Use FundingTxInput in InteractiveTxConstructorArgs

InteractiveTxConstructor::new converts inputs given in channel.rs to
InputOwned. Instead of converting FundingTxInput in channel.rs to the
type needed by that constructor, pass in FundingTxInput and have it
converted directly to InputOwned there. This saves one conversion and
Vec allocation. It also lets us use the satisfaction_weight in an
upcoming refactor.

Author: jkczyz

lightning/src/ln/channel.rs

@@ -6617,14 +6617,6 @@ impl FundingNegotiationContext {
 			}
 		}
 
-		let funding_inputs = self
-			.our_funding_inputs
-			.into_iter()
-			.map(|FundingTxInput { utxo, sequence, prevtx }| {
-				(TxIn { previous_output: utxo.outpoint, sequence, ..Default::default() }, prevtx)
-			})
-			.collect();
-
 		let constructor_args = InteractiveTxConstructorArgs {
 			entropy_source,
 			holder_node_id,
@@ -6633,7 +6625,7 @@ impl FundingNegotiationContext {
 			feerate_sat_per_kw: self.funding_feerate_sat_per_1000_weight,
 			is_initiator: self.is_initiator,
 			funding_tx_locktime: self.funding_tx_locktime,
-			inputs_to_contribute: funding_inputs,
+			inputs_to_contribute: self.our_funding_inputs,
 			shared_funding_input: self.shared_funding_input,
 			shared_funding_output: SharedOwnedOutput::new(
 				shared_funding_output,
@@ -13669,12 +13661,6 @@ where
 			value: Amount::from_sat(funding.get_value_satoshis()),
 			script_pubkey: funding.get_funding_redeemscript().to_p2wsh(),
 		};
-		let inputs_to_contribute = our_funding_inputs
-			.into_iter()
-			.map(|FundingTxInput { utxo, sequence, prevtx }| {
-				(TxIn { previous_output: utxo.outpoint, sequence, ..Default::default() }, prevtx)
-			})
-			.collect();
 
 		let interactive_tx_constructor = Some(InteractiveTxConstructor::new(
 			InteractiveTxConstructorArgs {
@@ -13685,7 +13671,7 @@ where
 				feerate_sat_per_kw: funding_negotiation_context.funding_feerate_sat_per_1000_weight,
 				funding_tx_locktime: funding_negotiation_context.funding_tx_locktime,
 				is_initiator: false,
-				inputs_to_contribute,
+				inputs_to_contribute: our_funding_inputs,
 				shared_funding_input: None,
 				shared_funding_output: SharedOwnedOutput::new(shared_funding_output, our_funding_contribution_sats),
 				outputs_to_contribute: funding_negotiation_context.our_funding_outputs.clone(),

lightning/src/ln/funding.rs

@@ -198,6 +198,11 @@ impl FundingTxInput {
 		FundingTxInput::new(prevtx, vout, witness_weight, Script::is_p2tr)
 	}
 
+	#[cfg(test)]
+	pub(crate) fn new_p2pkh(prevtx: Transaction, vout: u32) -> Result<Self, ()> {
+		FundingTxInput::new(prevtx, vout, Weight::ZERO, Script::is_p2pkh)
+	}
+
 	/// The sequence number to use in the [`TxIn`].
 	///
 	/// [`TxIn`]: bitcoin::TxIn

lightning/src/ln/interactivetxs.rs

@@ -1920,7 +1920,7 @@ where
 	pub feerate_sat_per_kw: u32,
 	pub is_initiator: bool,
 	pub funding_tx_locktime: AbsoluteLockTime,
-	pub inputs_to_contribute: Vec<(TxIn, Transaction)>,
+	pub inputs_to_contribute: Vec<FundingTxInput>,
 	pub shared_funding_input: Option<SharedOwnedInput>,
 	pub shared_funding_output: SharedOwnedOutput,
 	pub outputs_to_contribute: Vec<TxOut>,
@@ -1959,21 +1959,14 @@ impl InteractiveTxConstructor {
 			shared_funding_output.clone(),
 		);
 
