Unexpected Exception

[ivanrlg]

Goals

Discover the cause of the exception

Expected Results

Not have the unexpected exception

Actual Results

Entrando GetTokenAsync: 5/25/2021 7:42:59 PM
The thread 0x3808 has exited with code 0 (0x0).
'FusionMedicalRealm.UWP.exe' (Win32): Loaded 'C:\Windows\System32\Windows.Shell.ServiceHostBuilder.dll'.
The thread 0x41f0 has exited with code 0 (0x0).
Exception thrown at 0x00007FFCAB8F4B89 (KernelBase.dll) in FusionMedicalRealm.UWP.exe: 0x000006D9: There are no more endpoints available from the endpoint mapper.
onecoreuap\base\appmodel\statemanager\roamingrpc\stateroamingrpcclient.cpp(124)\Windows.Storage.ApplicationData.dll!00007FFC801A3CB8: (caller: 00007FFC801A4586) ReturnHr(5) tid(1268) 800706D9 There are no more endpoints available from the endpoint mapper.
    Msg:[c_SignalRoamingDataChange 2]
Entrando CheckSessions: 5/25/2021 7:43:01 PM
Entrando SetUserFromObjet: 5/25/2021 7:43:01 PM
      In GetInstanceAsync  Time: 5/25/2021 7:43:03 PM
Progress Realm: 345 Mb /345 Mb
Exception thrown at 0x00007FFCAB8F4B89 in FusionMedicalRealm.UWP.exe: Microsoft C++ exception: EEMessageException at memory location 0x0000008FEFC7E2C0.
The thread 0x3ee8 has exited with code 0 (0x0).
      In GetInstanceAsync  Time: 5/25/2021 7:43:05 PM
Progress Realm: 345 Mb /345 Mb
Exception thrown at 0x00007FFCAB8F4B89 in FusionMedicalRealm.UWP.exe: Microsoft C++ exception: EEMessageException at memory location 0x0000008FEFC7E2C0.
      In GetInstanceAsync  Time: 5/25/2021 7:43:05 PM
Progress Realm: 345 Mb /345 Mb
Exception thrown at 0x00007FFCAB8F4B89 in FusionMedicalRealm.UWP.exe: Microsoft C++ exception: EEMessageException at memory location 0x0000008FEFC7E2C0.
An unhandled exception of type 'System.NullReferenceException' occurred in Realm.dll
Object reference not set to an instance of an object.

Steps to Reproduce

When installing on a new device after syncing the first time, the exception occurs when I try to search for a record.

I have tried to catch him with a try but it is not possible.

It is important to note that after the exception occurs, the second time I try to enter the app it no longer happens.

Code Sample

 try
            {
                SessionsModel SessionByIdApp = (await SessionsServices.ReadByPredicate(p => p.IdApp == IdApp && p.Email == Email)).Data.LastOrDefault();
                if (SessionByIdApp != null)
                {
                    SessionsModel.Id = SessionByIdApp.Id;
                    SessionsModel.IsActive = SessionByIdApp.IsActive;
                    IResponse = await SessionsServices.Insert(SessionsModel);
                    return await ResponseSessions(Email, Message, SuscriptionIsValid.MaxSession, IResponse, SessionsModel.Id, IsActive, SessionByIdApp.IsActive);
                }

                SessionsModel.IsActive = true;
                IResponse = await SessionsServices.Insert(SessionsModel);

               --------------> here Exepction.
                SessionByIdApp = (await SessionsServices.ReadByPredicate(p => p.IdApp == IdApp && p.Email == Email)).Data.LastOrDefault();
                return await ResponseSessions(Email, Message, SuscriptionIsValid.MaxSession, IResponse, SessionByIdApp.Id, IsActive, SessionByIdApp.IsActive);

            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
                return null;
            }

        public async Task<IDataResponse<IEnumerable<SessionsModel>>> ReadAsync(Expression<Func<SessionsModel, bool>> predicate)
        {
            IEnumerable<Sessions> resultDto;
            IEnumerable<SessionsModel> result;

            var realmInstance = await _realmManager.GetInstanceAsync();
            if (realmInstance == null)
                return new DataResponse<IEnumerable<SessionsModel>>(null, false, "Realm instance can't be null");

            var afterParameter = Expression.Parameter(typeof(Sessions), predicate.Name);
            var visitor = new ExpressionExtension(predicate, afterParameter);
            var newPredicate = Expression.Lambda<Func<Sessions, bool>>(visitor.Visit(predicate.Body), afterParameter);

            resultDto = realmInstance.All<Sessions>()
                                     .Where(newPredicate);
            result = resultDto.ToModel();

            return new DataResponse<IEnumerable<SessionsModel>>(result, result != null);
        }

Image Exception:
https://ibb.co/fX0q8Hn

Version of Realm and Tooling

• Realm Object Server Version: ? (you can see this as well in Studio once connected to a Realm instance)
• Flavor:
  Xamarin

Android & UWP.

