Media type application/problem+json lost in combination with ProducesAttribute #19510 (#30367)

* fix and test case added

* fix

* Apply suggestions from code review

Co-authored-by: Pranav K <[email protected]>

Author: kishanAnem

src/Mvc/Mvc.Core/src/Infrastructure/ObjectResultExecutor.cs

@@ -151,19 +151,16 @@ private Task ExecuteAsyncCore(ActionContext context, ObjectResult result, Type?
         private static void InferContentTypes(ActionContext context, ObjectResult result)
         {
             Debug.Assert(result.ContentTypes != null);
-            if (result.ContentTypes.Count != 0)
-            {
-                return;
-            }
 
             // If the user sets the content type both on the ObjectResult (example: by Produces) and Response object,
             // then the one set on ObjectResult takes precedence over the Response object
             var responseContentType = context.HttpContext.Response.ContentType;
-            if (!string.IsNullOrEmpty(responseContentType))
+            if (result.ContentTypes.Count == 0 && !string.IsNullOrEmpty(responseContentType))
             {
                 result.ContentTypes.Add(responseContentType);
             }
-            else if (result.Value is ProblemDetails)
+            
+            if (result.Value is ProblemDetails)
             {
                 result.ContentTypes.Add("application/problem+json");
                 result.ContentTypes.Add("application/problem+xml");

src/Mvc/Mvc.Core/test/Infrastructure/ObjectResultExecutorTest.cs

@@ -114,50 +114,123 @@ public async Task ExecuteAsync_WithOneProvidedContentType_FromResponseContentTyp
         }
 
         [Fact]
-        public async Task ExecuteAsync_ForProblemDetailsValue_UsesSpecifiedContentType()
+        public async Task ExecuteAsync_WithResponseAndObjectResultContentType_ForProblemDetailsValue_UsesXMLContentType()
         {
             // Arrange
             var executor = CreateExecutor();
 
             var httpContext = new DefaultHttpContext();
             var actionContext = new ActionContext() { HttpContext = httpContext };
-            httpContext.Response.ContentType = "application/json";
+            httpContext.Response.ContentType = "application/xml"; // This will not be used
 
             var result = new ObjectResult(new ProblemDetails())
             {
-                ContentTypes = { "text/plain" },
+                ContentTypes = { "text/plain" }, // This will not be used
             };
-            result.Formatters.Add(new TestXmlOutputFormatter());
+            result.Formatters.Add(new TestXmlOutputFormatter());  // This will be chosen based on the problem details content type
             result.Formatters.Add(new TestJsonOutputFormatter());
-            result.Formatters.Add(new TestStringOutputFormatter()); // This will be chosen based on the content type
+            result.Formatters.Add(new TestStringOutputFormatter());
 
             // Act
             await executor.ExecuteAsync(actionContext, result);
 
             // Assert
-            MediaTypeAssert.Equal("text/plain; charset=utf-8", httpContext.Response.ContentType);
+            MediaTypeAssert.Equal("application/problem+xml; charset=utf-8", httpContext.Response.ContentType);
         }
 
         [Fact]
-        public async Task ExecuteAsync_ForProblemDetailsValue_UsesResponseContentType()
+        public async Task ExecuteAsync_WithResponseContentType_ForProblemDetailsValue_UsesProblemDetailXMLContentType()
         {
             // Arrange
             var executor = CreateExecutor();
 
             var httpContext = new DefaultHttpContext();
             var actionContext = new ActionContext() { HttpContext = httpContext };
-            httpContext.Response.ContentType = "application/json";
+            httpContext.Response.ContentType = "application/json"; // This will not be used
 
