Changing IsPolymorphicSafe

Author: brunolins16

src/Http/Http.Extensions/src/RequestDelegateFactory.cs

@@ -1055,7 +1055,7 @@ private static Expression AddResponseWritingToMethodCall(Expression methodCall,
                 {
                     var jsonTypeInfo = factoryContext.JsonSerializerOptions.GetReadOnlyTypeInfo(typeArg);
 
-                    if (jsonTypeInfo.IsPolymorphicSafe() == true)
+                    if (jsonTypeInfo.HasKnownPolymorphism())
                     {
                         return Expression.Call(
                             ExecuteTaskOfTFastMethod.MakeGenericMethod(typeArg),
@@ -1096,7 +1096,7 @@ private static Expression AddResponseWritingToMethodCall(Expression methodCall,
                 {
                     var jsonTypeInfo = factoryContext.JsonSerializerOptions.GetReadOnlyTypeInfo(typeArg);
 
-                    if (jsonTypeInfo.IsPolymorphicSafe() == true)
+                    if (jsonTypeInfo.HasKnownPolymorphism())
                     {
                         return Expression.Call(
                             ExecuteValueTaskOfTFastMethod.MakeGenericMethod(typeArg),
@@ -1140,7 +1140,7 @@ private static Expression AddResponseWritingToMethodCall(Expression methodCall,
         {
             var jsonTypeInfo = factoryContext.JsonSerializerOptions.GetReadOnlyTypeInfo(returnType);
 
-            if (jsonTypeInfo.IsPolymorphicSafe() == true)
+            if (jsonTypeInfo.HasKnownPolymorphism())
             {
                 return Expression.Call(
                     JsonResultWriteResponseOfTFastAsyncMethod.MakeGenericMethod(returnType),

src/Http/Http.Results/src/HttpResultsHelper.cs

@@ -35,7 +35,7 @@ public static Task WriteResultAsJsonAsync<TValue>(
         var jsonTypeInfo = (JsonTypeInfo<TValue>)jsonSerializerOptions.GetTypeInfo(typeof(TValue));
 
         Type? runtimeType;
-        if (jsonTypeInfo.IsPolymorphicSafe() || jsonTypeInfo.Type == (runtimeType = value.GetType()))
+        if (jsonTypeInfo.IsValid(runtimeType = value.GetType()))
         {
             Log.WritingResultAsJson(logger, jsonTypeInfo.Type.Name);
             return httpContext.Response.WriteAsJsonAsync(

src/Mvc/Mvc.Core/src/Formatters/SystemTextJsonOutputFormatter.cs

@@ -72,7 +72,7 @@ public sealed override async Task WriteResponseBodyAsync(OutputFormatterWriteCon
         {
             var declaredTypeJsonInfo = SerializerOptions.GetTypeInfo(context.ObjectType);
 
-            if (declaredTypeJsonInfo.IsPolymorphicSafe() || context.Object is null || runtimeType == declaredTypeJsonInfo.Type)
+            if (declaredTypeJsonInfo.IsValid(runtimeType))
             {
                 jsonTypeInfo = declaredTypeJsonInfo;
             }

src/Shared/Json/JsonSerializerExtensions.cs

@@ -9,9 +9,12 @@ namespace Microsoft.AspNetCore.Http;
 
 internal static class JsonSerializerExtensions
 {
-    public static bool IsPolymorphicSafe(this JsonTypeInfo jsonTypeInfo)
+    public static bool HasKnownPolymorphism(this JsonTypeInfo jsonTypeInfo)
      => jsonTypeInfo.Type.IsSealed || jsonTypeInfo.Type.IsValueType || jsonTypeInfo.PolymorphismOptions is not null;
 
+    public static bool IsValid(this JsonTypeInfo jsonTypeInfo, Type? runtimeType)
+     => runtimeType is null || jsonTypeInfo.Type == runtimeType || jsonTypeInfo.HasKnownPolymorphism();
+
     public static JsonTypeInfo GetReadOnlyTypeInfo(this JsonSerializerOptions options, Type type)
     {
         options.MakeReadOnly();

src/Shared/RouteHandlers/ExecuteHandlerHelper.cs

@@ -37,7 +37,7 @@ public static Task WriteJsonResponseAsync<T>(HttpResponse response, T? value, Js
     {
         var runtimeType = value?.GetType();
 
-        if (runtimeType is null || jsonTypeInfo.Type == runtimeType || jsonTypeInfo.IsPolymorphicSafe())
+        if (jsonTypeInfo.IsValid(runtimeType))
         {
             // In this case the polymorphism is not
             // relevant for us and will be handled by STJ, if needed.