There are a large number of error generating checks in the verify() function within config scripts that checks whether an interface exists. There is however, very few checks in the reverse when deleting the dependent interface.

Example:
There are checks when configuring an interface in OSPF:

vyos@vyos# set protocols ospf interface dum5 area 0
vyos@vyos# commit
Interface "dum5" does not exist!

[[protocols ospf]] failed
Commit failed

But if we delete the interface after OSPF has been configured, it won't fail:

vyos@vyos# set interfaces dummy dum5
vyos@vyos# set protocols ospf interface dum5 area 0
vyos@vyos# commit

vyos@vyos# delete interfaces dummy dum5
vyos@vyos# commit

This will lead to the entire OSPF section failing to load upon a reboot, potentially causing an outage for a customer.

It would be useful to have a single source of truth to whether an interface is configured as a dependent interface as a simple check.