fix(vtags): respawn equipment virtualtag child on in-place plan change (H1b, stillpending §1)

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/VirtualTags/VirtualTagHostActor.cs

@@ -39,6 +39,9 @@ public sealed class VirtualTagHostActor : ReceiveActor
     private readonly Dictionary<string, IActorRef> _children = new(StringComparer.Ordinal);
     // vtagId -> folder-scoped OPC UA NodeId the materialiser placed the variable at.
     private readonly Dictionary<string, string> _nodeIdByVtag = new(StringComparer.Ordinal);
+    // vtagId -> the plan its currently-spawned child was built from, so we can detect an in-place
+    // change (edited Expression/DependencyRefs) and stop+respawn the child to adopt it.
+    private readonly Dictionary<string, EquipmentVirtualTagPlan> _planByVtag = new(StringComparer.Ordinal);
 
     /// <summary>Factory method to create Props for a VirtualTagHostActor.</summary>
     /// <param name="publishActor">The OPC UA publish actor that consumes
@@ -78,6 +81,22 @@ public sealed class VirtualTagHostActor : ReceiveActor
             _children.Remove(vtagId);
         }
 
+        // Stop + forget children whose plan changed in place (edited Expression/DependencyRefs, or a
+        // toggled flag). EquipmentVirtualTagPlan has element-wise value equality, so an identical
+        // redeploy diffs equal and is left untouched. Forgetting the child here lets the spawn-new
+        // loop below recreate it from the new plan — children are auto-named (no explicit name), so a
+        // stop+respawn cannot hit the "actor name not unique" collision.
+        foreach (var p in msg.Plans)
+        {
+            if (_children.ContainsKey(p.VirtualTagId)
+                && _planByVtag.TryGetValue(p.VirtualTagId, out var prev)
+                && !prev.Equals(p))
+            {
+                Context.Stop(_children[p.VirtualTagId]); // PostStop unregisters the old mux interest.
+                _children.Remove(p.VirtualTagId);
+            }
+        }
+
         // Rebuild the NodeId map every apply so renames (Name/FolderPath/EquipmentId changes) are
         // picked up. The map only contains currently-desired vtags, so a result for a removed vtag
         // finds no entry and is dropped.
@@ -87,15 +106,13 @@ public sealed class VirtualTagHostActor : ReceiveActor
             _nodeIdByVtag[p.VirtualTagId] = NodeIdFor(p);
         }
 
-        // Spawn children for new vtagIds only — existing children keep their mux subscriptions and
-        // last-value dedup state. Expression/dependency changes on an existing vtag are NOT
-        // re-applied here; the loader's vtags are stable, and a future enhancement can stop+respawn
-        // a child whose plan changed (the diff already identifies ChangedEquipmentVirtualTags).
+        // Spawn children for vtagIds that have no live child. This covers genuinely-new vtags AND any
+        // vtag whose child was just forgotten above because its plan changed in place — that child is
+        // recreated here from the new plan, adopting the edited Expression/DependencyRefs. Children
+        // whose plan was unchanged still have a live entry and are skipped, keeping their mux
+        // subscriptions and last-value dedup state.
         foreach (var p in msg.Plans)
         {
-            // TODO(equipment-virtualtags): when a plan's Expression/DependencyRefs change in place
-            // (ChangedEquipmentVirtualTags), stop+respawn the child here; today only spawn-new/stop-removed
-            // is handled (loader vtags are stable).
             if (_children.ContainsKey(p.VirtualTagId)) continue;
 
             // Auto-name the child: vtagIds can contain characters illegal in actor names, so let Akka
@@ -113,6 +130,14 @@ public sealed class VirtualTagHostActor : ReceiveActor
             _log.Debug("VirtualTagHost: spawned child for vtag {VirtualTagId}", p.VirtualTagId);
         }
 
+        // Refresh the plan map to exactly the desired set so the next apply can detect in-place
+        // changes against what each live child was actually built from.
+        _planByVtag.Clear();
+        foreach (var p in msg.Plans)
+        {
+            _planByVtag[p.VirtualTagId] = p;
+        }
+
         _log.Debug("VirtualTagHost: applied (desired={Desired}, children={Children})",
             desired.Count, _children.Count);
     }