feat(config): make Equipment.DriverInstanceId nullable + driver-less AdminUI support + migration

docs/plans/2026-06-08-driverless-equipment-namespace-design.md

@@ -106,6 +106,15 @@ In `cmd_populate_equipment`:
   become no-ops; remove for clarity. Keep the `Namespace` INSERT/teardown.
 - Fix the stale `# … "an Equipment namespace has a driver" expectations` comment.
 
+### AdminUI — two production derefs (found at build time, not by the grep sweep)
+Making the column nullable surfaced two `.razor` sites the impact grep missed (caught by `TreatWarningsAsErrors`):
+- `Components/Pages/Clusters/TagEdit.razor:191` — `db.Equipment.Where(e => driverIds.Contains(e.DriverInstanceId))` (CS8604).
+  Behavior-preserving fix: guard `e.DriverInstanceId != null && …` (SQL already excludes NULL from an `IN` set, so this only satisfies the compiler).
+- `Components/Pages/Clusters/EquipmentEdit.razor` — the equipment editor loads `DriverInstanceId` into a non-null
+  `FormModel` (line 183, CS8601) and **mandates** a driver on save (`"Pick a driver instance."`). Decision: give it
+  **full driver-less support** — `FormModel.DriverInstanceId` → `string?`, add a "(none / driver-less)" option to the
+  driver dropdown, relax the mandatory-driver validation, and persist NULL when none is selected (normalize empty → null).
+
 ### Noted, not changing (YAGNI)
 - `sp_ComputeGenerationDiff` includes `DriverInstanceId` in a `CHECKSUM(...)`. It is NULL-tolerant for
   this one-time transition and sits on the **dormant** generation-diff path (the active deploy gate is

docs/plans/2026-06-08-driverless-equipment-namespace.md

@@ -20,9 +20,15 @@
 
 **Files:**
 - Modify: `src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Entities/Equipment.cs` (line ~23)
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Clusters/TagEdit.razor` (~line 191 — null-guard the EF predicate)
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Clusters/EquipmentEdit.razor` (FormModel + dropdown + save — full driver-less support)
 - Create: `src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/<timestamp>_NullableEquipmentDriverInstanceId.cs` (generated by `dotnet ef`)
 - Auto-modify: `src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/OtOpcUaConfigDbContextModelSnapshot.cs` (regenerated by `dotnet ef`)
 
+**AdminUI surface (found at build time — the nullable change breaks two `.razor` sites under `TreatWarningsAsErrors`):**
+- `TagEdit.razor:191`: `db.Equipment.Where(e => driverIds.Contains(e.DriverInstanceId))` → guard `e.DriverInstanceId != null && driverIds.Contains(e.DriverInstanceId)` (behavior-preserving; SQL already excludes NULL).
+- `EquipmentEdit.razor`: full driver-less support — `FormModel.DriverInstanceId` → `string?`; add a "(none / driver-less)" option to the driver `<select>`; remove the mandatory `if (string.IsNullOrEmpty(_form.DriverInstanceId)) { _error = "Pick a driver instance."; return; }` check (~line 209); on save (both the IsNew `Add` ~line 222 and the update ~line 245) write `string.IsNullOrWhiteSpace(_form.DriverInstanceId) ? null : _form.DriverInstanceId`.
+
 **Context:** `DriverInstanceId` is currently `public required string DriverInstanceId { get; set; }`. The EF config `OtOpcUaConfigDbContext.ConfigureEquipment` has **no `.IsRequired()`** call and **no FK relationship** for it (it's a logical FK only) — so EF infers NOT NULL purely from the C# `required string` type. Changing the type to `string?` flips the column to nullable; no fluent-config change is needed. The index `IX_Equipment_Driver` is a plain non-unique index and stays valid on a nullable column.
 
 **Step 1 — Change the entity property.** In `Equipment.cs`, change:

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Entities/Equipment.cs

@@ -19,8 +19,11 @@ public sealed class Equipment
     /// <summary>UUIDv4, IMMUTABLE across all generations of the same EquipmentId. Downstream-consumer join key.</summary>
     public Guid EquipmentUuid { get; set; }
 
-    /// <summary>Logical FK to the driver providing data for this equipment.</summary>
-    public required string DriverInstanceId { get; set; }
+    /// <summary>
+    ///     Optional logical FK to the driver providing data for this equipment.
+    ///     <c>null</c> = VirtualTag-only / driver-less equipment (no field driver).
+    /// </summary>
+    public string? DriverInstanceId { get; set; }
 