Client SDK Version: Realm 10.1.4.
Client OS & Version: Android 9/10. / Windows 10.
Microsoft Visual Studio Community 2019
Version 16.9.6

[papafe]

Hi @ivanrlg. Does this kind of exception happen only on UWP or also on iOS/Android?
Also, have you maybe tried to use any of the beta versions of Realm? The latest one is version 10.2.0-beta.2.

[nirinchev]

Can you try removing the .Where clause from resultDto = realmInstance.All<Sessions>().Where(newPredicate);? I can easily imagine that manually created predicate breaking some assumptions in the realm query engine.

[ivanrlg]

Hi @ivanrlg. Does this kind of exception happen only on UWP or also on iOS/Android?
Also, have you maybe tried to use any of the beta versions of Realm? The latest one is version 10.2.0-beta.2.

Hi @papafe, this happens in UWP, in Android I think the same although it happens slightly differently. I haven't tried that version, I will and let you know.

[ivanrlg]

Can you try removing the .Where clause from resultDto = realmInstance.All<Sessions>().Where(newPredicate);? I can easily imagine that manually created predicate breaking some assumptions in the realm query engine.

Hi @nirinchev, ok I'm going to try as you tell me, I'm curious that it only happens after the first synchronization (when the installation is new) then it doesn't happen.

[ivanrlg]

Hi @papafe / @nirinchev probe with version 10.2.0-beta.2 and it keeps giving the same error.

But, I think I figured it out, all this started to know the initial download in the first sync, so comment this code:

OnProgress = progress =>
{
 Debug.WriteLine($"Progress Realm: {progress.TransferredBytes / 1000000} Mb /{progress.TransferableBytes / 1000000} Mb");
}

and vualá, the exception no longer happened.

Again curious that it only happens the first time.

If you wish, you can close the case.

In the same way, I will leave the last message obtained here if I did not comment on the above.

System.InvalidCastException: 'Unable to cast object of type 'System.Object[]' to type 'Realms.Sync.ProgressNotificationToken'.'

This exception was originally thrown at this call stack: Realms.Sync.SessionHandle.HandleSessionProgress(System.IntPtr, ulong, ulong)

[nirinchev]

Are you by any chance modifying the SyncConfiguration instance used to open the Realm? E.g. is something like that feasible in your code:

this.syncConfig = new SyncConfiguration(...);

public async Task<Realm> GetInstanceAsync()
{
    this.syncConfig.OnProgress = (...);
    return Realm.GetInstanceAsync(this.syncConfig);
};

public Realm GetInstance()
{
    this.syncConfig.OnProgress = null;
    return Realm.GetInstance(this.syncConfig);
}

Asking because I noticed a potential bug where we're not capturing the OnProgress property when GetInstanceAsync is called, which means that modifying it while the Realm is being downloaded might result in unpredictable behavior.

[ivanrlg]

Hi @nirinchev , I tried to fix it as you told me but I couldn't do it exactly the same because I don't use GetInstance but it is with "Async".

Perhaps I am committing a bad practice of using your library, but this way I did not get more errors from incorrect threads and the like. I would still like to learn to do it in the best way.

I was able to modify the GetInstanceAsync and it looks like this:

        public async Task<Realms.Realm> GetInstanceAsync()
        {
            Debug.WriteLine($"      In GetInstanceAsync  Time: {DateTime.Now}");

            this.syncConfig.OnProgress = progress =>
            {
                Debug.WriteLine($"Progress Realm: {progress.TransferredBytes / 1000000} Mb /{progress.TransferableBytes / 1000000} Mb");
            };

            return await Realms.Realm.GetInstanceAsync(this.syncConfig);
        }

But sadly I got the exception again.

The thread 0x15d94 has exited with code 0 (0x0).
In GetInstanceAsync Time: 26/5/2021 7:10:15 p. m.
Progress Realm: 19 Mb /19 Mb
Exception thrown: 'System.EntryPointNotFoundException' in Realm.dll
In GetInstanceAsync Time: 26/5/2021 7:10:18 p. m.
Progress Realm: 19 Mb /19 Mb
Exception thrown: 'System.EntryPointNotFoundException' in Realm.dll
Exception thrown: 'System.NullReferenceException' in Realm.dll
Object reference not set to an instance of an object.

[nirinchev]

Hey @ivanrlg, I'm sorry if I wasn't clear - I wasn't suggesting that this approach would fix things for you, I was just wondering if a pattern like the outlined one is something that may be used in your app. Essentially, I wanted to know if you create a new sync config every time you call Realm.GetInstanceAsync or do you reuse the same config?

[ivanrlg]

Hey @nirinchev , I have a LoginRealm method that I only call when the application is started at that moment there I have the new SyncConfig only that time it is executed, then in the Realm.GetInstanceAsync reuse the one already created.