f - don't set shutdown state if waiting on signature

Author: alecchendev

lightning/src/ln/channel.rs

@@ -6168,13 +6168,8 @@ impl<SP: Deref> Channel<SP> where
 		-> Result<(Option<msgs::ClosingSigned>, Option<Transaction>, Option<ShutdownResult>), ChannelError>
 		where F::Target: FeeEstimator, L::Target: Logger
 	{
-		if matches!(self.context.channel_state, ChannelState::ShutdownComplete) {
-			// During async signing, we may need to keep the channel around
-			// even after it's been fully closed, so that we can construct
-			// and sign the final transaction to send back to the peer.
-			// If they send us another closing_signed, we should act as
-			// if the channel has already been fully closed.
-			return Err(ChannelError::Warn(String::from("Remote end sent us a closing_signed after shutdown complete")));
+		if self.is_shutdown_pending_signature() {
+			return Err(ChannelError::Warn(String::from("Remote end sent us a closing_signed while fully shutdown and just waiting on the final closing signature")));
 		}
 		if !self.context.channel_state.is_both_sides_shutdown() {
 			return Err(ChannelError::close("Remote end sent us a closing_signed before both sides provided a shutdown".to_owned()));
@@ -6277,7 +6272,9 @@ impl<SP: Deref> Channel<SP> where
 						unbroadcasted_funding_tx: self.context.unbroadcasted_funding(),
 						channel_funding_txo: self.context.get_funding_txo(),
 					};
-					self.context.channel_state = ChannelState::ShutdownComplete;
+					if closing_signed.is_some() {
+						self.context.channel_state = ChannelState::ShutdownComplete;
+					}
 					self.context.update_time_counter += 1;
 					self.context.last_received_closing_sig = Some(msg.signature.clone());
 					let tx = closing_signed.as_ref().map(|ClosingSigned { signature, .. }|
@@ -6640,6 +6637,12 @@ impl<SP: Deref> Channel<SP> where
 		matches!(self.context.channel_state, ChannelState::ShutdownComplete)
 	}
 
+	pub fn is_shutdown_pending_signature(&self) -> bool {
+		matches!(self.context.channel_state, ChannelState::ChannelReady(_))
+			&& self.context.signer_pending_closing
+			&& self.context.last_received_closing_sig.is_some()
+	}
+
 	pub fn channel_update_status(&self) -> ChannelUpdateStatus {
 		self.context.channel_update_status
 	}

lightning/src/ln/channelmanager.rs

@@ -7795,7 +7795,7 @@ where
 					if let ChannelPhase::Funded(chan) = chan_phase_entry.get_mut() {
 						let logger = WithChannelContext::from(&self.logger, &chan.context, None);
 						let (closing_signed, tx, shutdown_result) = try_chan_phase_entry!(self, chan.closing_signed(&self.fee_estimator, &msg, &&logger), chan_phase_entry);
-						debug_assert_eq!(shutdown_result.is_some(), chan.is_shutdown());
+						debug_assert_eq!(shutdown_result.is_some(), chan.is_shutdown() || chan.is_shutdown_pending_signature());
 						if let Some(msg) = closing_signed {
 							peer_state.pending_msg_events.push(events::MessageSendEvent::SendClosingSigned {
 								node_id: counterparty_node_id.clone(),
@@ -8739,7 +8739,7 @@ where
 										});
 									}
 									if let Some(shutdown_result) = shutdown_result_opt {
-										debug_assert!(chan.is_shutdown());
+										debug_assert!(chan.is_shutdown() || chan.is_shutdown_pending_signature());
 										shutdown_results.push(shutdown_result);
 									}
 									if let Some(tx) = tx_opt {