routing: don't free a single nc on prune, only entire channel.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

gossipd/routing.c

@@ -1328,30 +1328,20 @@ void route_prune(struct routing_state *rstate)
 		if (!chan->public)
 			continue;
 
-		for (int i = 0; i < 2; i++) {
-			struct node_connection *nc = chan->connections[i];
-
-			if (!nc)
-				continue;
-
-			if (nc->last_timestamp > highwater) {
-				/* Still alive */
-				continue;
-			}
-
+		if (chan->connections[0]->last_timestamp < highwater
+		    && chan->connections[1]->last_timestamp < highwater) {
 			status_trace(
-			    "Pruning channel %s/%d from network view (age %"PRIu64"s)",
+			    "Pruning channel %s from network view (ages %"PRIu64" and %"PRIu64"s)",
 			    type_to_string(trc, struct short_channel_id,
 					   &chan->scid),
-			    nc->flags & 0x1,
-			    now - nc->last_timestamp);
+			    now - chan->connections[0]->last_timestamp,
+			    now - chan->connections[1]->last_timestamp);
 
-			/* This may free nodes, so do outside loop. */
-			tal_steal(pruned, nc);
+			/* This may perturb iteration so do outside loop. */
+			tal_steal(pruned, chan);
 		}
 	}
 
-	/* This frees all the node_connections: may free routing_channel and
-	 * even nodes. */
+	/* This frees all the routing_channels and maybe even nodes. */
 	tal_free(pruned);
 }

tests/test_lightningd.py

@@ -1898,15 +1898,8 @@ class LightningDTests(BaseLightningDTests):
         time.sleep(1)
         l3.stop()
 
-        l1.daemon.wait_for_logs([
-            "Pruning channel {}/{} from network view".format(scid2, 0),
-            "Pruning channel {}/{} from network view".format(scid2, 1),
-        ])
-
-        l2.daemon.wait_for_logs([
-            "Pruning channel {}/{} from network view".format(scid2, 0),
-            "Pruning channel {}/{} from network view".format(scid2, 1),
-        ])
+        l1.daemon.wait_for_log("Pruning channel {} from network view".format(scid2))
+        l2.daemon.wait_for_log("Pruning channel {} from network view".format(scid2))
 
         assert scid2 not in [c['short_channel_id'] for c in l1.rpc.listchannels()['channels']]
         assert scid2 not in [c['short_channel_id'] for c in l2.rpc.listchannels()['channels']]