Set ModelMetadata when given response type for attribute

Author: halter73

src/Mvc/Mvc.ApiExplorer/src/ApiResponseTypeProvider.cs

@@ -159,7 +159,6 @@ internal static List<ApiResponseType> ReadResponseMetadata(
 
                     if (apiResponseType.Type != null)
                     {
-                        AddApiResponseFormats(apiResponseType.ApiResponseFormats, contentTypes);
                         results[apiResponseType.StatusCode] = apiResponseType;
                     }
                 }
@@ -168,17 +167,6 @@ internal static List<ApiResponseType> ReadResponseMetadata(
             return results.Values.ToList();
         }
 
-        internal static void AddApiResponseFormats(IList<ApiResponseFormat> apiResponseFormats, IReadOnlyList<string> contentTypes)
-        {
-            foreach (var contentType in contentTypes)
-            {
-                apiResponseFormats.Add(new ApiResponseFormat
-                {
-                    MediaType = contentType,
-                });
-            }
-        }
-
         private void CalculateResponseFormats(ICollection<ApiResponseType> responseTypes, MediaTypeCollection declaredContentTypes)
         {
             var responseTypeMetadataProviders = _mvcOptions.OutputFormatters.OfType<IApiResponseTypeMetadataProvider>();
@@ -194,9 +182,6 @@ private void CalculateResponseFormats(ICollection<ApiResponseType> responseTypes
 
             foreach (var apiResponse in responseTypes)
             {
-                // ApiResponseFormats has been preset for EndpointMetadataApiDescriptionProvider's use but MVC has more inputs to consider.
-                apiResponse.ApiResponseFormats.Clear();
-
                 var responseType = apiResponse.Type;
                 if (responseType == null || responseType == typeof(void))
                 {

src/Mvc/Mvc.ApiExplorer/src/EndpointMetadataApiDescriptionProvider.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Reflection;
 using System.Threading;
@@ -106,7 +107,7 @@ private static ApiParameterDescription CreateApiParameterDescription(ParameterIn
             return new ApiParameterDescription
             {
                 Name = name,
-                ModelMetadata = new EndpointModelMetadata(ModelMetadataIdentity.ForType(parameter.ParameterType)),
+                ModelMetadata = CreateModelMetadata(parameter.ParameterType),
                 Source = source,
                 DefaultValue = parameter.DefaultValue,
             };
@@ -185,8 +186,15 @@ private static void AddSupportedResponseTypes(IList<ApiResponseType> supportedRe
             {
                 foreach (var apiResponseType in responseMetadataTypes)
                 {
-                    if (apiResponseType.ApiResponseFormats.Count == 0 &&
-                        CreateDefaultApiResponseFormat(responseType) is { } defaultResponseFormat)
+                    Debug.Assert(apiResponseType.Type is not null, "ApiResponseTypeProvider gave us a null Type!?");
+
+                    apiResponseType.ModelMetadata = CreateModelMetadata(apiResponseType.Type);
+
+                    if (contentTypes.Count > 0)
+                    {
+                        AddResponseContentTypes(apiResponseType.ApiResponseFormats, contentTypes);
+                    }
+                    else if (CreateDefaultApiResponseFormat(responseType) is { } defaultResponseFormat)
                     {
                         apiResponseType.ApiResponseFormats.Add(defaultResponseFormat);
                     }
@@ -203,7 +211,7 @@ private static void AddSupportedResponseTypes(IList<ApiResponseType> supportedRe
                 {
                     // If metadata provided us with response formats, use that instead of the default.
                     defaultApiResponseType.ApiResponseFormats.Clear();
-                    ApiResponseTypeProvider.AddApiResponseFormats(defaultApiResponseType.ApiResponseFormats, contentTypes);
+                    AddResponseContentTypes(defaultApiResponseType.ApiResponseFormats, contentTypes);
                 }
 
                 supportedResponseTypes.Add(defaultApiResponseType);
@@ -214,7 +222,7 @@ private static ApiResponseType CreateDefaultApiResponseType(Type responseType)
         {
             var apiResponseType = new ApiResponseType
             {
-                ModelMetadata = new EndpointModelMetadata(ModelMetadataIdentity.ForType(responseType)),
+                ModelMetadata = CreateModelMetadata(responseType),
                 StatusCode = 200,
             };
 
@@ -244,5 +252,19 @@ private static ApiResponseType CreateDefaultApiResponseType(Type responseType)
                 return new ApiResponseFormat { MediaType = "application/json" };
             }
         }
+
+        private static EndpointModelMetadata CreateModelMetadata(Type type) =>
+            new EndpointModelMetadata(ModelMetadataIdentity.ForType(type));
+
+        private static void AddResponseContentTypes(IList<ApiResponseFormat> apiResponseFormats, IReadOnlyList<string> contentTypes)
+        {
+            foreach (var contentType in contentTypes)
+            {
+                apiResponseFormats.Add(new ApiResponseFormat
+                {
+                    MediaType = contentType,
+                });
+            }
+        }
     }
 }

src/Mvc/Mvc.ApiExplorer/test/EndpointMethodInfoApiDescriptionProviderTest.cs renamed to src/Mvc/Mvc.ApiExplorer/test/EndpointMetadataApiDescriptionProviderTest.cs

@@ -13,7 +13,7 @@
 
 namespace Microsoft.AspNetCore.Mvc.ApiExplorer
 {
-    public class EndpointMethodInfoApiDescriptionProviderTest
+    public class EndpointMetadataApiDescriptionProviderTest
     {
         [Fact]
         public void ApiDescription_MultipleCreatedForMultipleHttpMethods()