feature: dont disable a computer account if a duplicate, commissioned device exists

Disco.Services/Devices/Importing/Fields/DeviceDecommissionedDateImportField.cs

@@ -6,6 +6,7 @@ using Disco.Services.Logging;
 using System;
 using System.Collections.Generic;
 using System.Data;
+using System.Data.Entity;
 using System.Globalization;
 using System.Linq;
 
@@ -99,6 +100,14 @@ namespace Disco.Services.Devices.Importing.Fields
         public override void Applied(DiscoDataContext Database, Device Device, ref bool DeviceADDescriptionSet)
         {
             if (ActiveDirectory.IsValidDomainAccountId(Device.DeviceDomainId))
+            {
+                // Don't disable if another active device with the same name exists
+                var duplicateNamedDevice = Database.Devices
+                    .Where(i => i.DeviceDomainId == Device.DeviceDomainId &&
+                                i.SerialNumber != Device.SerialNumber &&
+                                i.DecommissionedDate == null)
+                    .Any();
+                if (!duplicateNamedDevice)
                 {
                     var adAccount = Device.ActiveDirectoryAccount();
 
@@ -131,6 +140,7 @@ namespace Disco.Services.Devices.Importing.Fields
                     }
                 }
             }
+        }
 
         public override int? GuessColumn(DiscoDataContext Database, IDeviceImportContext Context, IDeviceImportDataReader DataReader)
         {