f: remove unnecessary branch

Author: tankyleo

lightning/src/ln/channel.rs

@@ -7319,30 +7319,19 @@ impl<SP: Deref> FundedChannel<SP> where
 		let dust_exposure_limiting_feerate = self.context.get_dust_exposure_limiting_feerate(&fee_estimator);
 		let htlc_stats = self.context.get_pending_htlc_stats(None, dust_exposure_limiting_feerate);
 		let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(dust_exposure_limiting_feerate);
-		let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-			(0, 0)
+		let on_counterparty_tx_dust_htlc_exposure_msat = htlc_stats.on_counterparty_tx_dust_exposure_msat;
+		// Note that the total dust exposure includes both the dust HTLCs and the excess mining fees of the counterparty commitment transaction
+		if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
+			log_info!(logger, "Cannot accept value that would put our total dust exposure at {} over the limit {} on counterparty commitment tx",
+				on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
+			return Err(("Exceeded our total dust exposure limit on counterparty commitment tx", 0x1000|7))
+		}
+		let htlc_success_dust_limit = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+			0
 		} else {
 			let dust_buffer_feerate = self.context.get_dust_buffer_feerate(None) as u64;
-			(dust_buffer_feerate * htlc_timeout_tx_weight(self.context.get_channel_type()) / 1000,
-				dust_buffer_feerate * htlc_success_tx_weight(self.context.get_channel_type()) / 1000)
+			dust_buffer_feerate * htlc_success_tx_weight(self.context.get_channel_type()) / 1000
 		};
-		let exposure_dust_limit_timeout_sats = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
-		if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
-			let on_counterparty_tx_dust_htlc_exposure_msat = htlc_stats.on_counterparty_tx_dust_exposure_msat;
-			if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
-				log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
-					on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
-				return Err(("Exceeded our dust exposure limit on counterparty commitment tx", 0x1000|7))
-			}
-		} else {
-			let on_counterparty_tx_dust_htlc_exposure_msat = htlc_stats.on_counterparty_tx_dust_exposure_msat;
-			if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
-				log_info!(logger, "Cannot accept value that would put our exposure to tx fee dust at {} over the limit {} on counterparty commitment tx",
-					on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
-				return Err(("Exceeded our tx fee dust exposure limit on counterparty commitment tx", 0x1000|7))
-			}
-		}
-
 		let exposure_dust_limit_success_sats = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
 		if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
 			let on_holder_tx_dust_htlc_exposure_msat = htlc_stats.on_holder_tx_dust_exposure_msat;

lightning/src/ln/functional_tests.rs

@@ -10460,7 +10460,7 @@ fn do_test_max_dust_htlc_exposure(dust_outbound_balance: bool, exposure_breach_e
 		} else {
 			// Outbound dust balance: 5200 sats
 			nodes[0].logger.assert_log("lightning::ln::channel",
-				format!("Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+				format!("Cannot accept value that would put our total dust exposure at {} over the limit {} on counterparty commitment tx",
 					dust_htlc_on_counterparty_tx_msat * dust_htlc_on_counterparty_tx + commitment_tx_cost + 4,
 					max_dust_htlc_exposure_msat), 1);
 		}
@@ -10709,7 +10709,7 @@ fn do_test_nondust_htlc_fees_dust_exposure_delta(features: ChannelTypeFeatures)
 	expect_pending_htlcs_forwardable!(nodes[1]);
 	expect_htlc_handling_failed_destinations!(nodes[1].node.get_and_clear_pending_events(), &[HTLCDestination::FailedPayment { payment_hash }]);
 	nodes[1].logger.assert_log("lightning::ln::channel",
-		format!("Cannot accept value that would put our exposure to tx fee dust at {} over the limit {} on counterparty commitment tx",
+		format!("Cannot accept value that would put our total dust exposure at {} over the limit {} on counterparty commitment tx",
 			expected_dust_exposure_msat, expected_dust_exposure_msat - 1), 1);
 	check_added_monitors!(nodes[1], 1);