Fix gossipd node announcement ordering

gossipd/gossmap_manage.c

@@ -300,7 +300,7 @@ static void remove_channel(struct gossmap_manage *gm,
 
 		/* Maybe this was the last channel_announcement which preceeded node_announcement? */
 		if (chan->cann_off < node->nann_off
-		    && any_cannounce_preceeds_offset(gossmap, node, chan, node->nann_off)) {
+		    && !any_cannounce_preceeds_offset(gossmap, node, chan, node->nann_off)) {
 			const u8 *nannounce;
 			u32 timestamp;
 

lightningd/chaintopology.c

@@ -1528,6 +1528,10 @@ static void fixup_scan_block(struct bitcoind *bitcoind,
 			     struct bitcoin_block *blk,
 			     struct chain_topology *topo)
 {
+	/* Can't scan the block?  We will try again next restart */
+	if (!blk)
+		return;
+
 	log_debug(topo->ld->log, "fixup_scan: block %u with %zu txs", height, tal_count(blk->tx));
 	topo_update_spends(topo, blk->tx, blk->txids, height);
 

tests/test_gossip.py

@@ -2370,3 +2370,21 @@ def test_incoming_unreasonable(node_factory):
     wait_for(lambda: [c['updates']['remote']['fee_base_msat'] for c in l3.rpc.listpeerchannels()['channels']] == [100000000, 100000000])
     l3.restart()
     l3.rpc.listincoming()
+
+
+def test_gossmap_lost_node(node_factory, bitcoind):
+    l1, l2, l3, l4 = node_factory.line_graph(4, wait_for_announce=True)
+
+    scid23 = only_one(l2.rpc.listpeerchannels(l3.info['id'])['channels'])['short_channel_id']
+    l2.rpc.close(l3.info['id'])
+    bitcoind.generate_block(13, wait_for_mempool=1)
+    wait_for(lambda: l1.rpc.listchannels(scid23) == {'channels': []})
+
+    pre_channels = l1.rpc.listchannels()
+    pre_nodes = l1.rpc.listnodes()
+    l1.restart()
+    post_channels = l1.rpc.listchannels()
+    post_nodes = l1.rpc.listnodes()
+
+    assert post_channels == pre_channels
+    assert post_nodes == pre_nodes