Merge "Make prevent_l3_port_deletion handle missing port" into stable/juno

neutron/db/l3_db.py

@@ -881,7 +881,11 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase):
         to /ports, but rather via other API calls that perform the proper
         deletion checks.
         """
-        port_db = self._core_plugin._get_port(context, port_id)
+        try:
+            port_db = self._core_plugin._get_port(context, port_id)
+        except n_exc.PortNotFound:
+            # non-existent ports don't need to be protected from deletion
+            return
         if port_db['device_owner'] in self.router_device_owners:
             # Raise port in use only if the port has IP addresses
             # Otherwise it's a stale port that can be removed

neutron/plugins/ml2/plugin.py

@@ -985,8 +985,6 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                                session.begin(subtransactions=True)):
             port_db, binding = db.get_locked_port_and_binding(session, id)
             if not port_db:
-                # the port existed when l3plugin.prevent_l3_port_deletion
-                # was called but now is already gone
                 LOG.debug(_("The port '%s' was deleted"), id)
                 return
             port = self._make_port_dict(port_db)

neutron/tests/unit/test_l3_plugin.py

@@ -2154,7 +2154,12 @@ class L3NatDBIntTestCase(L3BaseForIntTests, L3NatTestCaseBase):
 class L3NatDBSepTestCase(L3BaseForSepTests, L3NatTestCaseBase):
 
     """Unit tests for a separate L3 routing service plugin."""
-    pass
+    def test_port_deletion_prevention_handles_missing_port(self):
+        pl = manager.NeutronManager.get_service_plugins().get(
+            service_constants.L3_ROUTER_NAT)
+        self.assertIsNone(
+            pl.prevent_l3_port_deletion(context.get_admin_context(), 'fakeid')
+        )
 
 
 class L3NatDBIntTestCaseXML(L3NatDBIntTestCase):