Android .net6 project throw exception when serilaize Tuple in Release mode (v13.0.2)

[SPuV]

Steps

1. Need create Android project on .net6
2. Add reference to Newtonsoft.Json lib 13.0.2
3. Create simple class with Tuple and try to serialize it.

Result: Debug mode works well. Release mode will throw exception.

Code simple

var tuple = new Tuple<decimal, string>(1, "one");
var json = JsonConvert.SerializeObject(tuple, Formatting.Indented);

Actual behavior

Code in release mode will trow exception after try serialize

Newtonsoft.Json.JsonSerializationException
Newtonsoft.Json.JsonSerializationException: A member with the name '' already exists on 'System.Tuple`2[System.Decimal,System.String]'. Use the JsonPropertyAttribute to specify another name.

Newtonsoft.Json.Serialization.JsonPropertyCollection.AddProperty(JsonProperty property)
Newtonsoft.Json.Serialization.DefaultContractResolver.CreateConstructorParameters(ConstructorInfo constructor, JsonPropertyCollection memberProperties)
Newtonsoft.Json.Serialization.DefaultContractResolver.CreateObjectContract(Type objectType)
Newtonsoft.Json.Serialization.DefaultContractResolver.CreateContract(Type objectType)
System.Collections.Concurrent.ConcurrentDictionary`2[[System.Type, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[Newtonsoft.Json.Serialization.JsonContract, Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed]].GetOrAdd(Type , Func`2 )
Newtonsoft.Json.Utilities.ThreadSafeStore`2[[System.Type, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[Newtonsoft.Json.Serialization.JsonContract, Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed]].Get(Type key)
Newtonsoft.Json.Serialization.DefaultContractResolver.ResolveContract(Type type)
Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.WriteStartArray(JsonWriter writer, Object values, JsonArrayContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IEnumerable values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)
Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
Newtonsoft.Json.JsonConvert.SerializeObjectInternal(Object value, Type type, JsonSerializer jsonSerializer)
Newtonsoft.Json.JsonConvert.SerializeObject(Object value, Type type, Formatting formatting, JsonSerializerSettings settings)
Newtonsoft.Json.JsonConvert.SerializeObject(Object value, Formatting formatting, JsonSerializerSettings settings)

Expected behavior

Code will serialize in release mode without exception

[elgonzo]

Are you by any chance trimming when building in Release mode?

[SPuV]

@elgonzo Yes, I think problem is in trimming. When I add <PublishTrimmed>false</PublishTrimmed> to project file, then application works fine in release mode, but size of our application is increased from 80 Mb to 190Mb. This way is not preferred.

[elgonzo]

Then i would strongly recommend - if feasible - switching from Newtonsoft.Json to System.Text.Json, although i can't predict the success chance due to being oblivious of your project. Reflection-based serializers like Newtonsoft.Json are always a big problem regarding trimming (and native AOT compiling, for that matter), unfortunately.

[SPuV]

I don't think switching to System.Text.Json is the best solution. I prefer to use Newtonsoft.Json :)

At current moment I've fixed problem by adding System.Private.CoreLib lib to ignore list for trimming to .proj file

  <Target Name="ConfigureTrimming" BeforeTargets="PrepareForILLink">
    <ItemGroup>
      <ManagedAssemblyToLink Condition="'%(Filename)' == 'System.Private.CoreLib'">
        <IsTrimmable>false</IsTrimmable>
      </ManagedAssemblyToLink>
    </ItemGroup>
  </Target>

[michaelhannes]

Just my 5 cents, as a newish .net programmer, but lifelong programmer. I am having the same problem with a WASM client, but only when deployed to Azure Webapp.

When running locally there is no problem with retrieving a tuple that has an empty string as a parameter ( boolean, string="") - but it will throw exception only in release mode, eg. deployed as web app.

I guess my main contribution to this discussion is that it occurred in a WASM app, and not just android.

it also did not occur under .net 5 when we deployed to Azure Web App - only after migrating to .net 6 & .net 7

api Return -> Item1=true, Item2=""

failing code: var result = await _httpClient.GetFromJsonAsync<Tuple<bool, string>>(apiPath)

Result I then tried to use Newtonsoft, and System.Text.Json to deserialize json, using _httpClient.GetStringAsync(api_path),

but it always gave a problem with the empty string after publishing to azure web app. either with nullparameter, or nullname, or something like that. i can resetup environment if needed.

hope that helps