-		// Check for the existence of prevouts'
-		for (txin, tx) in inputs_to_contribute.iter() {
-			let vout = txin.previous_output.vout as usize;
-			if tx.output.get(vout).is_none() {
-				return Err(AbortReason::PrevTxOutInvalid);
-			}
-		}
 		let mut inputs_to_contribute: Vec<(SerialId, InputOwned)> = inputs_to_contribute
 			.into_iter()
-			.map(|(txin, tx)| {
+			.map(|FundingTxInput { utxo, sequence, prevtx: prev_tx }| {
 				let serial_id = generate_holder_serial_id(entropy_source, is_initiator);
-				let vout = txin.previous_output.vout as usize;
-				let prev_output = tx.output.get(vout).unwrap().clone(); // checked above
+				let txin = TxIn { previous_output: utxo.outpoint, sequence, ..Default::default() };
+				let prev_output = utxo.output;
 				let input =
-					InputOwned::Single(SingleOwnedInput { input: txin, prev_tx: tx, prev_output });
+					InputOwned::Single(SingleOwnedInput { input: txin, prev_tx, prev_output });
 				(serial_id, input)
 			})
 			.collect();
@@ -2283,12 +2276,12 @@ mod tests {
 
 	struct TestSession {
 		description: &'static str,
-		inputs_a: Vec<(TxIn, Transaction)>,
+		inputs_a: Vec<FundingTxInput>,
 		a_shared_input: Option<(OutPoint, TxOut, u64)>,
 		/// The funding output, with the value contributed
 		shared_output_a: (TxOut, u64),
 		outputs_a: Vec<TxOut>,
-		inputs_b: Vec<(TxIn, Transaction)>,
+		inputs_b: Vec<FundingTxInput>,
 		b_shared_input: Option<(OutPoint, TxOut, u64)>,
 		/// The funding output, with the value contributed
 		shared_output_b: (TxOut, u64),
@@ -2558,20 +2551,18 @@ mod tests {
 		}
 	}
 
-	fn generate_inputs(outputs: &[TestOutput]) -> Vec<(TxIn, Transaction)> {
+	fn generate_inputs(outputs: &[TestOutput]) -> Vec<FundingTxInput> {
 		let tx = generate_tx(outputs);
-		let txid = tx.compute_txid();
-		tx.output
+		outputs
 			.iter()
 			.enumerate()
-			.map(|(idx, _)| {
-				let txin = TxIn {
-					previous_output: OutPoint { txid, vout: idx as u32 },
-					script_sig: Default::default(),
-					sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
-					witness: Default::default(),
-				};
-				(txin, tx.clone())
+			.map(|(idx, output)| {
+				match output {
+					TestOutput::P2WPKH(_) => FundingTxInput::new_p2wpkh(tx.clone(), idx as u32).unwrap(),
+					TestOutput::P2WSH(_) => FundingTxInput::new_p2wsh(tx.clone(), idx as u32, Weight::from_wu(42)).unwrap(),
+					TestOutput::P2TR(_) => FundingTxInput::new_p2tr_key_spend(tx.clone(), idx as u32).unwrap(),
+					TestOutput::P2PKH(_) => FundingTxInput::new_p2pkh(tx.clone(), idx as u32).unwrap(),
+				}
 			})
 			.collect()
 	}
@@ -2619,37 +2610,26 @@ mod tests {
 		(generate_txout(&TestOutput::P2WSH(value)), local_value)
 	}
 
-	fn generate_fixed_number_of_inputs(count: u16) -> Vec<(TxIn, Transaction)> {
+	fn generate_fixed_number_of_inputs(count: u16) -> Vec<FundingTxInput> {
 		// Generate transactions with a total `count` number of outputs such that no transaction has a
 		// serialized length greater than u16::MAX.
 		let max_outputs_per_prevtx = 1_500;
 		let mut remaining = count;
-		let mut inputs: Vec<(TxIn, Transaction)> = Vec::with_capacity(count as usize);
+		let mut inputs: Vec<FundingTxInput> = Vec::with_capacity(count as usize);
 
 		while remaining > 0 {
 			let tx_output_count = remaining.min(max_outputs_per_prevtx);
 			remaining -= tx_output_count;
 
+			let outputs = vec![TestOutput::P2WPKH(1_000_000); tx_output_count as usize];
+
 			// Use unique locktime for each tx so outpoints are different across transactions
-			let tx = generate_tx_with_locktime(
-				&vec![TestOutput::P2WPKH(1_000_000); tx_output_count as usize],
-				(1337 + remaining).into(),
-			);
-			let txid = tx.compute_txid();
+			let tx = generate_tx_with_locktime(&outputs, (1337 + remaining).into());
 
