Introduce new code changes properly handling this new behavior

- Do not remove channel immediately when peer_disconnect, instead
  removed it after some time if peer doesn't reconnect soon (handled in
previous commit).
- Do not mark per ok_to_remove if we have some OutboundV1Channels too.
- Rebroadcast SendOpenChannel for outboundV1Channel when peer
  reconnects.

Author: shaavan

lightning/src/ln/channelmanager.rs

@@ -874,6 +874,7 @@ impl <SP: Deref> PeerState<SP> where SP::Target: SignerProvider {
 			return false
 		}
 		self.channel_by_id.iter().filter(|(_, phase)| matches!(phase, ChannelPhase::Funded(_))).count() == 0
+			&& self.channel_by_id.iter().filter(|(_, phase)| matches!(phase, ChannelPhase::UnfundedOutboundV1(_))).count() == 0
 			&& self.monitor_update_blocked_actions.is_empty()
 			&& self.in_flight_monitor_updates.is_empty()
 	}
@@ -8730,10 +8731,12 @@ where
 							}
 							&mut chan.context
 						},
-						// Unfunded channels will always be removed.
-						ChannelPhase::UnfundedOutboundV1(chan) => {
-							&mut chan.context
+						// We retain UnfundedOutboundV1 channel for some time in case
+						// peer unexpectedly disconnects, and intends to reconnect again.
+						ChannelPhase::UnfundedOutboundV1(_) => {
+							return true;
 						},
+						// Unfunded inbound channels will always be removed.
 						ChannelPhase::UnfundedInboundV1(chan) => {
 							&mut chan.context
 						},
@@ -8873,21 +8876,27 @@ where
 				let peer_state = &mut *peer_state_lock;
 				let pending_msg_events = &mut peer_state.pending_msg_events;
 
-				peer_state.channel_by_id.iter_mut().filter_map(|(_, phase)|
-					if let ChannelPhase::Funded(chan) = phase { Some(chan) } else {
-						// Since unfunded channel maps are cleared upon disconnecting a peer, and they're not persisted
-						// (so won't be recovered after a crash), they shouldn't exist here and we would never need to
-						// worry about closing and removing them.
+				for (_, phase) in peer_state.channel_by_id.iter_mut() {
+					if let ChannelPhase::Funded(chan) = phase {
+						let logger = WithChannelContext::from(&self.logger, &chan.context);
+						pending_msg_events.push(events::MessageSendEvent::SendChannelReestablish {
+							node_id: chan.context.get_counterparty_node_id(),
+							msg: chan.get_channel_reestablish(&&logger),
+						});
+					}
+					else if let ChannelPhase::UnfundedOutboundV1(chan) = phase {
+						pending_msg_events.push(events::MessageSendEvent::SendOpenChannel {
+							node_id: chan.context.get_counterparty_node_id(),
+							msg: chan.get_open_channel(self.chain_hash),
+						});
+					}
+					else {
+						// Since unfunded inbound channel maps are cleared upon disconnecting a peer, and they're not
+						// persisted (so won't be recovered after a crash), they shouldn't exist here and we would never
+						// need to worry about closing and removing them.
 						debug_assert!(false);
-						None
 					}
-				).for_each(|chan| {
-					let logger = WithChannelContext::from(&self.logger, &chan.context);
-					pending_msg_events.push(events::MessageSendEvent::SendChannelReestablish {
-						node_id: chan.context.get_counterparty_node_id(),
-						msg: chan.get_channel_reestablish(&&logger),
-					});
-				});
+				}
 			}
 
 			return NotifyOption::SkipPersistHandleEvents;