Sbmsi bug fix (#17249)

* Fixing identity update bug and making disable of user assigned identity possible

* Making fixes

Author: damodaravadhani

src/ServiceBus/ServiceBus/Utilities/ServiceBusClient.cs

@@ -114,7 +114,7 @@ public PSNamespaceAttributes BeginCreateNamespace(string resourceGroupName, stri
             if (identityType != null)
             {
                 parameter.Identity = new Identity();
-                parameter.Identity = FindIdentity(identityType);
+                parameter.Identity.Type = FindIdentity(identityType);
             }
 
             if (identityIds != null)
@@ -132,6 +132,11 @@ public PSNamespaceAttributes BeginCreateNamespace(string resourceGroupName, stri
                 {
                     parameter.Identity.UserAssignedIdentities = UserAssignedIdentities;
                 }
+
+                if (parameter.Identity.Type == ManagedServiceIdentityType.None || parameter.Identity.Type == ManagedServiceIdentityType.SystemAssigned)
+                {
+                    throw new Exception("Please change -IdentityType to 'UserAssigned' or 'SystemAssigned, UserAssigned' if you want to add User Assigned Identities");
+                }
             }
 
             if (encryptionconfigs != null)
@@ -204,9 +209,14 @@ public PSNamespaceAttributes UpdateNamespace(string resourceGroupName, string na
 
             if (identityType != null)
             {
-                parameter.Identity = new Identity();
-                parameter.Identity = FindIdentity(identityType);
-                if (parameter.Identity.Type == ManagedServiceIdentityType.None)
+                if (parameter.Identity == null)
+                {
+                    parameter.Identity = new Identity();
+                }
+
+                parameter.Identity.Type = FindIdentity(identityType);
+
+                if (parameter.Identity.Type == ManagedServiceIdentityType.None || parameter.Identity.Type == ManagedServiceIdentityType.SystemAssigned)
                 {
                     parameter.Identity.UserAssignedIdentities = null;
                 }
@@ -226,6 +236,10 @@ public PSNamespaceAttributes UpdateNamespace(string resourceGroupName, string na
                 {
                     parameter.Identity.UserAssignedIdentities = UserAssignedIdentities;
                 }
+                if (parameter.Identity.Type == ManagedServiceIdentityType.None || parameter.Identity.Type == ManagedServiceIdentityType.SystemAssigned)
+                {
+                    throw new Exception("Please change -IdentityType to 'UserAssigned' or 'SystemAssigned, UserAssigned' if you want to add User Assigned Identities");
+                }
             }
 
             if (encryptionconfigs != null)
@@ -264,26 +278,26 @@ public PSNamespaceAttributes UpdateNamespace(string resourceGroupName, string na
             return new PSNamespaceAttributes(response);
         }
 
-        public Identity FindIdentity(string identityType)
+        public ManagedServiceIdentityType FindIdentity(string identityType)
         {
-            Identity identity = new Identity();
-            
+            ManagedServiceIdentityType Type = ManagedServiceIdentityType.None;
             if (identityType == SystemAssigned)
-                identity.Type = ManagedServiceIdentityType.SystemAssigned;
+                Type = ManagedServiceIdentityType.SystemAssigned;
 
             else if (identityType == UserAssigned)
-                identity.Type = ManagedServiceIdentityType.UserAssigned;
+                Type = ManagedServiceIdentityType.UserAssigned;
 
             else if (identityType == SystemAssignedUserAssigned)
-                identity.Type = ManagedServiceIdentityType.SystemAssignedUserAssigned;
+                Type = ManagedServiceIdentityType.SystemAssignedUserAssigned;
 
             else if (identityType == None)
-                identity.Type = ManagedServiceIdentityType.None;
+                Type = ManagedServiceIdentityType.None;
 
-            return identity;
+            return Type;
         }
 
 
+
         public bool BeginDeleteNamespace(string resourceGroupName, string namespaceName)
         {
             Client.Namespaces.DeleteWithHttpMessagesAsync(resourceGroupName, namespaceName, null, new CancellationToken()).ConfigureAwait(false);