feat: Make common sdk AOT safe

pkgs/shared/common/src/Context.cs

@@ -922,7 +922,11 @@ public override string ToString()
             {
                 return "(invalid Context: " + Error + ")";
             }
+#if NET7_0_OR_GREATER
+            return System.Text.Json.JsonSerializer.Serialize(this, LdJsonSerializerContext.Default.Context);
+#else
             return LdJsonSerialization.SerializeObject(this);
+#endif
         }
 
         private LdValue GetTopLevelAddressableAttributeSingleKind(string name)

pkgs/shared/common/src/Json/LdJsonConverters.cs

@@ -196,7 +196,13 @@ public static void WriteJsonValue(BigSegmentsStatus instance, Utf8JsonWriter wri
 
             internal static BigSegmentsStatus FromIdentifier(string value)
             {
-                foreach (BigSegmentsStatus k in Enum.GetValues(typeof(BigSegmentsStatus)))
+                foreach (BigSegmentsStatus k in
+#if NET5_0_OR_GREATER
+                    Enum.GetValues<BigSegmentsStatus>()
+#else
+                    Enum.GetValues(typeof(BigSegmentsStatus))
+#endif
+                )
                 {
                     if (ToIdentifier(k) == value)
                     {
@@ -243,7 +249,13 @@ public static void WriteJsonValue(EvaluationErrorKind instance, Utf8JsonWriter w
 
             internal static EvaluationErrorKind FromIdentifier(string value)
             {
-                foreach (EvaluationErrorKind k in Enum.GetValues(typeof(EvaluationErrorKind)))
+                foreach (EvaluationErrorKind k in
+#if NET5_0_OR_GREATER
+                    Enum.GetValues<EvaluationErrorKind>()
+#else
+                    Enum.GetValues(typeof(EvaluationErrorKind))
+#endif
+                )
                 {
                     if (ToIdentifier(k) == value)
                     {
@@ -294,7 +306,13 @@ public void WriteJsonValue(EvaluationReasonKind instance, Utf8JsonWriter writer)
 
             internal static EvaluationReasonKind FromIdentifier(string value)
             {
-                foreach (EvaluationReasonKind k in Enum.GetValues(typeof(EvaluationErrorKind)))
+                foreach (EvaluationReasonKind k in
+#if NET5_0_OR_GREATER
+                    Enum.GetValues<EvaluationReasonKind>()
+#else
+                    Enum.GetValues(typeof(EvaluationErrorKind))
+#endif
+                )
                 {
                     if (ToIdentifier(k) == value)
                     {

pkgs/shared/common/src/Json/LdJsonSerialization.cs

@@ -1,5 +1,8 @@
 using System;
 using System.Text.Json;
+#if NET7_0_OR_GREATER
+using System.Diagnostics.CodeAnalysis;
+#endif
 
 namespace LaunchDarkly.Sdk.Json
 {
@@ -12,6 +15,10 @@ namespace LaunchDarkly.Sdk.Json
     /// </remarks>
     public static class LdJsonSerialization
     {
+#if NET7_0_OR_GREATER
+        internal const string SerializationUnreferencedCodeMessage = "JSON serialization and deserialization might require types that cannot be statically analyzed. Use the overload that takes a JsonTypeInfo or JsonSerializerContext, or make sure all of the required types are preserved.";
+        internal const string SerializationRequiresDynamicCodeMessage = "JSON serialization and deserialization might require types that cannot be statically analyzed and might need runtime code generation. Use System.Text.Json source generation for native AOT applications.";
+#endif  
         /// <summary>
         /// Converts an object to its JSON representation.
         /// </summary>
@@ -23,6 +30,10 @@ public static class LdJsonSerialization
         /// <typeparam name="T">type of the object being serialized</typeparam>
         /// <param name="instance">the instance to serialize</param>
         /// <returns>the object's JSON encoding as a string</returns>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode(SerializationUnreferencedCodeMessage)]
+        [RequiresDynamicCode(SerializationRequiresDynamicCodeMessage)]
+#endif
         public static string SerializeObject<T>(T instance) where T : IJsonSerializable =>
             JsonSerializer.Serialize(instance);
 