             var result = new ObjectResult(new ProblemDetails());
+            result.Formatters.Add(new TestXmlOutputFormatter()); // This will be chosen based on the problem details content type            
+            result.Formatters.Add(new TestJsonOutputFormatter());
+            result.Formatters.Add(new TestStringOutputFormatter());
+
+            // Act
+            await executor.ExecuteAsync(actionContext, result);
+
+            // Assert
+            MediaTypeAssert.Equal("application/problem+xml; charset=utf-8", httpContext.Response.ContentType);
+        }
+
+        [Fact]
+        public async Task ExecuteAsync_ForProblemDetailsValue_UsesProblemDetailsContentType()
+        {
+            // Arrange
+            var executor = CreateExecutor();
+
+            var httpContext = new DefaultHttpContext();
+            var actionContext = new ActionContext() { HttpContext = httpContext };
+            httpContext.Response.ContentType = "application/json"; // This will not be used
+
+            var result = new ObjectResult(new ProblemDetails());
+            result.Formatters.Add(new TestXmlOutputFormatter()); // This will be chosen based on the problem details content type            
+            result.Formatters.Add(new TestJsonOutputFormatter());
+            result.Formatters.Add(new TestStringOutputFormatter());
+
+            // Act
+            await executor.ExecuteAsync(actionContext, result);
+
+            // Assert
+            MediaTypeAssert.Equal("application/problem+xml; charset=utf-8", httpContext.Response.ContentType);
+        }
+
+        [Fact]
+        public async Task ExecuteAsync_ForProblemDetailsValue_UsesProblemDetailsJsonContentType_BasedOnAcceptHeader()
+        {
+            // Arrange
+            var executor = CreateExecutor();
+
+            var httpContext = new DefaultHttpContext();
+            var actionContext = new ActionContext() { HttpContext = httpContext };
+            httpContext.Request.Headers[HeaderNames.Accept] = "application/json"; // This will not be used
+            httpContext.Response.ContentType = "application/xml"; // This will not be used
+
+            var result = new ObjectResult(new ProblemDetails())
+            {
+                ContentTypes = { "text/plain" }, // This will not be used
+            }; 
+            result.Formatters.Add(new TestJsonOutputFormatter()); // This will be chosen based on the Accept Headers "application/json"
             result.Formatters.Add(new TestXmlOutputFormatter());
-            result.Formatters.Add(new TestJsonOutputFormatter());  // This will be chosen based on the response content type
             result.Formatters.Add(new TestStringOutputFormatter());
 
             // Act
             await executor.ExecuteAsync(actionContext, result);
 
             // Assert
-            MediaTypeAssert.Equal("application/json; charset=utf-8", httpContext.Response.ContentType);
+            MediaTypeAssert.Equal("application/problem+json; charset=utf-8", httpContext.Response.ContentType);
+        }
+        
+        [Fact]
+        public async Task ExecuteAsync_ForProblemDetailsValue_UsesProblemDetailsXMLContentType_BasedOnAcceptHeader()
+        {
+            // Arrange
+            var executor = CreateExecutor();
+
+            var httpContext = new DefaultHttpContext();
+            var actionContext = new ActionContext() { HttpContext = httpContext };
+            httpContext.Request.Headers[HeaderNames.Accept] = "application/xml"; // This will not be used
+
+            var result = new ObjectResult(new ProblemDetails())
+            {
+                ContentTypes = { "text/plain" }, // This will not be used
+            }; 
+            result.Formatters.Add(new TestJsonOutputFormatter()); 
+            result.Formatters.Add(new TestXmlOutputFormatter()); // This will be chosen based on the Accept Headers "application/xml"
+            result.Formatters.Add(new TestStringOutputFormatter());
+
+            // Act
+            await executor.ExecuteAsync(actionContext, result);
+
+            // Assert
+            MediaTypeAssert.Equal("application/problem+xml; charset=utf-8", httpContext.Response.ContentType);
         }
 
         [Fact]
@@ -170,7 +243,7 @@ public async Task ExecuteAsync_NoContentTypeProvidedForProblemDetails_UsesDefaul
             var actionContext = new ActionContext() { HttpContext = httpContext };
 
             var result = new ObjectResult(new ProblemDetails());
-            result.Formatters.Add(new TestXmlOutputFormatter());  // This will be chosen based on the implicitly added content type
+            result.Formatters.Add(new TestXmlOutputFormatter());  // This will be chosen based on the problem details added content type
             result.Formatters.Add(new TestJsonOutputFormatter());
             result.Formatters.Add(new TestStringOutputFormatter());