From 2e3590ddf128994e488d94808fd03b5e85dff42d Mon Sep 17 00:00:00 2001
From: David Driscoll <david.driscoll@gmail.com>
Date: Sat, 11 Nov 2023 04:37:26 -0500
Subject: [PATCH] Fixed Utf8JsonWriterHelper to not ignore null dictionary
 values (#6689)

---
 .../Serialization/Utf8JsonWriterHelper.cs     |  5 ---
 .../OperationRequestTests.cs                  | 37 +++++++++++++++++++
 2 files changed, 37 insertions(+), 5 deletions(-)
 create mode 100644 src/HotChocolate/AspNetCore/test/Transport.Http.Tests/OperationRequestTests.cs

diff --git a/src/HotChocolate/AspNetCore/src/Transport.Abstractions/Serialization/Utf8JsonWriterHelper.cs b/src/HotChocolate/AspNetCore/src/Transport.Abstractions/Serialization/Utf8JsonWriterHelper.cs
index 484e509c578..ef7035838c2 100644
--- a/src/HotChocolate/AspNetCore/src/Transport.Abstractions/Serialization/Utf8JsonWriterHelper.cs
+++ b/src/HotChocolate/AspNetCore/src/Transport.Abstractions/Serialization/Utf8JsonWriterHelper.cs
@@ -194,11 +194,6 @@ private static void WriteDictionary(
 
         foreach (var item in dict)
         {
-            if (item.Value is null)
-            {
-                continue;
-            }
-
             writer.WritePropertyName(item.Key);
             WriteFieldValue(writer, item.Value);
         }
diff --git a/src/HotChocolate/AspNetCore/test/Transport.Http.Tests/OperationRequestTests.cs b/src/HotChocolate/AspNetCore/test/Transport.Http.Tests/OperationRequestTests.cs
new file mode 100644
index 00000000000..ed07f32ab1a
--- /dev/null
+++ b/src/HotChocolate/AspNetCore/test/Transport.Http.Tests/OperationRequestTests.cs
@@ -0,0 +1,37 @@
+using System.Text;
+using System.Text.Json;
+using CookieCrumble;
+using Moq;
+
+namespace HotChocolate.Transport.Http.Tests;
+
+public class OperationRequestTests
+{
+    [Fact]
+    public async Task Should_WriteNullValues()
+    {
+        // arrange
+        var request = new OperationRequest(
+            null,
+            "abc",
+            "myOperation",
+            variables: new Dictionary<string, object?>()
+            {
+                ["abc"] = "def",
+                ["hij"] = null
+            });
+
+        using var memory = new MemoryStream();
+        await using var writer = new Utf8JsonWriter(memory);
+
+        // act
+        request.WriteTo(writer);
+        await writer.FlushAsync();
+
+        // assert
+        var result = Encoding.UTF8.GetString(memory.ToArray());
+        Assert.Equal(
+            """{"id":"abc","operationName":"myOperation","variables":{"abc":"def","hij":null}}""",
+            result);
+    }
+}