Deserialization error in XCode for iOS build: MissingMethodException

[markcbaumann]

I am using Unity version 2017.2.0f3 with Newtonsoft.Json

I am trying to deserialize in an iOS build. The error happens in the Deserialize call here:

    JsonSerializer serializer = new JsonSerializer();
    serializer.Converters.Add(new ConditionalConverter());
    serializer.Converters.Add(new StringEnumConverter());
    serializer.Converters.Add(new VariableConverter());

    using (var jsonReader = new JsonTextReader(new StringReader(jsonFile.text)))
    {
        myStory = serializer.Deserialize<Story>(jsonReader);
    }

This code works fine when I run it inside Unity. However when I make an iOS build and run that build in XCode, I get the following error:

MissingMethodException: Constructor on type 'System.ComponentModel.ReferenceConverter' not found. at System.RuntimeType.CreateInstanceImpl (System.Reflection.BindingFlags bindingAttr, System.Reflection.Binder binder, System.Object[] args, System.Globalization.CultureInfo culture, System.Object[] activationAttributes, System.Threading.StackCrawlMark& stackMark) [0x00000] in <00000000000000000000000000000000>:0 at System.Activator.CreateInstance (System.Type type, System.Reflection.BindingFlags bindingAttr, System.Reflection.Binder binder, System.Object[] args, System.Globalization.CultureInfo culture, System.Object[] activationAttributes) [0x00000] in <00000000000000000000000000000000>:0 at System.Activator.CreateInstance (System.Type type, System.Reflection.BindingFlags bindingAttr, System.Reflection.Binder binder, System.Object[] args, System.Globalization.CultureInfo culture) [0x00000] in <00000000000000000000000000000000>:0 at System.SecurityUtils.SecureCreateInstance (System.Type type, System.Object[] args, System.Boolean allowNonPublic) [0x00000] in <00000000000000000000000000000000>:0 at System.SecurityUtils.SecureCreateInstance (System.Type type) [0x00000] in <00000000000000000000000000000000>:0 at System.ComponentModel.ReflectTypeDescriptionProvider.SearchIntrinsicTable (System.Collections.Hashtable table, System.Type callingType) [0x00000] in <00000000000000000000000000000000>:0 at System.ComponentModel.ReflectTypeDescriptionProvider+ReflectedTypeData.GetConverter (System.Object instance) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.DefaultContractResolver.CanConvertToString (System.Type type) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.DefaultContractResolver.CreateContract (System.Type objectType) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.DefaultContractResolver.ResolveContract (System.Type type) [0x00000] in <00000000000000000000000000000000>:0

at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateDictionary (System.Collections.IDictionary dictionary, Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonDictionaryContract contract, Newtonsoft.Json.Serialization.JsonProperty containerProperty, System.String id) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue (Newtonsoft.Json.Serialization.JsonProperty property, Newtonsoft.Json.JsonConverter propertyConverter, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty, Newtonsoft.Json.JsonReader reader, System.Object target) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject (System.Object newObject, Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonObjectContract contract, Newtonsoft.Json.Serialization.JsonProperty member, System.String id) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, System.Object existingValue) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, System.Boolean checkAdditionalContent) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType) [0x00000] in <00000000000000000000000000000000>:0 at Newtonsoft.Json.JsonSerializer.Deserialize[T] (Newtonsoft.Json.JsonReader reader) [0x00000] in <00000000000000000000000000000000>:0 at ViewController.Start () [0x00000] in <00000000000000000000000000000000>:0

[markcbaumann]

I found a fix. I modified the contents of my link.xml file to be:

<linker>
  <assembly fullname="System">
    <namespace fullname="System.ComponentModel" preserve="all" />
  </assembly>
</linker>

This is the link.xml file that is found in your Unity project in the folder JsonDotNet.