fix

src/router.rs

 use crate::quality::Quality;
 use crate::settings::{HALF_LIFE, PENALTY, PENALTY_MIN};
 use crate::shared::{
-    data::{DATABASE, GatewayGroupID, GatewayID, RegionID, RouterID},
+    data::{self, DATABASE, GatewayGroupID, GatewayID, RegionID, RouterID},
     protocol::{Downlink, MessageType, PeerQuality, Uplink},
 };
 use crate::{UpdatingState, shared};
@@ -73,13 +73,6 @@ impl Router {
         self.addr.is_some()
     }
 
-    pub fn apply(&mut self, via: &mut BTreeMap<RouterID, RouterID>, plan: &mut BTreeMap<RegionID, BTreeMap<GatewayGroupID, GatewayID>>) {
-        self.via.append(via);
-        for (region, mut plan) in std::mem::take(plan) {
-            self.plan.entry(region).or_default().append(&mut plan);
-        }
-    }
-
     pub fn on_message(&mut self, uplink: &mut Uplink, addr: SocketAddr, updating: &mut UpdatingState, now: Instant) -> Option<Downlink> {
         if uplink.peers.len() == self.peers.len() {
             for (current, new) in self.peers.values_mut().zip(&mut uplink.peers) {
@@ -102,7 +95,7 @@ impl Router {
                     for (to, via) in self.via.iter_mut() {
                         *via = *to;
                     }
-                    self.apply(&mut uplink.via, &mut uplink.plan);
+                    data::GatewayGroup::apply(&mut self.via, &mut uplink.via, &mut self.plan, &mut uplink.plan);
                     self.online(addr, now);
                 }
                 None
@@ -112,7 +105,7 @@ impl Router {
                     self.online(addr, now);
                     if updating.router_id == self.id {
                         updating.router_id = Default::default();
-                        self.apply(&mut updating.message.via, &mut updating.message.plan);
+                        data::GatewayGroup::apply(&mut self.via, &mut updating.message.via, &mut self.plan, &mut updating.message.plan);
                         self.last_update = now;
                     }
                     None

src/shared/gateway_group.rs

@@ -47,6 +47,20 @@ impl GatewayGroup {
             .collect()
     }
 
+    pub fn apply(
+        self_via: &mut BTreeMap<RouterID, RouterID>,
+        new_via: &mut BTreeMap<RouterID, RouterID>,
+        self_plan: &mut BTreeMap<RegionID, BTreeMap<GatewayGroupID, GatewayID>>,
+        new_plan: &mut BTreeMap<RegionID, BTreeMap<GatewayGroupID, GatewayID>>,
+    ) {
+        self_via.append(new_via);
+        for (region, inner) in new_plan {
+            if let Some(p) = self_plan.get_mut(region) {
+                p.append(inner);
+            }
+        }
+    }
+
     fn guess(id: RouterID, gw: &data::Gateway, region: usize) -> i32 {
         gw.metrics[region].saturating_add(gw.cost_outbound).saturating_add(if gw.router == id { 0 } else { 100 })
     }