From 3674888ce1e9b6de4c41fc6bbecbd7fc698de369 Mon Sep 17 00:00:00 2001
From: Maksim Bronnikov <maksim.bronnikov@mail.ru>
Date: Mon, 15 Dec 2025 19:49:07 +0300
Subject: [PATCH] Fix WSDL schema generator with non-annotated System.Object
 (backcompatibility with wcf?)

---
 .../Services/ComplexTypeWithSystemObject.cs   |  6 ++++++
 .../IComplexTypeWithSystemObjectService.cs    | 17 +++++++++++++++++
 src/SoapCore.Tests/Wsdl/WsdlTests.cs          | 19 +++++++++++++++++++
 src/SoapCore/Meta/MetaBodyWriter.cs           |  5 +++++
 4 files changed, 47 insertions(+)
 create mode 100644 src/SoapCore.Tests/Wsdl/Services/ComplexTypeWithSystemObject.cs
 create mode 100644 src/SoapCore.Tests/Wsdl/Services/IComplexTypeWithSystemObjectService.cs

diff --git a/src/SoapCore.Tests/Wsdl/Services/ComplexTypeWithSystemObject.cs b/src/SoapCore.Tests/Wsdl/Services/ComplexTypeWithSystemObject.cs
new file mode 100644
index 00000000..22555242
--- /dev/null
+++ b/src/SoapCore.Tests/Wsdl/Services/ComplexTypeWithSystemObject.cs
@@ -0,0 +1,6 @@
+namespace SoapCore.Tests.Wsdl.Services;
+
+public class ComplexTypeWithSystemObject
+{
+	public object SystemObject { get; set; }
+}
diff --git a/src/SoapCore.Tests/Wsdl/Services/IComplexTypeWithSystemObjectService.cs b/src/SoapCore.Tests/Wsdl/Services/IComplexTypeWithSystemObjectService.cs
new file mode 100644
index 00000000..b549e43b
--- /dev/null
+++ b/src/SoapCore.Tests/Wsdl/Services/IComplexTypeWithSystemObjectService.cs
@@ -0,0 +1,17 @@
+using System;
+using System.ServiceModel;
+
+namespace SoapCore.Tests.Wsdl.Services
+{
+	[ServiceContract]
+	public interface IComplexTypeWithSystemObjectService
+	{
+		[OperationContract]
+		ComplexTypeWithSystemObject Test();
+	}
+
+	public class ComplexTypeWithSystemObjectService : IComplexTypeWithSystemObjectService
+	{
+		public ComplexTypeWithSystemObject Test() => throw new NotImplementedException();
+	}
+}
diff --git a/src/SoapCore.Tests/Wsdl/WsdlTests.cs b/src/SoapCore.Tests/Wsdl/WsdlTests.cs
index b852f72d..dcf7ea3b 100644
--- a/src/SoapCore.Tests/Wsdl/WsdlTests.cs
+++ b/src/SoapCore.Tests/Wsdl/WsdlTests.cs
@@ -1407,6 +1407,25 @@ public async Task CheckComplexGenericTypeWithMultipleArgumentsWsdl(SoapSerialize
 			Assert.AreEqual($"tns:{genericTypeName}Of{genericTypeArgumentName}{genericTypeArgumentName}", typeName);
 		}
 
+		[DataTestMethod]
+		[DataRow(SoapSerializer.XmlSerializer)]
+		public async Task CheckComplexTypeWithSystemObjectWsdl(SoapSerializer soapSerializer)
+		{
+			var wsdl = await GetWsdlFromMetaBodyWriter<ComplexTypeWithSystemObjectService>(soapSerializer);
+			Trace.TraceInformation(wsdl);
+			Assert.IsNotNull(wsdl);
+
+			var root = XElement.Parse(wsdl);
+
+			var systemObjectElement = GetElements(root, _xmlSchema + "element")
+				.SingleOrDefault(a => a.Attribute("name")?.Value.Equals(nameof(ComplexTypeWithSystemObject.SystemObject)) == true);
+
+			Assert.IsNotNull(systemObjectElement);
+
+			var typeAttribute = systemObjectElement.Attribute("type");
+			Assert.IsNull(typeAttribute);
+		}
+
 		[TestMethod]
 		public void CheckSchemeOverride()
 		{
diff --git a/src/SoapCore/Meta/MetaBodyWriter.cs b/src/SoapCore/Meta/MetaBodyWriter.cs
index 74d8322e..caa980b1 100644
--- a/src/SoapCore/Meta/MetaBodyWriter.cs
+++ b/src/SoapCore/Meta/MetaBodyWriter.cs
@@ -1273,6 +1273,11 @@ private void AddSchemaType(XmlDictionaryWriter writer, TypeToBuild toBuild, stri
 						_complexTypeToBuild.Enqueue(newTypeToBuild);
 					}
 				}
+				else if (type == typeof(object))
+				{
+					writer.WriteAttributeString("name", name);
+					WriteQualification(writer, isUnqualified);
+				}
 				else if (toBuild.IsAnonumous)
 				{
 					if (string.IsNullOrEmpty(name))