heat stack-update failed when removing a VLAN

[Sowmya Divvi]

I have tried to remove a VLAN in yaml template by updating stack, but it's failed with the error message
"Resource update failed:BadRequest : resources.subport:invalid input for operation vlan id is used already on trunkport."

success scenario:
I have launched stack with specifying following vlans:

vlan_ids: ['116', '118', '119']

and updated stack with vlan_ids: ['116', '118']

stack create and update are successful.

Fail scenario:

I have launched stack with specifying following vlans:

vlan_ids: ['116', '118', '119']

and updated stack with vlan_ids: ['116', '119']

stack update is failed.

While updating stack, it's unable to delete the middle vlan.

(i.e)In above case i am unable to delete vlan '118' but with the last vlan(119) in the right, we didn't have any problems while updating the stack.

[Thomas Herve (therve)]

Please attach the templates used, thanks

[Sowmya Divvi (sowmya)]

I have used hot.yaml as main template and vsg_env.yaml as environment file and vsg_pmp as nested template to launch stack and vsg_update.yaml to update the stack