System.Text.Json.JsonReaderException on Android when deserializing JobInfo

[MelissaW990]

Hi Team,

I would be very grateful if anyone could help me with this issue or advise if I am doing something wrong. On Android, I receive the following error for a small number of users:

System.Text.Json.JsonReaderException: ExpectedStartOfValueNotFound, 0x00 LineNumber: 0 | BytePositionInLine: 0.
  at void ThrowHelper.ThrowJsonReaderException(ref Utf8JsonReader, ExceptionResource, byte, ReadOnlySpan<byte>)()
  at bool Utf8JsonReader.ConsumeValue(byte)()
  at bool Utf8JsonReader.ReadFirstToken(byte)()
  at bool Utf8JsonReader.ReadSingleSegment()()
  at bool Utf8JsonReader.Read()()
  at bool JsonConverter<JobInfo>.ReadCore(ref Utf8JsonReader, out JobInfo, JsonSerializerOptions, ref ReadStack)()
System.Text.Json.JsonException: ExpectedStartOfValueNotFound, 0x00 Path: $ | LineNumber: 0 | BytePositionInLine: 0.
  at void ThrowHelper.ReThrowWithPath(ref ReadStack, JsonReaderException)()
  at bool JsonConverter<JobInfo>.ReadCore(ref Utf8JsonReader, out JobInfo, JsonSerializerOptions, ref ReadStack)()
  at JobInfo JsonTypeInfo<JobInfo>.Deserialize(ref Utf8JsonReader, ref ReadStack)()
  at object JsonTypeInfo<JobInfo>.DeserializeAsObject(ref Utf8JsonReader, ref ReadStack)()
  at object JsonSerializer.ReadFromSpanAsObject(ReadOnlySpan<byte>, JsonTypeInfo, int?) x 2()
  at object JsonSerializer.Deserialize(string, Type, JsonSerializerOptions)()
  at object DefaultSerializer.Deserialize(Type objectType, string value)()
  at JobInfo DefaultSerializer.Deserialize<JobInfo>(string value)()
  at Dictionary<string, JobInfo> FileSystemRepository.Load<JobInfo>()()
  at void FileSystemRepository.InTransaction<JobInfo>(Action<Dictionary<string, JobInfo>> action)()
  at IList<JobInfo> FileSystemRepository.GetList<JobInfo>(Expression<Func<JobInfo, bool>> expression)()
  at IList<JobInfo> AbstractJobManager.GetJobs()()
  at async Task JobLifecycleTask.RunJobs()()
System.AggregateException: TaskExceptionHolder_UnhandledException

As my Shiny Job carries out some JSON deserialisation, I initially thought it was my own code throwing this exception when deserialising some user data. After a new release, I see the issue persists.

I will admit in the beginning, I was accidentally registering the job twice, once in MauiProgram, and again in a ViewModel. I implemented some clean-up code in the next release to cancel the job completely on launch (in a hope to delete the two registrations if they existed) and then register it again, but again, I am still seeing the exception persist.

I haven't opened an issue as I can't replicate the exception therefore can't provide a sample.

I appreciate anyone who has taken the time to read this.

Many thanks, Melissa

[aritchie]

What version of Shiny? Did you do an upgrade? What's the locale of the device? What's the make/model & android version of the device(s)? I need as much detail as possible.

Please note that this forum is going offline and is being moved to the mauiverse.net discord as of this weekend.

[MelissaW990]

Thank you for responding Allan,

Shiny version: 4.0.1

The exception doesn't seem to be associated with any specific Android device or version of Android. But the sentry events I have show it is happening on:

• Android versions: 10, 12, 13, 14, 16
• Devices: SM-A226B, SM-A556E, SM-A715F, SM-A415F, SM-G981B, SM-G781B, SM-G998B, LE2123, moto g(7) plus, Pixel 6 Pro, Pixel 9 Pro XL

There are thousands of events being triggered over some time for a relatively small (<100) number of customers, and any I have checked are all in UK/Ireland. However, that is where majority of our customers are based so this is not unusual and I wouldn't consider it a trend. There are many, many customers in the same locale who are not having any issue with it.

And yes sorry, I only saw that it was moving after I posted the discussion.

[aritchie]

It looks like your jobinfo files are empty. I'm not sure what would cause that. You're going to get lots of events per user because the job will keep trying to be triggered. You can switch to v5 beta which doesn't use jobinfo any longer.

[MelissaW990]

Will upgrade for the next release :)