Explicit error message when disconnect fails

Whether the peer is not connected or not gossiping.

gossipd/gossip.c

@@ -1029,8 +1029,8 @@ static struct io_plan *disconnect_peer(struct io_conn *conn, struct daemon *daem
 	} else {
 		status_trace("disconnect_peer: peer %s %s",
 			     type_to_string(trc, struct pubkey, &id),
-			     !peer ? "not found" : "not local to this daemon");
-		msg = towire_gossipctl_peer_disconnect_replyfail(msg);
+			     !peer ? "not connected" : "not gossiping");
+		msg = towire_gossipctl_peer_disconnect_replyfail(msg, peer ? true : false);
 		daemon_conn_send(&daemon->master, take(msg));
 	}
 	return daemon_conn_read_next(conn, &daemon->master);

gossipd/gossip_wire.csv

@@ -222,3 +222,4 @@ gossipctl_peer_disconnect_reply,3123
 
 # Gossipd -> master:  reply to gossip_peer_disconnect if we couldn't find the peer.
 gossipctl_peer_disconnect_replyfail,3223
+gossipctl_peer_disconnect_replyfail,,isconnected,bool

lightningd/peer_control.c

@@ -880,11 +880,16 @@ static void gossip_peer_disconnected (struct subd *gossip,
 				 const u8 *resp,
 				 const int *fds,
 				 struct command *cmd) {
+	bool isconnected;
+
 	if (!fromwire_gossipctl_peer_disconnect_reply(resp)) {
-		if (!fromwire_gossipctl_peer_disconnect_replyfail(resp))
+		if (!fromwire_gossipctl_peer_disconnect_replyfail(resp, &isconnected))
 			fatal("Gossip daemon gave invalid reply %s",
 			      tal_hex(gossip, resp));
-		command_fail(cmd, "Peer not connected");
+		if (isconnected)
+			command_fail(cmd, "Peer is not in gossip mode");
+		else
+			command_fail(cmd, "Peer not connected");
 	} else {
 		/* Successfully disconnected */
 		command_success(cmd, null_response(cmd));

tests/test_lightningd.py

@@ -3821,15 +3821,18 @@ class LightningDTests(BaseLightningDTests):
         assert l2.rpc.getpeer(l1.info['id']) is None
 
         # Make sure you cannot disconnect after disconnecting
-        self.assertRaises(ValueError, l1.rpc.disconnect, l2.info['id'])
-        self.assertRaises(ValueError, l2.rpc.disconnect, l1.info['id'])
+        self.assertRaisesRegex(ValueError, "Peer not connected",
+                               l1.rpc.disconnect, l2.info['id'])
+        self.assertRaisesRegex(ValueError, "Peer not connected",
+                               l2.rpc.disconnect, l1.info['id'])
 
         # Fund channel l1 -> l3
         self.fund_channel(l1, l3, 10**6)
         bitcoind.generate_block(5)
 
         # disconnecting a non gossiping peer results in error
-        self.assertRaises(ValueError, l1.rpc.disconnect, l3.info['id'])
+        self.assertRaisesRegex(ValueError, "Peer is not in gossip mode",
+                               l1.rpc.disconnect, l3.info['id'])
 
 
 if __name__ == '__main__':

wallet/test/run-wallet.c

@@ -383,7 +383,7 @@ u8 *towire_gossipctl_peer_disconnect(const tal_t *ctx UNNEEDED, const struct pub
 bool fromwire_gossipctl_peer_disconnect_reply(const void *p UNNEEDED)
 { fprintf(stderr, "fromwire_gossipctl_peer_disconnect_reply called!\n"); abort(); }
 /* Generated stub for fromwire_gossipctl_peer_disconnect_replyfail*/
-bool fromwire_gossipctl_peer_disconnect_replyfail(const void *p UNNEEDED)
+bool fromwire_gossipctl_peer_disconnect_replyfail(const void *p UNNEEDED, bool *isconnected UNNEEDED)
 { fprintf(stderr, "fromwire_gossipctl_peer_disconnect_replyfail called!\n"); abort(); }
 /* AUTOGENERATED MOCKS END */