fix(mgmt): MV-10 review fixes (ElementDataType fixed-field in LockEnforcer; graceful bad-DataType error; message consistency)

src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs

@@ -1442,7 +1442,7 @@ public class ManagementActor : ReceiveActor
     private static async Task<object?> HandleAddAttribute(IServiceProvider sp, AddTemplateAttributeCommand cmd, string user)
     {
         var svc = sp.GetRequiredService<TemplateService>();
-        var dataType = Enum.Parse<Commons.Types.Enums.DataType>(cmd.DataType, ignoreCase: true);
+        var dataType = ParseDataType(cmd.DataType);
         var elementType = ParseElementDataType(cmd.ElementDataType);
         ValidateAttributeTypes(cmd.Name, dataType, elementType, cmd.Value);
         var attr = new TemplateAttribute(cmd.Name)
@@ -1461,7 +1461,7 @@ public class ManagementActor : ReceiveActor
     private static async Task<object?> HandleUpdateAttribute(IServiceProvider sp, UpdateTemplateAttributeCommand cmd, string user)
     {
         var svc = sp.GetRequiredService<TemplateService>();
-        var dataType = Enum.Parse<Commons.Types.Enums.DataType>(cmd.DataType, ignoreCase: true);
+        var dataType = ParseDataType(cmd.DataType);
         var elementType = ParseElementDataType(cmd.ElementDataType);
         ValidateAttributeTypes(cmd.Name, dataType, elementType, cmd.Value);
         var attr = new TemplateAttribute(cmd.Name)
@@ -1477,6 +1477,19 @@ public class ManagementActor : ReceiveActor
         return result.IsSuccess ? result.Value : throw new ManagementCommandException(result.Error);
     }
 
+    /// <summary>
+    /// Parses a required data type token. Throws <see cref="ManagementCommandException"/>
+    /// (surfaced to the caller as a curated COMMAND_FAILED message) on an
+    /// unrecognised type name, rather than letting <c>Enum.Parse</c>'s
+    /// <see cref="ArgumentException"/> be masked as a generic internal error.
+    /// </summary>
+    private static Commons.Types.Enums.DataType ParseDataType(string? dataType)
+    {
+        if (!Enum.TryParse<Commons.Types.Enums.DataType>(dataType, ignoreCase: true, out var parsed))
+            throw new ManagementCommandException($"Unrecognised data type '{dataType}'.");
+        return parsed;
+    }
+
     /// <summary>
     /// Parses an optional element data type token. Returns null when the token is
     /// empty/whitespace; throws <see cref="ManagementCommandException"/> on an
@@ -1524,7 +1537,7 @@ public class ManagementActor : ReceiveActor
         }
         else if (elementType is not null)
         {
-            throw new ManagementCommandException("Element type is only valid on List attributes.");
+            throw new ManagementCommandException($"Attribute '{name}': ElementDataType is only valid on List attributes.");
         }
     }
 

src/ZB.MOM.WW.ScadaBridge.TemplateEngine/LockEnforcer.cs

@@ -15,7 +15,7 @@ namespace ZB.MOM.WW.ScadaBridge.TemplateEngine;
 ///   overrides that were previously blocked (TemplateEngine-022).
 ///
 /// Override granularity:
-/// - Attributes: Value and Description overridable; DataType and DataSourceReference fixed.
+/// - Attributes: Value and Description overridable; DataType, ElementDataType and DataSourceReference fixed.
 /// - Alarms: Priority, TriggerConfiguration, Description, OnTriggerScript overridable; Name and TriggerType fixed.
 /// - Scripts: Code, TriggerConfiguration, MinTimeBetweenRuns, ExecutionTimeoutSeconds, params/return overridable; Name fixed.
 /// - Lock flag applies to the entire member (attribute/alarm/script).
@@ -43,6 +43,12 @@ public static class LockEnforcer
             return $"Attribute '{original.Name}': DataType cannot be overridden (fixed).";
         }
 
+        // ElementDataType is fixed (the element scalar type of a List attribute) — cannot change
+        if (proposed.ElementDataType != original.ElementDataType)
+        {
+            return $"Attribute '{original.Name}': ElementDataType cannot be overridden (fixed).";
+        }
+
         // DataSourceReference is fixed — cannot change
         if (proposed.DataSourceReference != original.DataSourceReference)
         {

src/ZB.MOM.WW.ScadaBridge.TemplateEngine/TemplateService.cs

@@ -982,6 +982,7 @@ public class TemplateService
             {
                 Value = attr.Value,
                 DataType = attr.DataType,
+                ElementDataType = attr.ElementDataType,
                 IsLocked = attr.IsLocked,
                 Description = attr.Description,
                 DataSourceReference = attr.DataSourceReference,