From 0e00a08ca1949c799ba14ab0369fb64451d601f3 Mon Sep 17 00:00:00 2001
From: Marcel Vielhaus <mvielhaus@phoenixcontact.com>
Date: Tue, 10 Dec 2024 17:37:49 +0100
Subject: [PATCH] Filter generic base types when seaching for the resource
 proxy type

When inheriting from a generic base type without adding additional interfaces, a resource can still have a generated proxy. However, in that case the proxy builder would assume the generic base type to be the best possible fit, which cannot be proxified.
---
 .../Resources/ResourceTypeController.cs            |  8 +++++---
 .../Mocks/ResourceWithGenericMethod.cs             |  6 ++++++
 .../TypeControllerTests.cs                         | 14 ++++++++++++++
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/Moryx.Resources.Management/Resources/ResourceTypeController.cs b/src/Moryx.Resources.Management/Resources/ResourceTypeController.cs
index 893ef29a1..5140fb217 100644
--- a/src/Moryx.Resources.Management/Resources/ResourceTypeController.cs
+++ b/src/Moryx.Resources.Management/Resources/ResourceTypeController.cs
@@ -264,17 +264,19 @@ private ResourceProxy InstantiateProxy(string typeName, Resource instance)
         /// </summary>
         private void ProvideProxyType(Type resourceType)
         {
-            // Step 1: Find the least specific base type that offers the same amount of interfaces
+            // Step 1: Find the least specific base type that offers the same amount of interfaces and is not a generic itself
             // ReSharper disable once AssignNullToNotNullAttribute -> FullName should be not null
             var targetType = _typeCache[resourceType.ResourceType()];
             var linker = targetType;
 
             var interfaces = RelevantInterfaces(linker);
-            // Move up the type tree until the parent offers less interfaces than the current linker
-            while (linker.BaseType != null && interfaces.Count == RelevantInterfaces(linker.BaseType).Count)
+            // Move up the type tree until the parent offers less interfaces than the current linker, is abstract or a generic
+            while (linker.BaseType != null && !linker.BaseType.ResourceType.IsGenericType 
+                && interfaces.Count == RelevantInterfaces(linker.BaseType).Count)
             {
                 linker = linker.BaseType;
             }
+                
 
             // Step 2: Check if we already created a proxy for this type. If we already
             // did use this one for the requested type as well.
diff --git a/src/Tests/Moryx.Resources.Management.Tests/Mocks/ResourceWithGenericMethod.cs b/src/Tests/Moryx.Resources.Management.Tests/Mocks/ResourceWithGenericMethod.cs
index ee751b561..d8574ca9b 100644
--- a/src/Tests/Moryx.Resources.Management.Tests/Mocks/ResourceWithGenericMethod.cs
+++ b/src/Tests/Moryx.Resources.Management.Tests/Mocks/ResourceWithGenericMethod.cs
@@ -57,4 +57,10 @@ public void RaiseEvent()
             throw new NotImplementedException();
         }
     }
+
+    public interface IGenericBaseResourceInterface : IResource { }
+
+    public class GenericBaseResource<T> : Resource, IGenericBaseResourceInterface { }
+
+    public class InheritingFromGenericResource : GenericBaseResource<object> { }
 }
diff --git a/src/Tests/Moryx.Resources.Management.Tests/TypeControllerTests.cs b/src/Tests/Moryx.Resources.Management.Tests/TypeControllerTests.cs
index 8ef3f51f7..ccb8a8f9c 100644
--- a/src/Tests/Moryx.Resources.Management.Tests/TypeControllerTests.cs
+++ b/src/Tests/Moryx.Resources.Management.Tests/TypeControllerTests.cs
@@ -222,6 +222,20 @@ public void ProxyBuilderFiltersGenericInterfaces()
             Assert.IsFalse(typeof(IGenericMethodCall).IsAssignableFrom(proxy.GetType()));
         }
 
+        [Test]
+        public void ProxyBuilderSkipsGenericBaseTypes()
+        {
+            // Arrange
+            var driver = new InheritingFromGenericResource { Id = 42, Name = "A non generic resource inheriting from a generic base type" };
+
+            // Act
+            var proxy = _typeController.GetProxy(driver);
+
+            // Assert
+            Assert.IsNotNull(proxy);
+            Assert.IsFalse(typeof(GenericBaseResource<object>).IsAssignableFrom(proxy.GetType()));
+        }
+
         [Test]
         public void FacadeExceptionForGenericProxy()
         {