Drop error type parameter from SignError

SignError allows implementors of SignFunction to return a custom error
type. Drop this as an unconstrained type causes problems with bindings
and isn't useful unless the caller can take some sort of action based on
different errors.

fuzz/src/invoice_request_deser.rs

@@ -9,7 +9,7 @@
 
 use bitcoin::secp256k1::{KeyPair, Parity, PublicKey, Secp256k1, SecretKey, self};
 use crate::utils::test_logger;
-use core::convert::{Infallible, TryFrom};
+use core::convert::TryFrom;
 use lightning::blinded_path::BlindedPath;
 use lightning::sign::EntropySource;
 use lightning::ln::PaymentHash;
@@ -37,17 +37,17 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
 			let even_pubkey = x_only_pubkey.public_key(Parity::Even);
 			if signing_pubkey == odd_pubkey || signing_pubkey == even_pubkey {
 				unsigned_invoice
-					.sign(|message: &UnsignedBolt12Invoice| -> Result<_, Infallible> {
+					.sign(|message: &UnsignedBolt12Invoice|
 						Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-					})
+					)
 					.unwrap()
 					.write(&mut buffer)
 					.unwrap();
 			} else {
 				unsigned_invoice
-					.sign(|message: &UnsignedBolt12Invoice| -> Result<_, Infallible> {
+					.sign(|message: &UnsignedBolt12Invoice|
 						Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-					})
+					)
 					.unwrap_err();
 			}
 		}

fuzz/src/offer_deser.rs

@@ -9,7 +9,7 @@
 
 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
 use crate::utils::test_logger;
-use core::convert::{Infallible, TryFrom};
+use core::convert::TryFrom;
 use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::offers::offer::{Amount, Offer, Quantity};
 use lightning::offers::parse::Bolt12SemanticError;
@@ -29,9 +29,9 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
 
 		if let Ok(invoice_request) = build_response(&offer, pubkey) {
 			invoice_request
-				.sign(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+				.sign(|message: &UnsignedInvoiceRequest|
 					Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-				})
+				)
 				.unwrap()
 				.write(&mut buffer)
 				.unwrap();

fuzz/src/refund_deser.rs

@@ -9,7 +9,7 @@
 
 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey, self};
 use crate::utils::test_logger;
-use core::convert::{Infallible, TryFrom};
+use core::convert::TryFrom;
 use lightning::blinded_path::BlindedPath;
 use lightning::sign::EntropySource;
 use lightning::ln::PaymentHash;
@@ -33,9 +33,9 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
 
 		if let Ok(invoice) = build_response(&refund, pubkey, &secp_ctx) {
 			invoice
-				.sign(|message: &UnsignedBolt12Invoice| -> Result<_, Infallible> {
+				.sign(|message: &UnsignedBolt12Invoice|
 					Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-				})
+				)
 				.unwrap()
 				.write(&mut buffer)
 				.unwrap();

lightning/src/ln/channelmanager.rs

@@ -9306,7 +9306,7 @@ where
 								self.node_signer.sign_bolt12_invoice(invoice)
 							) {
 								Ok(invoice) => Ok(OffersMessage::Invoice(invoice)),
-								Err(SignError::Signing(())) => Err(OffersMessage::InvoiceError(
+								Err(SignError::Signing) => Err(OffersMessage::InvoiceError(
 										InvoiceError::from_string("Failed signing invoice".to_string())
 								)),
 								Err(SignError::Verification(_)) => Err(OffersMessage::InvoiceError(