@@ -37,6 +48,10 @@ public static string SerializeObject<T>(T instance) where T : IJsonSerializable
         /// <typeparam name="T">type of the object being serialized</typeparam>
         /// <param name="instance">the instance to serialize</param>
         /// <returns>the object's JSON encoding as a byte array</returns>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode(SerializationUnreferencedCodeMessage)]
+        [RequiresDynamicCode(SerializationRequiresDynamicCodeMessage)]
+#endif
         public static byte[] SerializeObjectToUtf8Bytes<T>(T instance) where T : IJsonSerializable =>
             JsonSerializer.SerializeToUtf8Bytes(instance);
 
@@ -52,6 +67,10 @@ public static byte[] SerializeObjectToUtf8Bytes<T>(T instance) where T : IJsonSe
         /// <param name="json">the object's JSON encoding as a string</param>
         /// <returns>the deserialized instance</returns>
         /// <exception cref="JsonException">if the JSON encoding was invalid</exception>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode(SerializationUnreferencedCodeMessage)]
+        [RequiresDynamicCode(SerializationRequiresDynamicCodeMessage)]
+#endif
         public static T DeserializeObject<T>(string json) where T : IJsonSerializable =>
             JsonSerializer.Deserialize<T>(json);
     }

pkgs/shared/common/src/Json/LdJsonSerializerContext.cs

@@ -0,0 +1,13 @@
+#if NET7_0_OR_GREATER
+using System.Text.Json.Serialization;
+
+namespace LaunchDarkly.Sdk.Json
+{
+    [JsonSerializable(typeof(LdValue))]
+    [JsonSerializable(typeof(Context))]
+    internal partial class LdJsonSerializerContext : JsonSerializerContext
+    {
+
+    }
+}
+#endif

pkgs/shared/common/src/LaunchDarkly.CommonSdk.csproj

@@ -13,6 +13,8 @@
     <AssemblyName>LaunchDarkly.CommonSdk</AssemblyName>
     <OutputType>Library</OutputType>
     <LangVersion>7.3</LangVersion>
+    <!-- the system.text.json source generator require version 9.0 or greater -->
+    <LangVersion Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">9.0</LangVersion>
     <PackageId>LaunchDarkly.CommonSdk</PackageId>
     <Description>LaunchDarkly common code for .NET and Xamarin clients</Description>
     <Company>LaunchDarkly</Company>
@@ -34,6 +36,7 @@
 
     <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\LaunchDarkly.CommonSdk.xml</DocumentationFile>
     <RootNamespace>LaunchDarkly.Sdk</RootNamespace>
+    <IsAotCompatible Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">true</IsAotCompatible>
   </PropertyGroup>
 
   <ItemGroup>

pkgs/shared/common/src/LdValue.cs

@@ -282,8 +282,11 @@ public static ObjectBuilder BuildObject() =>
         /// <exception cref="JsonException">if the string could not be parsed as JSON</exception>
         /// <see cref="ToJsonString"/>
         public static LdValue Parse(string jsonString) =>
+#if NET7_0_OR_GREATER
+            JsonSerializer.Deserialize(jsonString, LdJsonSerializerContext.Default.LdValue);
+#else
             LdJsonSerialization.DeserializeObject<LdValue>(jsonString);
-
+#endif
         #endregion
 
         #region Public properties
@@ -550,7 +553,11 @@ public string ToJsonString()
                 case LdValueType.Bool:
                     return _boolValue ? "true" : "false";
                 default:
+#if NET7_0_OR_GREATER
+                    return JsonSerializer.Serialize(this, LdJsonSerializerContext.Default.LdValue);
+#else
                     return JsonSerializer.Serialize(this);
+#endif
             }
         }