Include prevtx weight in FundingTxContributions::InputsOnly

In preparation for having ChannelManager::splice_channel take
FundingTxContributions, add a weight to the
FundingTxContributions::InputsOnly, which supports the splice-in use
case.

Author: jkczyz

lightning/src/ln/channel.rs

@@ -6024,7 +6024,9 @@ impl FundingNegotiationContext {
 		};
 
 		let (inputs_to_contribute, change_script) = match self.funding_tx_contributions {
-			FundingTxContributions::InputsOnly { inputs, change_script } => (inputs, change_script),
+			FundingTxContributions::InputsOnly { inputs, change_script } => {
+				(inputs.into_iter().map(|(txin, tx, _)| (txin, tx)).collect(), change_script)
+			},
 		};
 
 		// Add change output if necessary
@@ -6078,7 +6080,7 @@ pub enum FundingTxContributions {
 	InputsOnly {
 		/// The inputs used to meet the contributed amount. Any excess amount will be sent to a
 		/// change output.
-		inputs: Vec<(TxIn, Transaction)>,
+		inputs: Vec<(TxIn, Transaction, Weight)>,
 
 		/// An optional change output script. This will be used if needed or, if not set, generated
 		/// using `SignerProvider::get_destination_script`.
@@ -6088,7 +6090,7 @@ pub enum FundingTxContributions {
 
 impl FundingTxContributions {
 	/// Returns an inputs to be contributed to the funding transaction.
-	pub fn inputs(&self) -> &[(TxIn, Transaction)] {
+	pub fn inputs(&self) -> &[(TxIn, Transaction, Weight)] {
 		match self {
 			FundingTxContributions::InputsOnly { inputs, .. } => &inputs[..],
 		}
@@ -10700,9 +10702,8 @@ where
 				err,
 			),
 		})?;
-		// Convert inputs
-		let mut funding_inputs = Vec::new();
-		for (txin, tx, _) in our_funding_inputs.into_iter() {
+
+		for (_, tx, _) in our_funding_inputs.iter() {
 			const MESSAGE_TEMPLATE: msgs::TxAddInput = msgs::TxAddInput {
 				channel_id: ChannelId([0; 32]),
 				serial_id: 0,
@@ -10717,12 +10718,10 @@ where
 					err: format!("Funding input's prevtx is too large for tx_add_input"),
 				});
 			}
-
-			funding_inputs.push((txin, tx));
 		}
 
 		let funding_tx_contributions =
-			FundingTxContributions::InputsOnly { inputs: funding_inputs, change_script };
+			FundingTxContributions::InputsOnly { inputs: our_funding_inputs, change_script };
 
 		let prev_funding_input = self.funding.to_splice_funding_input();
 		let funding_negotiation_context = FundingNegotiationContext {
@@ -12499,7 +12498,7 @@ where
 	pub fn new_outbound<ES: Deref, F: Deref, L: Deref>(
 		fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
 		counterparty_node_id: PublicKey, their_features: &InitFeatures, funding_satoshis: u64,
-		funding_inputs: Vec<(TxIn, Transaction)>, user_id: u128, config: &UserConfig,
+		funding_inputs: Vec<(TxIn, Transaction, Weight)>, user_id: u128, config: &UserConfig,
 		current_chain_height: u32, outbound_scid_alias: u64, funding_confirmation_target: ConfirmationTarget,
 		logger: L,
 	) -> Result<Self, APIError>
@@ -12660,7 +12659,7 @@ where
 	{
 		// TODO(dual_funding): Take these as input once supported
 		let (our_funding_contribution, our_funding_contribution_sats) = (SignedAmount::ZERO, 0u64);
-		let our_funding_inputs = Vec::new();
+		let our_funding_inputs: Vec<(TxIn, Transaction, Weight)> = Vec::new();
 
 		let channel_value_satoshis =
 			our_funding_contribution_sats.saturating_add(msg.common_fields.funding_satoshis);
@@ -12729,7 +12728,7 @@ 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: our_funding_inputs,
+				inputs_to_contribute: our_funding_inputs.into_iter().map(|(txin, tx, _)| (txin, tx)).collect(),
 				shared_funding_input: None,
 				shared_funding_output: SharedOwnedOutput::new(shared_funding_output, our_funding_contribution_sats),
 				outputs_to_contribute: Vec::new(),

lightning/src/ln/dual_funding_tests.rs

@@ -48,10 +48,7 @@ fn do_test_v2_channel_establishment(session: V2ChannelEstablishmentTestSession)
 	let initiator_funding_inputs: Vec<_> = create_dual_funding_utxos_with_prev_txs(
 		&nodes[0],
 		&[session.initiator_input_value_satoshis],
-	)
-	.into_iter()
-	.map(|(txin, tx, _)| (txin, tx))
-	.collect();
+	);
 
 	// Alice creates a dual-funded channel as initiator.
 	let funding_satoshis = session.funding_input_sats;

lightning/src/ln/interactivetxs.rs

@@ -1884,7 +1884,7 @@ pub(super) fn calculate_change_output_value(
 
 	let mut total_input_satoshis = 0u64;
 	let mut our_funding_inputs_weight = 0u64;
-	for (txin, tx) in context.funding_tx_contributions.inputs().iter() {
+	for (txin, tx, _) in context.funding_tx_contributions.inputs().iter() {
 		let txid = tx.compute_txid();
 		if txin.previous_output.txid != txid {
 			return Err(AbortReason::PrevTxOutInvalid);
@@ -1894,6 +1894,7 @@ pub(super) fn calculate_change_output_value(
 			.get(txin.previous_output.vout as usize)
 			.ok_or(AbortReason::PrevTxOutInvalid)?;
 		total_input_satoshis = total_input_satoshis.saturating_add(output.value.to_sat());
+		// FIXME: Can we use the Weight from context.funding_tx_contributions.inputs()?
 		let weight = estimate_input_weight(output).to_wu();
 		our_funding_inputs_weight = our_funding_inputs_weight.saturating_add(weight);
 	}
@@ -1958,7 +1959,7 @@ mod tests {
 	use bitcoin::transaction::Version;
 	use bitcoin::{
 		OutPoint, PubkeyHash, ScriptBuf, Sequence, SignedAmount, Transaction, TxIn, TxOut,
-		WPubkeyHash, Witness,
+		WPubkeyHash, Weight, Witness,
 	};
 	use core::ops::Deref;
 
@@ -2969,9 +2970,10 @@ mod tests {
 					sequence: Sequence::ZERO,
 					witness: Witness::new(),
 				};
-				(txin, tx)
+				let weight = Weight::ZERO;
+				(txin, tx, weight)
 			})
-			.collect::<Vec<(TxIn, Transaction)>>();
+			.collect::<Vec<(TxIn, Transaction, Weight)>>();
 		let funding_tx_contributions =
 			FundingTxContributions::InputsOnly { inputs, change_script: None };
 		let our_contributed = 110_000;