f! log_vec macro

Author: wpaulino

lightning/src/events/bump_transaction.rs

@@ -856,9 +856,8 @@ where
 			BumpTransactionEvent::HTLCResolution {
 				claim_id, target_feerate_sat_per_1000_weight, htlc_descriptors, tx_lock_time,
 			} => {
-				log_info!(self.logger, "Handling HTLC bump (claim_id = {}, htlcs_to_claim = {:?})",
-					log_bytes!(claim_id.0),
-					htlc_descriptors.iter().map(|d| d.outpoint().to_string()).collect::<Vec<_>>());
+				log_info!(self.logger, "Handling HTLC bump (claim_id = {}, htlcs_to_claim = {})",
+					log_bytes!(claim_id.0), log_vec!(htlc_descriptors.iter().map(|d| d.outpoint()).collect()));
 				if let Err(_) = self.handle_htlc_resolution(
 					*claim_id, *target_feerate_sat_per_1000_weight, htlc_descriptors, *tx_lock_time,
 				) {

lightning/src/util/logger.rs

@@ -169,6 +169,25 @@ impl<'a> core::fmt::Display for DebugBytes<'a> {
 	}
 }
 
+/// Wrapper for logging `Vec`s.
+///
+/// This is not exported to bindings users as fmt can't be used in C
+#[doc(hidden)]
+pub struct DebugVec<'a, T: core::fmt::Display>(pub &'a Vec<T>);
+impl<'a, T: core::fmt::Display> core::fmt::Display for DebugVec<'a, T> {
+	fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
+		write!(f, "[")?;
+		if let Some(item) = self.0.first() {
+			write!(f, "{}", item)?;
+		}
+		for i in self.0.iter().skip(1) {
+			write!(f, ", {}", i)?;
+		}
+		write!(f, "]")?;
+		Ok(())
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use crate::util::logger::{Logger, Level};

lightning/src/util/macro_logger.rs

@@ -17,6 +17,12 @@ use crate::routing::router::Route;
 use crate::ln::chan_utils::HTLCClaim;
 use crate::util::logger::DebugBytes;
 
+macro_rules! log_vec {
+	($obj: expr) => {
+		$crate::util::logger::DebugVec(&$obj)
+	}
+}
+
 /// Logs a pubkey in hex format.
 #[macro_export]
 macro_rules! log_pubkey {