fix(site-runtime): resolve SiteRuntime-017..019 — isolated attribute snapshot for child actors, corrected dispatcher doc, remove dead lifecycle handlers

src/ScadaLink.SiteRuntime/Actors/InstanceActor.cs

@@ -4,7 +4,6 @@ using Microsoft.Extensions.Logging;
 using ScadaLink.Commons.Messages.DataConnection;
 using ScadaLink.Commons.Messages.DebugView;
 using ScadaLink.Commons.Messages.Instance;
-using ScadaLink.Commons.Messages.Lifecycle;
 using ScadaLink.Commons.Messages.ScriptExecution;
 using ScadaLink.Commons.Messages.Streaming;
 using ScadaLink.Commons.Types.Enums;
@@ -102,20 +101,13 @@ public class InstanceActor : ReceiveActor
         // Handle static attribute writes
         Receive<SetStaticAttributeCommand>(HandleSetStaticAttribute);
 
-        // Handle lifecycle messages
-        Receive<DisableInstanceCommand>(_ =>
-        {
-            _logger.LogInformation("Instance {Instance} received disable command", _instanceUniqueName);
-            Sender.Tell(new InstanceLifecycleResponse(
-                _.CommandId, _instanceUniqueName, true, null, DateTimeOffset.UtcNow));
-        });
-
-        Receive<EnableInstanceCommand>(_ =>
-        {
-            _logger.LogInformation("Instance {Instance} received enable command", _instanceUniqueName);
-            Sender.Tell(new InstanceLifecycleResponse(
-                _.CommandId, _instanceUniqueName, true, null, DateTimeOffset.UtcNow));
-        });
+        // SiteRuntime-019: the disable/enable lifecycle is owned entirely by the
+        // Deployment Manager — DeploymentManagerActor.HandleDisable/HandleEnable
+        // stop or re-create the Instance Actor directly and reply to the caller.
+        // DisableInstanceCommand / EnableInstanceCommand are never routed to the
+        // Instance Actor, so no handlers are registered here. (The previous no-op
+        // handlers were dead code that implied a non-existent instance-side
+        // acknowledgement contract.)
 
         // WP-15: Handle script call requests — route to appropriate Script Actor (Ask pattern)
         Receive<ScriptCallRequest>(HandleScriptCallRequest);
@@ -590,11 +582,25 @@ public class InstanceActor : ReceiveActor
     /// WP-15: Script Actors spawned per script definition.
     /// WP-16: Alarm Actors spawned per alarm definition, as peers to Script Actors.
     /// WP-32: Compilation errors reject entire instance deployment (logged but actor still starts).
+    ///
+    /// SiteRuntime-017: each child is seeded from a private point-in-time snapshot
+    /// of <c>_attributes</c>, NOT the live dictionary. The snapshot is taken here on
+    /// the Instance Actor thread, so it is race-free; handing the live mutable
+    /// <see cref="System.Collections.Generic.Dictionary{TKey,TValue}"/> by reference
+    /// would let a child constructor enumerate it on the child's mailbox thread while
+    /// this actor mutates it in <c>HandleAttributeValueChanged</c>.
     /// </summary>
     private void CreateChildActors()
     {
         if (_configuration == null) return;
 
+        // SiteRuntime-017: snapshot the live attribute dictionary once, on the
+        // Instance Actor thread, before any child is constructed. Each child
+        // Props closure captures this immutable copy instead of the mutable
+        // _attributes field, so no child constructor ever enumerates a
+        // dictionary this actor is concurrently mutating.
+        var attributeSnapshot = new Dictionary<string, object?>(_attributes);
+
         // Create Script Actors
         foreach (var script in _configuration.Scripts)
         {
@@ -622,7 +628,7 @@ public class InstanceActor : ReceiveActor
                 _options,
                 _logger,
                 triggerExpression,
-                _attributes,
+                attributeSnapshot,
                 _healthCollector,
                 _serviceProvider));
 
@@ -672,7 +678,7 @@ public class InstanceActor : ReceiveActor
                 _options,
                 _logger,
                 triggerExpression,
-                _attributes,
+                attributeSnapshot,
                 _healthCollector));
 
             var actorRef = Context.ActorOf(props, $"alarm-{alarm.CanonicalName}");