From b8ed3cc7828d7dbc232d2b1ad510d2de4d117bf1 Mon Sep 17 00:00:00 2001
From: Copilot <198982749+Copilot@users.noreply.github.com>
Date: Thu, 4 Dec 2025 15:34:51 +0100
Subject: [PATCH] Fix BaseEventState.MemberwiseClone() to pass Parent to
 Activator.CreateInstance (#3361)

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

Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
---
 .../Opc.Ua.Core/Stack/State/BaseEventState.cs |  2 +-
 .../Stack/State/NodeStateTests.cs             | 55 +++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/Stack/Opc.Ua.Core/Stack/State/BaseEventState.cs b/Stack/Opc.Ua.Core/Stack/State/BaseEventState.cs
index 9cbf864376..547797d749 100644
--- a/Stack/Opc.Ua.Core/Stack/State/BaseEventState.cs
+++ b/Stack/Opc.Ua.Core/Stack/State/BaseEventState.cs
@@ -83,7 +83,7 @@ namespace Opc.Ua
         /// </returns>
         public new object MemberwiseClone()
         {
-            var clone = (BaseEventState)Activator.CreateInstance(GetType());
+            var clone = (BaseEventState)Activator.CreateInstance(GetType(), Parent);
             return CloneChildren(clone);
         }
     }
diff --git a/Tests/Opc.Ua.Core.Tests/Stack/State/NodeStateTests.cs b/Tests/Opc.Ua.Core.Tests/Stack/State/NodeStateTests.cs
index e0e46b5dee..24b5722c40 100644
--- a/Tests/Opc.Ua.Core.Tests/Stack/State/NodeStateTests.cs
+++ b/Tests/Opc.Ua.Core.Tests/Stack/State/NodeStateTests.cs
@@ -139,4 +139,59 @@ namespace Opc.Ua.Core.Tests.Stack.State
             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));
+        }
+    }
 }