Reparametrize ChannelSignerType by SignerProvider.

ChannelSignerType is an enum that contains variants of all currently
supported signer types. Given that those signer types are enumerated
as associated types in multiple places, it is prudent to denote one
type as the authority on signer types.

SignerProvider seemed like the best option. Thus, instead of
ChannelSignerType declaring the associated types itself, it simply
uses their definitions from SignerProvider.

Author: arik-so

lightning/src/ln/channel.rs

@@ -664,7 +664,7 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
 
 	latest_monitor_update_id: u64,
 
-	holder_signer: ChannelSignerType<<SP::Target as SignerProvider>::EcdsaSigner>,
+	holder_signer: ChannelSignerType<SP>,
 	shutdown_scriptpubkey: Option<ShutdownScript>,
 	destination_script: Script,
 
@@ -3261,7 +3261,9 @@ impl<SP: Deref> Channel<SP> where
 					self.context.cur_counterparty_commitment_transaction_number + 1,
 					&secret
 				).map_err(|_| ChannelError::Close("Failed to validate revocation from peer".to_owned()))?;
-			}
+			},
+			// TODO (taproot|arik)
+			_ => todo!()
 		};
 
 		self.context.commitment_secrets.provide_secret(self.context.cur_counterparty_commitment_transaction_number + 1, msg.per_commitment_secret)
@@ -4152,7 +4154,9 @@ impl<SP: Deref> Channel<SP> where
 						max_fee_satoshis: our_max_fee,
 					}),
 				}), None))
-			}
+			},
+			// TODO (taproot|arik)
+			_ => todo!()
 		}
 	}
 
@@ -4392,7 +4396,9 @@ impl<SP: Deref> Channel<SP> where
 								max_fee_satoshis: our_max_fee,
 							}),
 						}), signed_tx))
-					}
+					},
+					// TODO (taproot|arik)
+					_ => todo!()
 				}
 			}
 		}
@@ -4504,7 +4510,7 @@ impl<SP: Deref> Channel<SP> where
 	}
 
 	#[cfg(test)]
-	pub fn get_signer(&self) -> &ChannelSignerType<<SP::Target as SignerProvider>::EcdsaSigner> {
+	pub fn get_signer(&self) -> &ChannelSignerType<SP> {
 		&self.context.holder_signer
 	}
 
@@ -5014,7 +5020,9 @@ impl<SP: Deref> Channel<SP> where
 					node_signature: our_node_sig,
 					bitcoin_signature: our_bitcoin_sig,
 				})
-			}
+			},
+			// TODO (taproot|arik)
+			_ => todo!()
 		}
 	}
 
@@ -5041,7 +5049,9 @@ impl<SP: Deref> Channel<SP> where
 						bitcoin_signature_2: if were_node_one { their_bitcoin_sig } else { our_bitcoin_sig },
 						contents: announcement,
 					})
-				}
+				},
+				// TODO (taproot|arik)
+				_ => todo!()
 			}
 		} else {
 			Err(ChannelError::Ignore("Attempted to sign channel announcement before we'd received announcement_signatures".to_string()))
@@ -5414,7 +5424,9 @@ impl<SP: Deref> Channel<SP> where
 					#[cfg(taproot)]
 					partial_signature_with_nonce: None,
 				}, (counterparty_commitment_txid, commitment_stats.htlcs_included)))
-			}
+			},
+			// TODO (taproot|arik)
+			_ => todo!()
 		}
 	}
 
@@ -5790,7 +5802,9 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 			ChannelSignerType::Ecdsa(ecdsa) => {
 				Ok(ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.context.secp_ctx)
 					.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0)
-			}
+			},
+			// TODO (taproot|arik)
+			_ => todo!()
 		}
 	}
 
@@ -6529,6 +6543,8 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 				// We sign "counterparty" commitment transaction, allowing them to broadcast the tx if they wish.
 				Ok((counterparty_initial_commitment_tx, initial_commitment_tx, counterparty_signature))
 			}
+			// TODO (taproot|arik)
+			_ => todo!()
 		}
 	}
 

lightning/src/sign/taproot.rs

@@ -1,5 +1,6 @@
 //! Defines a Taproot-specific signer type.
 
+use alloc::vec::Vec;
 use bitcoin::blockdata::transaction::Transaction;
 use bitcoin::secp256k1;
 use bitcoin::secp256k1::{PublicKey, schnorr::Signature, Secp256k1, SecretKey};

lightning/src/sign/type_resolver.rs

@@ -1,32 +1,41 @@
-use crate::sign::{ChannelSigner, EcdsaChannelSigner};
+use core::ops::Deref;
+use crate::sign::{ChannelSigner, SignerProvider};
 
-pub(crate) enum ChannelSignerType<ECS: EcdsaChannelSigner> {
+pub(crate) enum ChannelSignerType<SP: Deref> where SP::Target: SignerProvider {
 	// in practice, this will only ever be an EcdsaChannelSigner (specifically, Writeable)
-	Ecdsa(ECS)
+	Ecdsa(<SP::Target as SignerProvider>::EcdsaSigner),
+	#[cfg(taproot)]
+	Taproot(<SP::Target as SignerProvider>::TaprootSigner),
 }
 
-impl<ECS: EcdsaChannelSigner> ChannelSignerType<ECS>{
+impl<SP: Deref> ChannelSignerType<SP> where SP::Target: SignerProvider {
 	pub(crate) fn as_ref(&self) -> &dyn ChannelSigner {
 		match self {
-			ChannelSignerType::Ecdsa(ecs) => ecs
+			ChannelSignerType::Ecdsa(ecs) => ecs,
+			#[cfg(taproot)]
+			ChannelSignerType::Taproot(tcs) => tcs,
 		}
 	}
 
 	pub(crate) fn as_mut(&mut self) -> &mut dyn ChannelSigner {
 		match self {
-			ChannelSignerType::Ecdsa(ecs) => ecs
+			ChannelSignerType::Ecdsa(ecs) => ecs,
+			#[cfg(taproot)]
+			ChannelSignerType::Taproot(tcs) => tcs,
 		}
 	}
 
-	pub(crate) fn as_ecdsa(&self) -> Option<&ECS> {
+	pub(crate) fn as_ecdsa(&self) -> Option<&<SP::Target as SignerProvider>::EcdsaSigner> {
 		match self {
-			ChannelSignerType::Ecdsa(ecs) => Some(ecs)
+			ChannelSignerType::Ecdsa(ecs) => Some(ecs),
+			_ => None
 		}
 	}
 
-	pub(crate) fn as_mut_ecdsa(&mut self) -> Option<&mut ECS> {
+	pub(crate) fn as_mut_ecdsa(&mut self) -> Option<&mut <SP::Target as SignerProvider>::EcdsaSigner> {
 		match self {
-			ChannelSignerType::Ecdsa(ecs) => Some(ecs)
+			ChannelSignerType::Ecdsa(ecs) => Some(ecs),
+			_ => None
 		}
 	}
 }