Don't set StatusCode in WriteAsJsonAsync (#23583)

src/Http/Http.Extensions/src/HttpResponseJsonExtensions.cs

@@ -77,7 +77,6 @@ namespace Microsoft.AspNetCore.Http.Json
             options ??= ResolveSerializerOptions(response.HttpContext);
 
             response.ContentType = contentType ?? JsonConstants.JsonContentTypeWithCharset;
-            response.StatusCode = StatusCodes.Status200OK;
             return JsonSerializer.SerializeAsync<TValue>(response.Body, value!, options, cancellationToken);
         }
 
@@ -150,7 +149,6 @@ namespace Microsoft.AspNetCore.Http.Json
             options ??= ResolveSerializerOptions(response.HttpContext);
 
             response.ContentType = contentType ?? JsonConstants.JsonContentTypeWithCharset;
-            response.StatusCode = StatusCodes.Status200OK;
             return JsonSerializer.SerializeAsync(response.Body, value, type, options, cancellationToken);
         }
 

src/Http/Http.Extensions/test/HttpResponseJsonExtensionsTests.cs

@@ -88,6 +88,23 @@ namespace Microsoft.AspNetCore.Http.Extensions.Tests
             }
         }
 
+        [Fact]
+        public async Task WriteAsJsonAsyncGeneric_CustomStatusCode_StatusCodeUnchanged()
+        {
+            // Arrange
+            var body = new MemoryStream();
+            var context = new DefaultHttpContext();
+            context.Response.Body = body;
+
+            // Act
+            context.Response.StatusCode = StatusCodes.Status418ImATeapot;
+            await context.Response.WriteAsJsonAsync(1);
+
+            // Assert
+            Assert.Equal(JsonConstants.JsonContentTypeWithCharset, context.Response.ContentType);
+            Assert.Equal(StatusCodes.Status418ImATeapot, context.Response.StatusCode);
+        }
+
         [Fact]
         public async Task WriteAsJsonAsyncGeneric_WithContentType_JsonResponseWithCustomContentType()
         {
@@ -223,6 +240,23 @@ namespace Microsoft.AspNetCore.Http.Extensions.Tests
             Assert.Equal(@"{""stringProperty"":""激光這兩個字是甚麼意思""}", data);
         }
 
+        [Fact]
+        public async Task WriteAsJsonAsync_CustomStatusCode_StatusCodeUnchanged()
+        {
+            // Arrange
+            var body = new MemoryStream();
+            var context = new DefaultHttpContext();
+            context.Response.Body = body;
+
+            // Act
+            context.Response.StatusCode = StatusCodes.Status418ImATeapot;
+            await context.Response.WriteAsJsonAsync(1, typeof(int));
+
+            // Assert
+            Assert.Equal(JsonConstants.JsonContentTypeWithCharset, context.Response.ContentType);
+            Assert.Equal(StatusCodes.Status418ImATeapot, context.Response.StatusCode);
+        }
+
         public class TestObject
         {
             public string? StringProperty { get; set; }