fix: attachable despawn vs detach order & ownership test. (#3895)

* fix

Fixing an issue where attachables could throw an exception if an item's attachable is attached to a node and is set to detach upon ownership change and not despawn, then if the attachable item is despawned while still attached it never detaches itself from the node during a shutdown.

Fixing an issue where sorting no longer is a guaranteed order.

* update

Adding changelog entry.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -23,6 +23,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Fixed issue where an attachable could log an error upon being de-spawned during shutdown. (#3895)
 - NestedNetworkVariables initialized with no value no longer throw an error. (#3891)
 
 ### Security

com.unity.netcode.gameobjects/Runtime/Components/Helpers/AttachableBehaviour.cs

@@ -278,7 +278,7 @@ internal void ForceDetach()
         /// <inheritdoc/>
         public override void OnNetworkPreDespawn()
         {
-            if (AutoDetach.HasFlag(AutoDetachTypes.OnDespawn))
+            if (NetworkManager.ShutdownInProgress || AutoDetach.HasFlag(AutoDetachTypes.OnDespawn))
             {
                 ForceDetach();
             }
@@ -474,10 +474,11 @@ internal void InternalDetach()
         /// </summary>
         public void Detach()
         {
-            if (!gameObject)
+            if (!gameObject || NetworkObject == null || NetworkManager == null || NetworkManager.ShutdownInProgress)
             {
                 return;
             }
+
             if (!IsSpawned)
             {
                 NetworkLog.LogError($"[{name}][Detach][Not Spawned] Cannot detach if not spawned!");

com.unity.netcode.gameobjects/Tests/Runtime/NetworkObject/NetworkObjectNetworkClientOwnedObjectsTests.cs

@@ -75,7 +75,7 @@ public IEnumerator WhenOwnershipIsChanged_OwnershipValuesUpdateCorrectly()
             Assert.IsFalse(serverBehaviour.IsOwnedByServer);
             Assert.AreEqual(m_ClientNetworkManagers[0].LocalClientId, serverBehaviour.OwnerClientId);
 
-            var clientObject = FindObjects.ByType<NetworkObject>(orderByIdentifier: true).Where((obj) => obj.NetworkManagerOwner == m_ClientNetworkManagers[0]).FirstOrDefault();
+            var clientObject = m_ClientNetworkManagers[0].SpawnManager.SpawnedObjects.ContainsKey(serverObject.NetworkObjectId) ? m_ClientNetworkManagers[0].SpawnManager.SpawnedObjects[serverObject.NetworkObjectId] : null;
 
             Assert.IsNotNull(clientObject);
             Assert.IsTrue(clientObject.IsOwner);