-			let mut temp: Vec<(TxIn, Transaction)> = tx
-				.output
+			let mut temp: Vec<FundingTxInput> = outputs
 				.iter()
 				.enumerate()
-				.map(|(idx, _)| {
-					let input = TxIn {
-						previous_output: OutPoint { txid, vout: idx as u32 },
-						script_sig: Default::default(),
-						sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
-						witness: Default::default(),
-					};
-					(input, tx.clone())
-				})
+				.map(|(idx, _)| FundingTxInput::new_p2wpkh(tx.clone(), idx as u32).unwrap())
 				.collect();
 
 			inputs.append(&mut temp);
@@ -2860,13 +2840,11 @@ mod tests {
 		});
 
 		let tx = generate_tx(&[TestOutput::P2WPKH(1_000_000)]);
-		let invalid_sequence_input = TxIn {
-			previous_output: OutPoint { txid: tx.compute_txid(), vout: 0 },
-			..Default::default()
-		};
+		let mut invalid_sequence_input = FundingTxInput::new_p2wpkh(tx.clone(), 0).unwrap();
+		invalid_sequence_input.set_sequence(Default::default());
 		do_test_interactive_tx_constructor(TestSession {
 			description: "Invalid input sequence from initiator",
-			inputs_a: vec![(invalid_sequence_input, tx.clone())],
+			inputs_a: vec![invalid_sequence_input],
 			a_shared_input: None,
 			shared_output_a: generate_funding_txout(1_000_000, 1_000_000),
 			outputs_a: vec![],
@@ -2876,14 +2854,10 @@ mod tests {
 			outputs_b: vec![],
 			expect_error: Some((AbortReason::IncorrectInputSequenceValue, ErrorCulprit::NodeA)),
 		});
-		let duplicate_input = TxIn {
-			previous_output: OutPoint { txid: tx.compute_txid(), vout: 0 },
-			sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
-			..Default::default()
-		};
+		let duplicate_input = FundingTxInput::new_p2wpkh(tx.clone(), 0).unwrap();
 		do_test_interactive_tx_constructor(TestSession {
 			description: "Duplicate prevout from initiator",
-			inputs_a: vec![(duplicate_input.clone(), tx.clone()), (duplicate_input, tx.clone())],
+			inputs_a: vec![duplicate_input.clone(), duplicate_input],
 			a_shared_input: None,
 			shared_output_a: generate_funding_txout(1_000_000, 1_000_000),
 			outputs_a: vec![],
@@ -2894,35 +2868,27 @@ mod tests {
 			expect_error: Some((AbortReason::PrevTxOutInvalid, ErrorCulprit::NodeB)),
 		});
 		// Non-initiator uses same prevout as initiator.
-		let duplicate_input = TxIn {
-			previous_output: OutPoint { txid: tx.compute_txid(), vout: 0 },
-			sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
-			..Default::default()
-		};
+		let duplicate_input = FundingTxInput::new_p2wpkh(tx.clone(), 0).unwrap();
 		do_test_interactive_tx_constructor(TestSession {
 			description: "Non-initiator uses same prevout as initiator",
-			inputs_a: vec![(duplicate_input.clone(), tx.clone())],
+			inputs_a: vec![duplicate_input.clone()],
 			a_shared_input: None,
 			shared_output_a: generate_funding_txout(1_000_000, 905_000),
 			outputs_a: vec![],
-			inputs_b: vec![(duplicate_input.clone(), tx.clone())],
+			inputs_b: vec![duplicate_input],
 			b_shared_input: None,
 			shared_output_b: generate_funding_txout(1_000_000, 95_000),
 			outputs_b: vec![],
 			expect_error: Some((AbortReason::PrevTxOutInvalid, ErrorCulprit::NodeA)),
 		});
-		let duplicate_input = TxIn {
-			previous_output: OutPoint { txid: tx.compute_txid(), vout: 0 },
-			sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
-			..Default::default()
-		};
+		let duplicate_input = FundingTxInput::new_p2wpkh(tx.clone(), 0).unwrap();
 		do_test_interactive_tx_constructor(TestSession {
 			description: "Non-initiator uses same prevout as initiator",
-			inputs_a: vec![(duplicate_input.clone(), tx.clone())],
+			inputs_a: vec![duplicate_input.clone()],
 			a_shared_input: None,
 			shared_output_a: generate_funding_txout(1_000_000, 1_000_000),
 			outputs_a: vec![],
-			inputs_b: vec![(duplicate_input.clone(), tx.clone())],
+			inputs_b: vec![duplicate_input],
 			b_shared_input: None,
 			shared_output_b: generate_funding_txout(1_000_000, 0),
 			outputs_b: vec![],