Adjust balance check, cleanup (review)

lightning/src/ln/channel.rs

@@ -1183,12 +1183,6 @@ impl UnfundedChannelContext {
 #[derive(Clone)]
 pub(crate) struct PendingSpliceInfoPre {
 	pub our_funding_contribution: i64,
-	// TODO(splicing): Enable below fields
-	// pub funding_feerate_perkw: u32,
-	// pub locktime: u32,
-	// /// The funding inputs we will be contributing to the splice.
-	// /// TODO(splice): will be changed to TransactionU16LenLimited
-	// pub our_funding_inputs: Vec<(TxIn, Transaction)>,
 }
 
 #[cfg(splicing)]
@@ -3424,23 +3418,24 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		(context.holder_selected_channel_reserve_satoshis, context.counterparty_selected_channel_reserve_satoshis)
 	}
 
-	/// Check that a proposed channel value meets the channel reserve requirements or violates them (below reserve)
+	/// Check that a balance value meets the channel reserve requirements or violates them (below reserve).
+	/// The channel value is an input, so that this can be used for checks with new planned channel value.
 	#[cfg(any(dual_funding, splicing))]
-	pub fn check_channel_value_meets_reserve_requirements(&self, proposed_channel_value: u64) -> Result<(), ChannelError> {
+	pub fn check_balance_meets_reserve_requirements(&self, channel_value: u64, balance: u64) -> Result<(), ChannelError> {
 		let holder_selected_channel_reserve_satoshis = get_v2_channel_reserve_satoshis(
-			proposed_channel_value, self.holder_dust_limit_satoshis);
-		if proposed_channel_value < holder_selected_channel_reserve_satoshis {
+			channel_value, self.holder_dust_limit_satoshis);
+		if balance < holder_selected_channel_reserve_satoshis {
 			return Err(ChannelError::Warn(format!(
-				"Proposed channel value below reserve mandated by holder, {} vs {}",
-				proposed_channel_value, holder_selected_channel_reserve_satoshis,
+				"Balance below reserve mandated by holder, {} vs {}",
+				balance, holder_selected_channel_reserve_satoshis,
 			)));
 		}
 		let counterparty_selected_channel_reserve_satoshis = get_v2_channel_reserve_satoshis(
-			proposed_channel_value, self.counterparty_dust_limit_satoshis);
-		if proposed_channel_value < counterparty_selected_channel_reserve_satoshis {
+			channel_value, self.counterparty_dust_limit_satoshis);
+		if balance < counterparty_selected_channel_reserve_satoshis {
 			return Err(ChannelError::Warn(format!(
-				"Proposed channel value below reserve mandated by counterparty, {} vs {}",
-				proposed_channel_value, counterparty_selected_channel_reserve_satoshis,
+				"Balance below reserve mandated by counterparty, {} vs {}",
+				balance, counterparty_selected_channel_reserve_satoshis,
 			)));
 		}
 		Ok(())
@@ -3832,18 +3827,6 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		Ok(())
 	}
 
-	// /// Splice process starting; update state; update capacity, state, reset funding tx
-	// #[cfg(splicing)]
-	// pub(crate) fn splice_start<L: Deref>(&mut self, is_outgoing: bool, logger: &L) where L::Target: Logger {
-	// 	// Set state, by this point handshake is complete
-	// 	self.channel_state = ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT);
-
-	// 	log_info!(logger,
-	// 		"Splicing process started, new channel value {}, outgoing {}, channel_id {}",
-	// 		self.channel_value_satoshis, is_outgoing, self.channel_id,
-	// 	);
-	// }
-
 	/// Get the splice message that can be sent during splice initiation.
 	#[cfg(splicing)]
 	pub fn get_splice_init(&self, our_funding_contribution_satoshis: i64,
@@ -7465,14 +7448,10 @@ impl<SP: Deref> Channel<SP> where
 		where ES::Target: EntropySource, L::Target: Logger
 	{
 		if !self.context.is_outbound() {
-			// TODO(splicing): Enable starting in the line below
-			// Apply start of splice change in the state
-			// self.context.splice_start(false, logger);
+			// TODO(splicing): Apply start of splice (splice_start)
 
 			let splice_ack_msg = self.context.get_splice_ack(our_funding_contribution_satoshis)?;
 			// TODO(splicing): start interactive funding negotiation
-			// let _msg = post_chan.begin_interactive_funding_tx_construction(signer_provider, entropy_source, holder_node_id)
-			// 	.map_err(|err| ChannelError::Warn(format!("Failed to start interactive transaction construction, {:?}", err)))?;
 			Ok(splice_ack_msg)
 		} else {
 			Err(ChannelError::Warn("Internal consistency error: splice_init on inbound channel".into()))

lightning/src/ln/channelmanager.rs

@@ -9054,8 +9054,9 @@ where
 
 					let post_channel_value = PendingSpliceInfoPre::compute_post_value(pre_channel_value, msg.funding_contribution_satoshis, our_funding_contribution);
 
-					// Check for reserve requirement, it will also be checked later at tx_complete
-					let _res = chan.context.check_channel_value_meets_reserve_requirements(post_channel_value)
+					// Early check for reserve requirement, assuming maximum balance of full channel value
+					// This will also be checked later at tx_complete
+					let _res = chan.context.check_balance_meets_reserve_requirements(post_channel_value, post_channel_value)
 						.map_err(|e| MsgHandleErrInternal::from_chan_no_close(e, msg.channel_id))?;
 
 					// Check if a splice has been initiated already.
@@ -9127,8 +9128,9 @@ where
 					let pre_channel_value = chan.context.get_value_satoshis();
 					let post_channel_value = PendingSpliceInfoPre::compute_post_value(pre_channel_value, pending_splice.our_funding_contribution, msg.funding_contribution_satoshis);
 
-					// Check for reserve requirement, it will also be checked later at tx_complete
-					let _res = chan.context.check_channel_value_meets_reserve_requirements(post_channel_value)
+					// Early check for reserve requirement, assuming maximum balance of full channel value
+					// This will also be checked later at tx_complete
+					let _res = chan.context.check_balance_meets_reserve_requirements(post_channel_value, post_channel_value)
 						.map_err(|e| MsgHandleErrInternal::from_chan_no_close(e, msg.channel_id))?;
 				} else {
 					return Err(MsgHandleErrInternal::send_err_msg_no_close("Channel is not funded, cannot splice".to_owned(), msg.channel_id));