lightning/src/offers/invoice.rs

@@ -22,7 +22,7 @@
 //!
 //! use bitcoin::hashes::Hash;
 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
-//! use core::convert::{Infallible, TryFrom};
+//! use core::convert::TryFrom;
 //! use lightning::offers::invoice::UnsignedBolt12Invoice;
 //! use lightning::offers::invoice_request::InvoiceRequest;
 //! use lightning::offers::refund::Refund;
@@ -58,9 +58,9 @@
 //!     .allow_mpp()
 //!     .fallback_v0_p2wpkh(&wpubkey_hash)
 //!     .build()?
-//!     .sign(|message: &UnsignedBolt12Invoice| -> Result<_, Infallible> {
+//!     .sign(|message: &UnsignedBolt12Invoice|
 //!         Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-//!     })
+//!     )
 //!     .expect("failed verifying signature")
 //!     .write(&mut buffer)
 //!     .unwrap();
@@ -91,9 +91,9 @@
 //!     .allow_mpp()
 //!     .fallback_v0_p2wpkh(&wpubkey_hash)
 //!     .build()?
-//!     .sign(|message: &UnsignedBolt12Invoice| -> Result<_, Infallible> {
+//!     .sign(|message: &UnsignedBolt12Invoice|
 //!         Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-//!     })
+//!     )
 //!     .expect("failed verifying signature")
 //!     .write(&mut buffer)
 //!     .unwrap();
@@ -110,7 +110,7 @@ use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
 use bitcoin::secp256k1::schnorr::Signature;
 use bitcoin::address::{Address, Payload, WitnessProgram, WitnessVersion};
 use bitcoin::key::TweakedPublicKey;
-use core::convert::{AsRef, Infallible, TryFrom};
+use core::convert::{AsRef, TryFrom};
 use core::time::Duration;
 use crate::io;
 use crate::blinded_path::BlindedPath;
@@ -325,9 +325,9 @@ macro_rules! invoice_derived_signing_pubkey_builder_methods { ($self: ident, $se
 		let mut unsigned_invoice = UnsignedBolt12Invoice::new(invreq_bytes, invoice.clone());
 
 		let invoice = unsigned_invoice
-			.sign(|message: &UnsignedBolt12Invoice| -> Result<_, Infallible> {
+			.sign(|message: &UnsignedBolt12Invoice|
 				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-			})
+			)
 			.unwrap();
 		Ok(invoice)
 	}
@@ -510,31 +510,24 @@ pub struct UnsignedBolt12Invoice {
 
 /// A function for signing an [`UnsignedBolt12Invoice`].
 pub trait SignBolt12InvoiceFn {
-	/// Error type returned by the function.
-	type Error;
-
 	/// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream.
-	fn sign_invoice(&self, message: &UnsignedBolt12Invoice) -> Result<Signature, Self::Error>;
+	fn sign_invoice(&self, message: &UnsignedBolt12Invoice) -> Result<Signature, ()>;
 }
 
-impl<F, E> SignBolt12InvoiceFn for F
+impl<F> SignBolt12InvoiceFn for F
 where
-	F: Fn(&UnsignedBolt12Invoice) -> Result<Signature, E>,
+	F: Fn(&UnsignedBolt12Invoice) -> Result<Signature, ()>,
 {
-	type Error = E;
-
-	fn sign_invoice(&self, message: &UnsignedBolt12Invoice) -> Result<Signature, E> {
+	fn sign_invoice(&self, message: &UnsignedBolt12Invoice) -> Result<Signature, ()> {
 		self(message)
 	}
 }
 
-impl<F, E> SignFn<UnsignedBolt12Invoice> for F
+impl<F> SignFn<UnsignedBolt12Invoice> for F
 where
-	F: SignBolt12InvoiceFn<Error = E>,
+	F: SignBolt12InvoiceFn,
 {
-	type Error = E;
-
-	fn sign(&self, message: &UnsignedBolt12Invoice) -> Result<Signature, Self::Error> {
+	fn sign(&self, message: &UnsignedBolt12Invoice) -> Result<Signature, ()> {
 		self.sign_invoice(message)
 	}
 }
@@ -568,7 +561,7 @@ macro_rules! unsigned_invoice_sign_method { ($self: ident, $self_type: ty $(, $s
 	/// Note: The hash computation may have included unknown, odd TLV records.
 	pub fn sign<F: SignBolt12InvoiceFn>(
 		$($self_mut)* $self: $self_type, sign: F
-	) -> Result<Bolt12Invoice, SignError<F::Error>> {
+	) -> Result<Bolt12Invoice, SignError> {
 		let pubkey = $self.contents.fields().signing_pubkey;
 		let signature = merkle::sign_message(sign, &$self, pubkey)?;
 
