`updateChatMessageTtl` is not implemented and resulted in exception thrown

[DamienLaw]

updateChatMessageTtl is not implemented and when received from Telegram will result in an exception thrown.

Could not create an instance of type TdLib.TdApi+Object. Type is an interface or abstract class and cannot be instantiated. Path '@type', line 1, position 9.

tdsharp/TdLib/Bindings/Receiver.cs

Lines 43 to 69 in 9bebcfa

	private void ProcessEvents()
	{
	var ct = _cts.Token;
	while (!ct.IsCancellationRequested)
	{
	var data = _tdJsonClient.Receive(0.1);
	if (!string.IsNullOrEmpty(data))
	{
	try
	{
	var structure = JsonConvert.DeserializeObject<TdApi.Object>(data, _converter);
	Received?.Invoke(this, structure);
	if (structure is TdApi.Update.UpdateAuthorizationState update)
	{
	AuthorizationStateChanged?.Invoke(this, update.AuthorizationState);
	}
	}
	catch (Exception e)
	{
	ExceptionThrown?.Invoke(this, e);
	}
	}
	}
	}

This is because on line 54, the deserialization will fallback to TdApi.Object if the type is not found.

tdsharp/TdLib.Api/Object.cs

Lines 10 to 15 in 9bebcfa

	public abstract class Object
	{
	[JsonProperty("@type")] public virtual string DataType { get; set; }
	[JsonProperty("@extra")] public virtual string Extra { get; set; }
	}

And TdApi.Object is abstract. No deserialization can be performed on abstract class.

[ForNeVeR]

Any idea what exactly is this message? I cannot find it in td_api.tl from tdlib: https://github.com/tdlib/td/blob/master/td/generate/scheme/td_api.tl

[ForNeVeR]

In fact, it is only mentioned in an old changelog (from 1.8.0, 2021-12-29), and nowhere else.

Are you sure it exists? Under what circumstances do you receive that?

[DamienLaw]

When I was running the C# sample TdLib.Samples.GetChats.

I'm only getting error on one of my accounts. But not on the other.

[ForNeVeR]

Why do you think that's updateChatMessageTtl and not something else? Have you found that in debug mode?

[DamienLaw]

Yes, I was running the sample in debug mode when I was hit by the exception.

The @type indicated that it's updateChatMessageTtl (underlined at the lower left of the screenshot).

[ForNeVeR]

I would recommend opening an issue upstream.

There is no such type in the actual tdlib sources, and I don't understand how we should generate it.

[DamienLaw]

The reference is specified here and here.

Does it help?

[ForNeVeR]

These links look identical. And, unfortunately, no, it does not help.

There are still no any details about this class in the .tl specification. So, we cannot generate it. And it doesn't exist in tdlib sources.

[DamienLaw]

These links look identical.

Sorry, the 2nd link supposed to be td_api.h

Perhaps, that class has been removed from the API but the server is still sending it. Is it possible to ignore unrecognised API and logs them instead of throwing unhandled exceptions and killing the client?

[ForNeVeR]

Perhaps, that class has been removed from the API but the server is still sending it.

On this, I unfortunately have no idea. This is a question for upstream developers.

Is it possible to ignore unrecognised API and logs them instead of throwing unhandled exceptions and killing the client?

But we are doing that already. An ExceptionThrown event is emitted when there's an exception in the Receiver loop; there are no unhandled exceptions anywhere.

(Also, I found that the exception is not even exposed anywhere, I'll create an improvement request for that matter.)

Do you suggest some other behavior?