessful()) {
            LogWrapper.i(TAG, "Credentials saved");
        }
        else if (task.getException() instanceof ResolvableApiException) {
            ResolvableApiException rae = (ResolvableApiException) task.getException();
            LogWrapper.e(TAG, "RAE EXCEPTION WHEN SAVING PASSWORD:", rae);
        }
        else {
            Exception e = task.getException();
            LogWrapper.e(TAG, "EXCEPTION WHEN SAVING PASSWORD:", e);
        }
    }
});

I have three Google Accounts on that device, one of which has configured a passphrase for syncing, the other two don't.

Keep your info private

With a passphrase, you can use Google's cloud to store and sync your Chrome data without letting Google read it. Your payment methods and addresses from Google Pay aren't encrypted by a passphrase.

Passphrases are optional. Your synced data is always protected by encryption when it's in transit.

I am not sure if this error message is being caused because of this, that this is the passphrase which is required. But then again I wonder why FirebaseUI had no issues with storing the Credentials, even into the correct account without asking, which is one which doesn't use a passphrase.

I also signed into the account via FirebaseUI's Google Sign-In where I want to save the credentials to, and then executed the code above in order to see if that signed-in user would set the app into a state where it is signed into that Google Account as the error messages seems to expect me to, and willing to save some email and password credentials into that account. That didn't make any difference.

I read Firebase's approach to using Smart Lock, and I can't find any real differences to what I'm doing.

It is basically the same as shown in the CredentialsQuickstart app.

So the question is: What needs to be signed in? Why am I getting this message?

---

Update: I've downloaded and compiled https://github.com/android/identity-samples/tree/master/CredentialsQuickstart and there I'm getting the same error, so this seems to be some more general issue.

This is on Android 10. I've also tried it on another device with Android 9 and there I have the same problem.

Has this API been "deprecated" by this thing called "AutoFill service"? I found an option in "Languages & Input" under "Tools" where there is an AutoFill Service from Google where I can select one account into which the credentials get stored into. And this is configured to use the account which has no passphrase, the one where FirebaseUI correctly stored the Credentials into. I think on a Samsung device it also offers an additional AutoFill service.

That would be this then: https://developer.android.com/guide/topics/text/autofill