AADB2C accounts are not removed from the cache in MSAL.Net 2.0.1-internal25504dev

[jmprieur]

Which Version of MSAL are you using ?
MSAL.NET 2.0.1-internal25504dev (Sept 12th, hotfix release candidate)

Which platform has the issue?
All

What authentication flow has the issue?

• Desktop
  • [x ] Interactive
• [ x] Mobile

Repro

1. clone the https://github.com/Azure-Samples/active-directory-b2c-dotnet-desktop repository
2. checkout
3. upgrade to MSAL.NET 2.0.1-internal25504dev
4. build
5. (if you go again through these steps make sure the cache is deleted from the bin\debug folder)
6. Run the App

• sign in with a social identity (for example Google or Microsoft)
• call the API (if you want)
• Sign out
• Sign-in again with a different social identity

Expected behavior
you are signed in with the new identity

Actual behavior
the cache returns an exception
Error Acquiring Token: Microsoft.Identity.Client.MsalServiceException: Returned user identifier does not match the sent user identifier at Microsoft.Identity.Client.Internal.Requests.RequestBase.SaveTokenResponseToCache() at Microsoft.Identity.Client.Internal.Requests.RequestBase.PostTokenRequest() at Microsoft.Identity.Client.Internal.Requests.RequestBase.<RunAsync>d__35.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult() at Microsoft.Identity.Client.PublicClientApplication.<AcquireTokenForUserCommonAsync>d__19.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult() at Microsoft.Identity.Client.PublicClientApplication.<AcquireTokenAsync>d__9.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() at active_directory_b2c_wpf.MainWindow.<SignInButton_Click>d__1.MoveNext() in C:\ghs\s\active-directory-b2c-dotnet-desktop\active-directory-b2c-wpf\MainWindow.xaml.cs:line 39 ErrorCode: user_mismatch StatusCode: 0 Claims:

Analysis
If you run it under debugger, you'll notice that there is an exception in CacheFallbackOperations.RemoveAdalUser because the displayableId is null

System.NullReferenceException HResult=0x80004003 Message=Object reference not set to an instance of an object. Source=Microsoft.Identity.Client StackTrace: at Microsoft.Identity.Core.Cache.CacheFallbackOperations.RemoveAdalUser(ILegacyCachePersistance legacyCachePersistance, String displayableId, ISet`1 environmentAliases, String identifier) in C:\gh\adal.net\core\src\Cache\CacheFallbackOperations.cs:line 186
this exception is logged, and does not prevent the cache from being serialized.

[jmprieur]

@jennyf19 @trwalke