Synchronise 2025.1 with upstream

neutron/db/l3_hamode_db.py

@@ -615,7 +615,8 @@ def _get_bindings_and_update_router_state_for_dead_agents(self, context,
             # List agents where router is active and agent is dead
             # and agents where router is standby and agent is dead
             for binding in bindings:
-                if not (binding.agent.is_active and
+                if not (binding.agent and
+                        binding.agent.is_active and
                         binding.agent.admin_state_up):
                     if binding.state == constants.HA_ROUTER_STATE_ACTIVE:
                         router_active_agents_dead.append(binding.agent)

neutron/tests/unit/db/test_l3_hamode_db.py

@@ -188,6 +188,29 @@ def test_get_l3_bindings_hosting_router_with_ha_states_ha_router(self):
         self.assertIn((self.agent1['id'], 'active'), agent_ids)
         self.assertIn((self.agent2['id'], 'standby'), agent_ids)
 
+    def test_get_l3_bindings_hosting_router_with_ha_states_null_agent(self):
+        router = self._create_router()
+        self.plugin.update_routers_states(
+            self.admin_ctx, {router['id']: 'active'}, self.agent1['host'])
+        mock_bindings = self.plugin.get_ha_router_port_bindings(
+            self.admin_ctx, [router['id']])
+        mock_bindings[0].state = constants.HA_ROUTER_STATE_STANDBY
+        target = (
+            'neutron.db.l3_hamode_db.L3_HA_NAT_db_mixin'
+            '.get_ha_router_port_bindings'
+        )
+        with (
+            mock.patch(
+                target,
+                return_value=mock_bindings),
+            mock.patch.object(mock_bindings[0], 'agent', new=None)
+        ):
+            bindings = (
+                self.plugin.get_l3_bindings_hosting_router_with_ha_states(
+                    self.admin_ctx, router['id'])
+            )
+        self.assertEqual(len(bindings), 1)
+
     def test_get_l3_bindings_hosting_router_with_ha_states_not_scheduled(self):
         router = self._create_router(ha=False)
         # Check that there no L3 agents scheduled for this router