Export iOS - newtonsoft parse JSON - Unable to find default constructor for System.Collections.Generic.List

[BriBarthelemy]

Hello,
I have an error from newtonsoft when exported to iOS.

[Ably DEBUG] Debug: 10:45:39.876 Transport State: Error. Error is Unable to find default constructor for System.Collections.Generic.List`1[[IO.Ably.Message, IO.Ably, Version=1.2.15.0, Culture=neutral, PublicKeyToken=70cfghg5c3dhfggb16]].    at Newtonsoft.Json.Utilities.LateBoundReflectionDelegateFactory.CreateDefaultConstructor[T](Type) + 0x124
   at Newtonsoft.Json.Serialization.JsonArrayContract.CreateTemporaryCollection() + 0xd0
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateNewList(JsonReader, JsonArrayContract, Boolean&) + 0xb0
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader, Type, JsonContract, JsonProperty, Object, String) + 0xa0
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader, Type, JsonContract, JsonProperty, JsonContainerContract, JsonProperty, Object) + 0xdc
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty, JsonConverter, JsonContainerContract, JsonProperty, JsonReader, Object) + 0x150
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object, JsonReader, JsonObjectContract, JsonProperty, String) + 0x748
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader, Type, JsonContract, JsonProperty, JsonContainerContract, JsonProperty, Object) + 0x2e4
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader, Type, JsonContract, JsonProperty, JsonContainerContract, JsonProperty, Object) + 0xb8
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader, Type, Boolean) + 0x288
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader, Type) + 0xf0
   at IO.Ably.JsonHelper.DeserializeObject(String value, Type type) + 0x88
   at IO.Ably.JsonHelper.Deserialize[T](String json) + 0x2c
   at IO.Ably.MessageEncoders.MessageHandler.ParseRealtimeData(RealtimeTransportData data) + 0x18
   at IO.Ably.Transport.ConnectionManager.IO.Ably.Transport.ITransportListener.OnTransportDataReceived(RealtimeTransportData data) + 0x2c
   at IO.Ably.Transport.MsWebSocketConnection.<Receive>d__25.MoveNext() + 0x35c

Ably version : 1.2.15

And here is my csproj :

<Project Sdk="Godot.NET.Sdk/4.4.0-beta.3">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <EnableDynamicLoading>true</EnableDynamicLoading>
    <RootNamespace>ProjectA</RootNamespace>
    <!-- use interpreter in ios release -->
    <UseInterpreter Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios' And '$(Configuration)' == 'Release'">true</UseInterpreter>

  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="ably.io" Version="1.2.15" />
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.0" />
    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
    <PackageReference Include="System.Net.Http" Version="4.3.4" />
    
    <TrimmerRootAssembly Include="IO.Ably" />
  </ItemGroup>
  

</Project>

Should I change the Newtonsoft.Json version ?

Already checked on issue but I didn't find something relevant.

Thank you!

┆Issue is synchronized with this Jira Task by Unito

[sacOO7]

@BriBarthelemy ably internally uses old version of newtonsoft, you might like to remove external dependency on newtonsoft wdyt? That way, you should be able to use internal newtonsoft.

[sacOO7]

Though same config. is working for android, windows right 🤔

[sacOO7]

@BriBarthelemy is the issue resolved? let me know about this one 👍

[BriBarthelemy]

Correct.
It works on Android.

To be honest, I'm not an expert, but from what I understand:
On iOS, .NET does not allow dynamic type generation via reflection. This causes an issue when (the old) Newtonsoft.Json tries to instantiate an object without a parameterless constructor.

Therefore, I think I may need to use Json.NET.Aot.

However, it seems that the version of Newtonsoft.Json included in Ably conflicts with Json.NET.Aot.
I've tried this solution: https://github.com/godotengine/godot/issues/58844 without success

[sacOO7]

Wow, seems we need to do good amount of work to get ably-dotnet running on ios devices.
Btw, you can mention all of these points in godot.md as per #1294 (comment)

[sacOO7]

Actually, we had similar issues with respect to unity. So, we used Newtonsoft DLL's that support AOT.
Maybe, you can try installing https://docs.unity3d.com/Packages/com.unity.nuget.newtonsoft-json@3.0/manual/index.html
This is mentioned by original developer who supported AOT for Newtonsoft -> https://github.com/applejag/Newtonsoft.Json-for-Unity?tab=readme-ov-file

[sacOO7]

We can disable assembly versioning validation in unity as per => https://github.com/ably/ably-dotnet/blob/main/unity/CONTRIBUTING.md#disable-assembly-validation-error. This is to avoid dependency conflicts.
Maybe similar functionality is available in godot.

[sacOO7]

If nothing works, worst case, download all DLL's under https://github.com/ably/ably-dotnet/tree/main/unity/Assets/Ably/Plugins and reference those as a part of the godot project. Those also include newtonsoft DLLs that support AOT.

[sacOO7]

Btw, comment on the issue -> godotengine/godot#58844 (comment), should work. Since, internal newtonsoft version is 9.*. You can check -> https://www.nuget.org/packages/ably.io#dependencies-body-tab
So, you can include IO.Ably.dll, System.Runtime.CompilerServices.Unsafe.dll, System.Threading.Channels.dll and System.Threading.Tasks.Extensions.dll as per godotengine/godot#58844 (comment) and install newtonsoft as per

<PackageReference Include="Json.NET.Aot" Version="9.0.1" /> 

Including DLL for ably should look like

  <ItemGroup>
    <Reference Include="IO.Ably">
    <HintPath>$(ProjectDir)/IO.Ably.dll</HintPath>
    <Private>False</Private>
    </Reference>
  </ItemGroup>

Similarly you can include others

[sacOO7]

Hi @BriBarthelemy were you able to get update on this?

[BriBarthelemy]

Hello @sacOO7 ,

Not yet, I'll try to take time to invest more time to this.

I'll keep you posted.