Fix BaseEventState.MemberwiseClone() to pass Parent to Activator.CreateInstance (#3361)

* Fix BaseEventState.MemberwiseClone() to pass Parent to Activator.CreateInstance

Co-authored-by: romanett <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: romanett <[email protected]>

Author: Copilot

Stack/Opc.Ua.Core/Stack/State/BaseEventState.cs

@@ -83,7 +83,7 @@ public override object Clone()
         /// </returns>
         public new object MemberwiseClone()
         {
-            var clone = (BaseEventState)Activator.CreateInstance(GetType());
+            var clone = (BaseEventState)Activator.CreateInstance(GetType(), Parent);
             return CloneChildren(clone);
         }
     }

Tests/Opc.Ua.Core.Tests/Stack/State/NodeStateTests.cs

@@ -139,4 +139,59 @@ private static bool IsNodeStateType(Type systemType)
             return CreateDefaultNodeStateType(systemType) is NodeState;
         }
     }
+
+    /// <summary>
+    /// Tests for BaseEventState.MemberwiseClone.
+    /// </summary>
+    [TestFixture]
+    [Category("BaseEventState")]
+    [SetCulture("en-us")]
+    [SetUICulture("en-us")]
+    [Parallelizable]
+    public class BaseEventStateTests
+    {
+        /// <summary>
+        /// Verify that MemberwiseClone works correctly for BaseEventState.
+        /// </summary>
+        [Test]
+        public void MemberwiseCloneBaseEventStateSucceeds()
+        {
+            var parent = new BaseObjectState(null);
+            var eventState = new BaseEventState(parent);
+
+            var clone = (BaseEventState)eventState.MemberwiseClone();
+
+            Assert.That(clone, Is.Not.Null);
+            Assert.That(clone.Parent, Is.SameAs(parent));
+        }
+
+        /// <summary>
+        /// Verify that MemberwiseClone works correctly for BaseEventState with null parent.
+        /// </summary>
+        [Test]
+        public void MemberwiseCloneBaseEventStateWithNullParentSucceeds()
+        {
+            var eventState = new BaseEventState(null);
+
+            var clone = (BaseEventState)eventState.MemberwiseClone();
+
+            Assert.That(clone, Is.Not.Null);
+            Assert.That(clone.Parent, Is.Null);
+        }
+
+        /// <summary>
+        /// Verify that Clone works correctly for derived event types.
+        /// </summary>
+        [Test]
+        public void CloneNonExclusiveLimitAlarmStateSucceeds()
+        {
+            var parent = new BaseObjectState(null);
+            var alarmState = new NonExclusiveLimitAlarmState(parent);
+
+            var clone = (NonExclusiveLimitAlarmState)alarmState.Clone();
+
+            Assert.That(clone, Is.Not.Null);
+            Assert.That(clone.Parent, Is.SameAs(parent));
+        }
+    }
 }