f fix the some-connected-some-sufficient no-overlap issue

Author: TheBlueMatt

lightning-invoice/src/utils.rs

@@ -386,6 +386,7 @@ fn filter_channels(channels: Vec<ChannelDetails>, min_inbound_capacity_msat: Opt
 	let min_inbound_capacity = min_inbound_capacity_msat.unwrap_or(0);
 	let mut min_capacity_channel_exists = false;
 	let mut online_channel_exists = false;
+	let mut online_min_capacity_channel_exists = false;
 
 	for channel in channels.into_iter().filter(|chan| chan.is_channel_ready) {
 		if channel.get_inbound_payment_scid().is_none() || channel.counterparty.forwarding_info.is_none() {
@@ -400,7 +401,10 @@ fn filter_channels(channels: Vec<ChannelDetails>, min_inbound_capacity_msat: Opt
 
 		if channel.inbound_capacity_msat >= min_inbound_capacity {
 			min_capacity_channel_exists = true;
-		};
+			if channel.is_usable {
+				online_min_capacity_channel_exists = true;
+			}
+		}
 		if channel.is_usable {
 			online_channel_exists = true;
 		}
@@ -437,12 +441,16 @@ fn filter_channels(channels: Vec<ChannelDetails>, min_inbound_capacity_msat: Opt
 	// Further, if we are connected to our peer for any channels, only return those.
 	filtered_channels.into_iter()
 		.filter(|(_counterparty_id, channel)| {
-			if min_capacity_channel_exists {
+			if online_min_capacity_channel_exists {
+				channel.inbound_capacity_msat >= min_inbound_capacity && channel.is_usable
+			} else if min_capacity_channel_exists && online_channel_exists {
+				// If there are some online channels and some min_capacity channels, but no
+				// online-and-min_capacity channels, just include the min capacity ones and ignore
+				// online-ness.
 				channel.inbound_capacity_msat >= min_inbound_capacity
-			} else { true }
-		})
-		.filter(|(_counterparty_id, channel)| {
-			if online_channel_exists {
+			} else if min_capacity_channel_exists {
+				channel.inbound_capacity_msat >= min_inbound_capacity
+			} else if online_channel_exists {
 				channel.is_usable
 			} else { true }
 		})
@@ -736,29 +744,31 @@ mod test {
 
 	#[test]
 	fn test_hints_has_only_online_channels() {
-		let chanmon_cfgs = create_chanmon_cfgs(3);
-		let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
-		let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
-		let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+		let chanmon_cfgs = create_chanmon_cfgs(4);
+		let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+		let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+		let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
 		let chan_a = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 10_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
 		let chan_b = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 0, 10_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
+		let _chan_c = create_unannounced_chan_between_nodes_with_value(&nodes, 3, 0, 1_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
 
-		// With both peers connected we should get all hints
+		// With all peers connected we should get all hints that have sufficient value
 		let mut scid_aliases = HashSet::new();
 		scid_aliases.insert(chan_a.0.short_channel_id_alias.unwrap());
 		scid_aliases.insert(chan_b.0.short_channel_id_alias.unwrap());
 
-		match_invoice_routes(Some(5000), &nodes[0], scid_aliases.clone());
+		match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases.clone());
 
-		// With only one peer connected other hints should go away
+		// With only one sufficient-value peer connected we should only get its hint
 		scid_aliases.remove(&chan_b.0.short_channel_id_alias.unwrap());
 		nodes[0].node.peer_disconnected(&nodes[2].node.get_our_node_id(), false);
-		match_invoice_routes(Some(5000), &nodes[0], scid_aliases.clone());
+		match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases.clone());
 
-		// With both peers disconnected we should just get all the hints
+		// If we don't have any sufficient-value peers connected we should get all hints with
+		// sufficient value, even though there is a conencted insufficient-value peer.
 		scid_aliases.insert(chan_b.0.short_channel_id_alias.unwrap());
 		nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id(), false);
-		match_invoice_routes(Some(5000), &nodes[0], scid_aliases);
+		match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases);
 	}
 
 	#[test]