T5467: removing ospf(v3) or isis interface in VRF context did not clear FRR config

To reproduce:

set vrf name red table 2000
set vrf name red protocols ospf interface eth1 area 0
set vrf name red protocols ospf parameters router-id 1.1.1.1
set interfaces ethernet eth1 vrf red
commit

FRR now has an interface config

vyos@vyos# vtysh -c "show run" no-header | sed -n "/^interface eth1/,/!/p"
interface eth1
 ip ospf area 0
 ip ospf dead-interval 40
exit

Now delete the interface from the OSPF(v3) or ISIS process

delete vrf name red protocols ospf interface
commit

It's still there

vyos@vyos# vtysh -c "show run" no-header | sed -n "/^interface eth1/,/!/p"
interface eth1
 ip ospf area 0
 ip ospf dead-interval 40
exit
!

Issue was caused in the FRR vtysh representation of an interface. It used to
have a "vrf <name>" marker in earlier versions but FRR 8.5 and later no longer
have the marker. So "interface eth1 vrf red" became "interface eth1" in vtysh,
but our regex expected the "vrf" identifier when modifying FRR config.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/conf_mode/protocols_ospfv3.py b/src/conf_mode/protocols_ospfv3.py
index e68fa1fe6..5b1adce30 100755
--- a/src/conf_mode/protocols_ospfv3.py
+++ b/src/conf_mode/protocols_ospfv3.py
@@ -64,7 +64,8 @@ def get_config(config=None):
     if interfaces_removed:
         ospfv3['interface_removed'] = list(interfaces_removed)
 
-    # Bail out early if configuration tree does not exist
+    # Bail out early if configuration tree does no longer exist. this must
+    # be done after retrieving the list of interfaces to be removed.
     if not conf.exists(base):
         ospfv3.update({'deleted' : ''})
         return ospfv3
@@ -166,7 +167,7 @@ def apply(ospfv3):
         if key not in ospfv3:
             continue
         for interface in ospfv3[key]:
-            frr_cfg.modify_section(f'^interface {interface}{vrf}', stop_pattern='^exit', remove_stop_mark=True)
+            frr_cfg.modify_section(f'^interface {interface}', stop_pattern='^exit', remove_stop_mark=True)
 
     if 'new_frr_config' in ospfv3:
         frr_cfg.add_before(frr.default_add_before, ospfv3['new_frr_config'])