Fix UseProjection with JsonDocument nested field selection

src/HotChocolate/Data/src/Data/Projections/Expressions/Handlers/QueryableProjectionFieldHandler.cs

@@ -69,8 +69,6 @@ public override bool TryHandleLeave(
             return false;
         }
 
-        var memberInit = queryableScope.CreateMemberInit();
-
         if (!context.TryGetQueryableScope(out var parentScope))
         {
             throw ThrowHelper.ProjectionVisitor_InvalidState_NoParentScope();
@@ -88,6 +86,21 @@ public override bool TryHandleLeave(
             return true;
         }
 
+        // If the nested scope has no projectable members we keep the original value.
+        // This happens for members like JsonDocument where selected subfields are read-only.
+        if (!queryableScope.HasAbstractTypes() && queryableScope.Level.Peek().Count == 0)
+        {
+            parentScope.Level
+                .Peek()
+                .Enqueue(Expression.Bind(field.Member, nestedProperty));
+
+            action = SelectionVisitor.Continue;
+
+            return true;
+        }
+
+        var memberInit = queryableScope.CreateMemberInit();
+
         if (context.InMemory)
         {
             parentScope.Level

src/HotChocolate/Data/test/Data.Tests/Issue5893Tests.cs

@@ -0,0 +1,55 @@
+using System.Text.Json;
+using HotChocolate.Execution;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace HotChocolate.Data;
+
+public class Issue5893Tests
+{
+    [Fact]
+    public async Task UseProjection_With_JsonDocument_Should_Not_Error()
+    {
+        var executor = await new ServiceCollection()
+            .AddGraphQLServer()
+            .AddProjections()
+            .AddQueryType<Issue5893Query>()
+            .BuildRequestExecutorAsync();
+
+        var result = await executor.ExecuteAsync(
+            """
+            {
+              tests {
+                codigo
+                data {
+                  rootElement
+                }
+              }
+            }
+            """);
+
+        var operationResult = result.ExpectOperationResult();
+        Assert.Empty(operationResult.Errors ?? []);
+    }
+
+    public sealed class Issue5893Query
+    {
+        [UseProjection]
+        public IQueryable<Issue5893Model> GetTests()
+            => new[]
+                {
+                    new Issue5893Model
+                    {
+                        Codigo = "a",
+                        Data = JsonDocument.Parse("""{"a":1}""")
+                    }
+                }
+                .AsQueryable();
+    }
+
+    public sealed class Issue5893Model
+    {
+        public string Codigo { get; set; } = string.Empty;
+
+        public JsonDocument? Data { get; set; }
+    }
+}