     /// <summary>Optional logical FK to a multi-device driver's device.</summary>
     public string? DeviceId { get; set; }

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/20260608104706_NullableEquipmentDriverInstanceId.cs

@@ -0,0 +1,40 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
+{
+    /// <inheritdoc />
+    public partial class NullableEquipmentDriverInstanceId : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<string>(
+                name: "DriverInstanceId",
+                table: "Equipment",
+                type: "nvarchar(64)",
+                maxLength: 64,
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "nvarchar(64)",
+                oldMaxLength: 64);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<string>(
+                name: "DriverInstanceId",
+                table: "Equipment",
+                type: "nvarchar(64)",
+                maxLength: 64,
+                nullable: false,
+                defaultValue: "",
+                oldClrType: typeof(string),
+                oldType: "nvarchar(64)",
+                oldMaxLength: 64,
+                oldNullable: true);
+        }
+    }
+}

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/OtOpcUaConfigDbContextModelSnapshot.cs

@@ -546,7 +546,6 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
                         .HasColumnType("nvarchar(512)");
 
                     b.Property<string>("DriverInstanceId")
-                        .IsRequired()
                         .HasMaxLength(64)
                         .HasColumnType("nvarchar(64)");
 

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Clusters/EquipmentEdit.razor

@@ -72,7 +72,7 @@ else
                     <div class="col-md-6 mb-3">
                         <label class="form-label" for="driver">Driver instance</label>
                         <InputSelect id="driver" @bind-Value="_form.DriverInstanceId" class="form-select form-select-sm">
-                            <option value="">— pick a driver —</option>
+                            <option value="">(none / driver-less)</option>
                             @foreach (var d in _drivers)
                             {
                                 <option value="@d.DriverInstanceId">@d.DriverInstanceId &mdash; @d.Name (@d.DriverType)</option>
@@ -206,7 +206,6 @@ else
         try
         {
             if (string.IsNullOrEmpty(_form.UnsLineId)) { _error = "Pick a UNS line."; return; }
-            if (string.IsNullOrEmpty(_form.DriverInstanceId)) { _error = "Pick a driver instance."; return; }
 
             await using var db = await DbFactory.CreateDbContextAsync();
             if (IsNew)
@@ -219,7 +218,7 @@ else
                 {
                     EquipmentId = equipmentId,
                     EquipmentUuid = uuid,
-                    DriverInstanceId = _form.DriverInstanceId,
+                    DriverInstanceId = string.IsNullOrWhiteSpace(_form.DriverInstanceId) ? null : _form.DriverInstanceId,
                     UnsLineId = _form.UnsLineId,
                     Name = _form.Name,
                     MachineCode = _form.MachineCode,
@@ -242,7 +241,7 @@ else
                 var entity = await db.Equipment.FirstOrDefaultAsync(e => e.EquipmentId == EquipmentId);
                 if (entity is null) { _error = "Row no longer exists."; return; }
                 db.Entry(entity).Property(e => e.RowVersion).OriginalValue = _form.RowVersion;
-                entity.DriverInstanceId = _form.DriverInstanceId;
+                entity.DriverInstanceId = string.IsNullOrWhiteSpace(_form.DriverInstanceId) ? null : _form.DriverInstanceId;
                 entity.UnsLineId = _form.UnsLineId;
                 entity.Name = _form.Name;
                 entity.MachineCode = _form.MachineCode;
@@ -292,7 +291,7 @@ else
         public string Name { get; set; } = "";
         [Required] public string MachineCode { get; set; } = "";
         [Required] public string UnsLineId { get; set; } = "";
-        [Required] public string DriverInstanceId { get; set; } = "";
+        public string? DriverInstanceId { get; set; }
         public string? ZTag { get; set; }
         public string? SAPID { get; set; }
         public string? Manufacturer { get; set; }

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Clusters/TagEdit.razor

@@ -188,7 +188,7 @@ else
             d => nsById.TryGetValue(d.NamespaceId, out var ns) ? ns : namespaces.First());
         var driverIds = _drivers.Select(d => d.DriverInstanceId).ToHashSet();
         _equipment = await db.Equipment.AsNoTracking()
-            .Where(e => driverIds.Contains(e.DriverInstanceId))
+            .Where(e => e.DriverInstanceId != null && driverIds.Contains(e.DriverInstanceId))
             .OrderBy(e => e.MachineCode)
             .ToListAsync();