Move setting signer flags to get_funding_created_msg

For all of our async signing logic in channel establishment v1, we set
signer flags in the method where we create the raw lightning message
object. To keep things consistent, this commit moves setting the signer
flags to where we create funding_created, since this was being set
elsewhere before.

While we're doing this cleanup, this also slightly refactors our
funding_signed method to move some code out of an indent, as well
as removes a log to fix a nit from #3152.

Author: alecchendev

lightning/src/ln/channel.rs

@@ -3939,38 +3939,36 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
 			&self.channel_id(), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
 
-		match &self.holder_signer {
+		// We sign "counterparty" commitment transaction, allowing them to broadcast the tx if they wish.
+		let signature = match &self.holder_signer {
 			// TODO (arik): move match into calling method for Taproot
-			ChannelSignerType::Ecdsa(ecdsa) => {
-				let funding_signed = ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.secp_ctx)
-					.map(|(signature, _)| msgs::FundingSigned {
-						channel_id: self.channel_id(),
-						signature,
-						#[cfg(taproot)]
-						partial_signature_with_nonce: None,
-					})
-					.ok();
-
-				if funding_signed.is_none() {
-					#[cfg(not(async_signing))] {
-						panic!("Failed to get signature for funding_signed");
-					}
-					#[cfg(async_signing)] {
-						log_trace!(logger, "Counterparty commitment signature not available for funding_signed message; setting signer_pending_funding");
-						self.signer_pending_funding = true;
-					}
-				} else if self.signer_pending_funding {
-					log_trace!(logger, "Counterparty commitment signature available for funding_signed message; clearing signer_pending_funding");
-					self.signer_pending_funding = false;
-				}
-
-				// We sign "counterparty" commitment transaction, allowing them to broadcast the tx if they wish.
-				funding_signed
-			},
+			ChannelSignerType::Ecdsa(ecdsa) => ecdsa.sign_counterparty_commitment(
+				&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.secp_ctx
+			).ok(),
 			// TODO (taproot|arik)
 			#[cfg(taproot)]
 			_ => todo!()
+		};
+
+		if signature.is_some() && self.signer_pending_funding {
+			log_trace!(logger, "Counterparty commitment signature available for funding_signed message; clearing signer_pending_funding");
+			self.signer_pending_funding = false;
+		} else if signature.is_none() {
+			#[cfg(not(async_signing))] {
+				panic!("Failed to get signature for funding_signed");
+			}
+			#[cfg(async_signing)] {
+				log_trace!(logger, "Counterparty commitment signature not available for funding_signed message; setting signer_pending_funding");
+				self.signer_pending_funding = true;
+			}
 		}
+
+		signature.map(|(signature, _)| msgs::FundingSigned {
+			channel_id: self.channel_id(),
+			signature,
+			#[cfg(taproot)]
+			partial_signature_with_nonce: None,
+		})
 	}
 
 	/// If we receive an error message when attempting to open a channel, it may only be a rejection
@@ -8348,19 +8346,27 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 			// TODO (taproot|arik): move match into calling method for Taproot
 			ChannelSignerType::Ecdsa(ecdsa) => {
 				ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.context.secp_ctx)
-					.map(|(sig, _)| sig).ok()?
+					.map(|(sig, _)| sig).ok()
 			},
 			// TODO (taproot|arik)
 			#[cfg(taproot)]
 			_ => todo!()
 		};
 
-		if self.context.signer_pending_funding {
+		if signature.is_some() && self.context.signer_pending_funding {
 			log_trace!(logger, "Counterparty commitment signature ready for funding_created message: clearing signer_pending_funding");
 			self.context.signer_pending_funding = false;
-		}
+		} else if signature.is_none() {
+			#[cfg(not(async_signing))] {
+				panic!("Failed to get signature for new funding creation");
+			}
+			#[cfg(async_signing)] {
+				log_trace!(logger, "funding_created awaiting signer; setting signer_pending_funding");
+				self.context.signer_pending_funding = true;
+			}
+		};
 
-		Some(msgs::FundingCreated {
+		signature.map(|signature| msgs::FundingCreated {
 			temporary_channel_id: self.context.temporary_channel_id.unwrap(),
 			funding_txid: self.context.channel_transaction_parameters.funding_outpoint.as_ref().unwrap().txid,
 			funding_output_index: self.context.channel_transaction_parameters.funding_outpoint.as_ref().unwrap().index,
@@ -8413,18 +8419,6 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 		self.context.is_batch_funding = Some(()).filter(|_| is_batch_funding);
 
 		let funding_created = self.get_funding_created_msg(logger);
-		if funding_created.is_none() {
-			#[cfg(not(async_signing))] {
-				panic!("Failed to get signature for new funding creation");
-			}
-			#[cfg(async_signing)] {
-				if !self.context.signer_pending_funding {
-					log_trace!(logger, "funding_created awaiting signer; setting signer_pending_funding");
-					self.context.signer_pending_funding = true;
-				}
-			}
-		}
-
 		Ok(funding_created)
 	}
 
@@ -8582,7 +8576,6 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 		} else { None };
 		let funding_created = if self.context.signer_pending_funding && self.context.is_outbound() {
 			log_trace!(logger, "Attempting to generate pending funding created...");
-			self.context.signer_pending_funding = false;
 			self.get_funding_created_msg(logger)
 		} else { None };
 		(open_channel, funding_created)