@@ -2045,7 +2038,7 @@ mod tests {
 			.sign(fail_sign)
 		{
 			Ok(_) => panic!("expected error"),
-			Err(e) => assert_eq!(e, SignError::Signing(())),
+			Err(e) => assert_eq!(e, SignError::Signing),
 		}
 
 		match OfferBuilder::new("foo".into(), recipient_pubkey())

lightning/src/offers/invoice_request.rs

@@ -25,7 +25,6 @@
 //!
 //! use bitcoin::network::constants::Network;
 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
-//! use core::convert::Infallible;
 //! use lightning::ln::features::OfferFeatures;
 //! use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 //! use lightning::offers::offer::Offer;
@@ -48,9 +47,9 @@
 //!     .quantity(5)?
 //!     .payer_note("foo".to_string())
 //!     .build()?
-//!     .sign(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+//!     .sign(|message: &UnsignedInvoiceRequest|
 //!         Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-//!     })
+//!     )
 //!     .expect("failed verifying signature")
 //!     .write(&mut buffer)
 //!     .unwrap();
@@ -62,7 +61,7 @@ use bitcoin::blockdata::constants::ChainHash;
 use bitcoin::network::constants::Network;
 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
 use bitcoin::secp256k1::schnorr::Signature;
-use core::convert::{AsRef, Infallible, TryFrom};
+use core::convert::{AsRef, TryFrom};
 use core::ops::Deref;
 use crate::sign::EntropySource;
 use crate::io;
@@ -228,9 +227,9 @@ macro_rules! invoice_request_derived_payer_id_builder_methods { (
 		let secp_ctx = secp_ctx.unwrap();
 		let keys = keys.unwrap();
 		let invoice_request = unsigned_invoice_request
-			.sign(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+			.sign(|message: &UnsignedInvoiceRequest|
 				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-			})
+			)
 			.unwrap();
 		Ok(invoice_request)
 	}
@@ -496,31 +495,24 @@ pub struct UnsignedInvoiceRequest {
 
 /// A function for signing an [`UnsignedInvoiceRequest`].
 pub trait SignInvoiceRequestFn {
-	/// Error type returned by the function.
-	type Error;
-
 	/// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream.
-	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, Self::Error>;
+	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()>;
 }
 
-impl<F, E> SignInvoiceRequestFn for F
+impl<F> SignInvoiceRequestFn for F
 where
-	F: Fn(&UnsignedInvoiceRequest) -> Result<Signature, E>,
+	F: Fn(&UnsignedInvoiceRequest) -> Result<Signature, ()>,
 {
-	type Error = E;
-
-	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, E> {
+	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()> {
 		self(message)
 	}
 }
 
-impl<F, E> SignFn<UnsignedInvoiceRequest> for F
+impl<F> SignFn<UnsignedInvoiceRequest> for F
 where
-	F: SignInvoiceRequestFn<Error = E>,
+	F: SignInvoiceRequestFn,
 {
-	type Error = E;
-
-	fn sign(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, Self::Error> {
+	fn sign(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()> {
 		self.sign_invoice_request(message)
 	}
 }
@@ -556,7 +548,7 @@ macro_rules! unsigned_invoice_request_sign_method { (
 	/// Note: The hash computation may have included unknown, odd TLV records.
 	pub fn sign<F: SignInvoiceRequestFn>(
 		$($self_mut)* $self: $self_type, sign: F
-	) -> Result<InvoiceRequest, SignError<F::Error>> {
+	) -> Result<InvoiceRequest, SignError> {
 		let pubkey = $self.contents.payer_id;
 		let signature = merkle::sign_message(sign, &$self, pubkey)?;
 
@@ -1111,7 +1103,7 @@ mod tests {
 	use bitcoin::blockdata::constants::ChainHash;
 	use bitcoin::network::constants::Network;
 	use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey, self};
-	use core::convert::{Infallible, TryFrom};
+	use core::convert::TryFrom;
 	use core::num::NonZeroU64;
 	#[cfg(feature = "std")]
 	use core::time::Duration;
@@ -1744,7 +1736,7 @@ mod tests {
 			.sign(fail_sign)
 		{
 			Ok(_) => panic!("expected error"),
-			Err(e) => assert_eq!(e, SignError::Signing(())),
+			Err(e) => assert_eq!(e, SignError::Signing),
 		}
 
 		match OfferBuilder::new("foo".into(), recipient_pubkey())
@@ -2155,9 +2147,9 @@ mod tests {
 			.build().unwrap()
 			.request_invoice(vec![1; 32], keys.public_key()).unwrap()
 			.build().unwrap()
-			.sign(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+			.sign(|message: &UnsignedInvoiceRequest|
 				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-			})
+			)
 			.unwrap();
 
 		let mut encoded_invoice_request = Vec::new();