Drop unreachable shutdown code in Channel::get_shutdown

`Channel` is only a thing for funded channels. Thus, checking if a
channel has not yet been funded is dead code and can simply be
elided.

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -5972,12 +5972,9 @@ impl<SP: Deref> Channel<SP> where
 
 	/// Begins the shutdown process, getting a message for the remote peer and returning all
 	/// holding cell HTLCs for payment failure.
-	///
-	/// May jump to the channel being fully shutdown (see [`Self::is_shutdown`]) in which case no
-	/// [`ChannelMonitorUpdate`] will be returned).
 	pub fn get_shutdown(&mut self, signer_provider: &SP, their_features: &InitFeatures,
 		target_feerate_sats_per_kw: Option<u32>, override_shutdown_script: Option<ShutdownScript>)
-	-> Result<(msgs::Shutdown, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>, Option<ShutdownResult>), APIError>
+	-> Result<(msgs::Shutdown, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), APIError>
 	{
 		for htlc in self.context.pending_outbound_htlcs.iter() {
 			if let OutboundHTLCState::LocalAnnounced(_) = htlc.state {
@@ -5998,16 +5995,9 @@ impl<SP: Deref> Channel<SP> where
 			return Err(APIError::ChannelUnavailable{err: "Cannot begin shutdown while peer is disconnected or we're waiting on a monitor update, maybe force-close instead?".to_owned()});
 		}
 
-		// If we haven't funded the channel yet, we don't need to bother ensuring the shutdown
-		// script is set, we just force-close and call it a day.
-		let mut chan_closed = false;
-		if self.context.channel_state.is_pre_funded_state() {
-			chan_closed = true;
-		}
-
 		let update_shutdown_script = match self.context.shutdown_scriptpubkey {
 			Some(_) => false,
-			None if !chan_closed => {
+			None => {
 				// use override shutdown script if provided
 				let shutdown_scriptpubkey = match override_shutdown_script {
 					Some(script) => script,
@@ -6025,25 +6015,11 @@ impl<SP: Deref> Channel<SP> where
 				self.context.shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
 				true
 			},
-			None => false,
 		};
 
 		// From here on out, we may not fail!
 		self.context.target_closing_feerate_sats_per_kw = target_feerate_sats_per_kw;
-		let shutdown_result = if self.context.channel_state.is_pre_funded_state() {
-			let shutdown_result = ShutdownResult {
-				monitor_update: None,
-				dropped_outbound_htlcs: Vec::new(),
-				unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
-				channel_id: self.context.channel_id,
-				counterparty_node_id: self.context.counterparty_node_id,
-			};
-			self.context.channel_state = ChannelState::ShutdownComplete;
-			Some(shutdown_result)
-		} else {
-			self.context.channel_state.set_local_shutdown_sent();
-			None
-		};
+		self.context.channel_state.set_local_shutdown_sent();
 		self.context.update_time_counter += 1;
 
 		let monitor_update = if update_shutdown_script {
@@ -6079,7 +6055,7 @@ impl<SP: Deref> Channel<SP> where
 		debug_assert!(!self.is_shutdown() || monitor_update.is_none(),
 			"we can't both complete shutdown and return a monitor update");
 
-		Ok((shutdown, monitor_update, dropped_outbound_htlcs, shutdown_result))
+		Ok((shutdown, monitor_update, dropped_outbound_htlcs))
 	}
 
 	pub fn inflight_htlc_sources(&self) -> impl Iterator<Item=(&HTLCSource, &PaymentHash)> {

lightning/src/ln/channelmanager.rs

@@ -2730,10 +2730,10 @@ where
 					if let ChannelPhase::Funded(chan) = chan_phase_entry.get_mut() {
 						let funding_txo_opt = chan.context.get_funding_txo();
 						let their_features = &peer_state.latest_features;
-						let (shutdown_msg, mut monitor_update_opt, htlcs, local_shutdown_result) =
+						let (shutdown_msg, mut monitor_update_opt, htlcs) =
 							chan.get_shutdown(&self.signer_provider, their_features, target_feerate_sats_per_1000_weight, override_shutdown_script)?;
 						failed_htlcs = htlcs;
-						shutdown_result = local_shutdown_result;
+						shutdown_result = None;
 						debug_assert_eq!(shutdown_result.is_some(), chan.is_shutdown());
 
 						// We can send the `shutdown` message before updating the `ChannelMonitor`