[Bug] Json serializer fails on iOS in release mode (AOT) - regression in v4.52.0

Stack trace

System.ExecutionEngineException: Attempting to JIT compile method '(wrapper delegate-invoke) void <Module>:invoke_callvirt_void_Dictionary`2<string, JToken>_string_JToken (System.Collections.Generic.Dictionary`2<string, Microsoft.Identity.Json.Linq.JToken>,string,Microsoft.Identity.Json.Linq.JToken)' while running in aot-only mode. See https://docs.microsoft.com/xamarin/ios/internals/limitations for more information.

  ?, in int ActionCallInstruction<Dictionary<string, JToken>, string, JToken>.Run(InterpretedFrame)
  ?, in void Interpreter.Run(InterpretedFrame)
  ?, in object LightLambda.Run(params object[])
  ?, in object DelegateHelpers.FuncThunk2<object, object[], object>(Func<object[], object> handler, object t1, object[] t2)
  ?, in void <>c__DisplayClass45_1.<SetExtensionDataDelegates>b__0(?)+(object o, string key, object value) => { }
  ?, in void JsonSerializerInternalReader.SetExtensionData(JsonObjectContract contract, JsonProperty member, JsonReader reader, string memberName, object o)
Microsoft.Identity.Json.JsonSerializationException: Error setting value in extension data for type 'Microsoft.Identity.Client.OAuth2.MsalTokenResponse'. Path 'not_before', line 1, position 3126.
  ?, in void JsonSerializerInternalReader.SetExtensionData(JsonObjectContract contract, JsonProperty member, JsonReader reader, string memberName, object o)
  ?, in object JsonSerializerInternalReader.PopulateObject(object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, string id)
  ?, in object JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, object existingValue)
  ?, in object JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, object existingValue)
  ?, in object JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, bool checkAdditionalContent)
  ?, in object JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
  ?, in object JsonConvert.DeserializeObject(string value, Type type, JsonSerializerSettings settings)
  ?, in MsalTokenResponse JsonConvert.DeserializeObject<MsalTokenResponse>(string value, JsonSerializerSettings settings)
  ?, in MsalTokenResponse JsonHelper.DeserializeFromJson<MsalTokenResponse>(string json)
  ?, in MsalTokenResponse OAuth2Client.CreateResponse<MsalTokenResponse>(HttpResponse response, RequestContext requestContext)
  ?, in async void <ExecuteRequestAsync>d__12<MsalTokenResponse>.MoveNext()
  ?, in async Task<MsalTokenResponse> OAuth2Client.GetTokenAsync(Uri endPoint, RequestContext requestContext, bool addCommonHeaders, Func<OnBeforeTokenRequestData, Task> onBeforePostRequestHandler)
  ?, in async Task<MsalTokenResponse> TokenClient.SendHttpAndClearTelemetryAsync(string tokenEndpoint, ILoggerAdapter logger)
  ?, in async Task<MsalTokenResponse> TokenClient.SendTokenRequestAsync(IDictionary<string, string> additionalBodyParameters, string scopeOverride, string tokenEndpointOverride, CancellationToken cancellationToken)
  ?, in async Task<MsalTokenResponse> InteractiveRequest.GetTokenResponseAsync(CancellationToken cancellationToken)
  ?, in async Task<AuthenticationResult> InteractiveRequest.ExecuteAsync(CancellationToken cancellationToken)
  ?, in async Task<AuthenticationResult> RequestBase.RunAsync(CancellationToken cancellationToken)
  ?, in async Task<AuthenticationResult> PublicClientExecutor.ExecuteAsync(AcquireTokenCommonParameters commonParameters, AcquireTokenInteractiveParameters interactiveParameters, CancellationToken cancellationToken)

Which version of MSAL.NET are you using?

Microsoft.Identity.Client 4.52.0 Microsoft.Identity.Client.Extensions.Msal 2.28.0

Platform

MAUI v7.0.59

What authentication flow has the issue?

• Desktop / Mobile
  • Interactive
  • Integrated Windows Authentication
  • Username Password
  • Device code flow (browserless)
• Web app
  • Authorization code
  • On-Behalf-Of
• Daemon app
  • Service to Service calls

Is this a new or existing app?

The app is in production, and I have upgraded to a new version of MSAL.

Possible solution

Fallback to v4.51.0 / v2.27.0

[espenrl]

Yes, it is a regression in 4.52.0. It works in 4.51.0

[espenrl]

I think the main problem is return System.Collections.Immutable.ImmutableDictionary<TKey, TValue>.Empty; In my experience AOT doesn’t work well with immutable collections and JSON serialization.