Use SemanticError in OfferBuilder::build

Author: jkczyz

lightning/src/offers/offer.rs

@@ -48,8 +48,7 @@
 //!     .issuer("Foo Bar".to_string())
 //!     .path(create_blinded_path())
 //!     .path(create_another_blinded_path())
-//!     .build()
-//!     .unwrap();
+//!     .build()?;
 //!
 //! // Encode as a bech32 string for use in a QR code.
 //! let encoded_offer = offer.to_string();
@@ -189,11 +188,11 @@ impl OfferBuilder {
 	}
 
 	/// Builds an [`Offer`] from the builder's settings.
-	pub fn build(self) -> Result<Offer, ()> {
+	pub fn build(self) -> Result<Offer, SemanticError> {
 		// TODO: Also check for Amount::Currency
 		if let Some(Amount::Currency { .. }) = self.offer.amount {
 		} else if self.offer.amount_msats() > MAX_VALUE_MSAT {
-			return Err(());
+			return Err(SemanticError::InvalidAmount);
 		}
 
 		let mut bytes = Vec::new();
@@ -550,6 +549,7 @@ mod tests {
 	use core::time::Duration;
 	use crate::ln::features::OfferFeatures;
 	use crate::ln::msgs::MAX_VALUE_MSAT;
+	use crate::offers::parse::SemanticError;
 	use crate::onion_message::{BlindedHop, BlindedPath};
 	use crate::util::ser::Writeable;
 	use crate::util::string::PrintableString;
@@ -686,7 +686,7 @@ mod tests {
 		let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
 		match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
 			Ok(_) => panic!("expected error"),
-			Err(e) => assert_eq!(e, ()),
+			Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
 		}
 	}
 

lightning/src/offers/parse.rs

@@ -74,6 +74,8 @@ pub enum ParseError {
 pub enum SemanticError {
 	/// An amount was expected but was missing.
 	MissingAmount,
+	/// An amount exceeded the maximum number of bitcoin.
+	InvalidAmount,
 	/// A required description was not provided.
 	MissingDescription,
 	/// A node id was not provided.