PR #2403 fixups

lightning/src/chain/chaininterface.rs

@@ -59,6 +59,11 @@ pub enum ConfirmationTarget {
 /// A trait which should be implemented to provide feerate information on a number of time
 /// horizons.
 ///
+/// If access to a local mempool is not feasible, feerate estimates should be fetched from a set of
+/// third-parties hosting them. Note that this enables them to affect the propagation of your
+/// pre-signed transactions at any time and therefore endangers the safety of channels funds. It
+/// should be considered carefully as a deployment.
+///
 /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
 /// called from inside the library in response to chain events, P2P events, or timer events).
 pub trait FeeEstimator {

lightning/src/chain/onchaintx.rs

@@ -633,11 +633,12 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
 						.compute_package_feerate(fee_estimator, conf_target, force_feerate_bump);
 					if let Some(input_amount_sat) = output.funding_amount {
 						let fee_sat = input_amount_sat - tx.output.iter().map(|output| output.value).sum::<u64>();
-						if compute_feerate_sat_per_1000_weight(fee_sat, tx.weight() as u64) >=
-							 package_target_feerate_sat_per_1000_weight
-						{
-							log_debug!(logger, "Commitment transaction {} already meets required feerate {} sat/kW",
-								tx.txid(), package_target_feerate_sat_per_1000_weight);
+						let commitment_tx_feerate_sat_per_1000_weight =
+							compute_feerate_sat_per_1000_weight(fee_sat, tx.weight() as u64);
+						if commitment_tx_feerate_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight {
+							log_debug!(logger, "Pre-signed {} already has feerate {} sat/kW above required {} sat/kW",
+								log_tx!(tx), commitment_tx_feerate_sat_per_1000_weight,
+								package_target_feerate_sat_per_1000_weight);
 							return Some((new_timer, 0, OnchainClaim::Tx(tx.clone())));
 						}
 					}

lightning/src/util/logger.rs

@@ -173,18 +173,15 @@ impl<'a> core::fmt::Display for DebugBytes<'a> {
 ///
 /// This is not exported to bindings users as fmt can't be used in C
 #[doc(hidden)]
-pub struct DebugIter<T: fmt::Display, I: core::iter::Iterator<Item = T> + Clone>(pub core::cell::RefCell<I>);
+pub struct DebugIter<T: fmt::Display, I: core::iter::Iterator<Item = T> + Clone>(pub I);
 impl<T: fmt::Display, I: core::iter::Iterator<Item = T> + Clone> fmt::Display for DebugIter<T, I> {
 	fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-		use core::ops::DerefMut;
 		write!(f, "[")?;
-		let iter_ref = self.0.clone();
-		let mut iter = iter_ref.borrow_mut();
-		for item in iter.deref_mut() {
+		let mut iter = self.0.clone();
+		if let Some(item) = iter.next() {
 			write!(f, "{}", item)?;
-			break;
 		}
-		for item in iter.deref_mut() {
+		while let Some(item) = iter.next() {
 			write!(f, ", {}", item)?;
 		}
 		write!(f, "]")?;

lightning/src/util/macro_logger.rs

@@ -19,7 +19,7 @@ use crate::util::logger::DebugBytes;
 
 macro_rules! log_iter {
 	($obj: expr) => {
-		$crate::util::logger::DebugIter(core::cell::RefCell::new($obj))
+		$crate::util::logger::DebugIter($obj)
 	}
 }