Second dust check on change output (after subtracting fee)

Author: optout21

lightning/src/ln/channel.rs

@@ -2091,9 +2091,12 @@ impl<SP: Deref> PendingV2Channel<SP> where SP::Target: SignerProvider {
 			};
 			let change_output_weight = get_output_weight(&change_output.script_pubkey).to_wu();
 			let change_output_fee = fee_for_weight(self.dual_funding_context.funding_feerate_sat_per_1000_weight, change_output_weight);
-			change_output.value = Amount::from_sat(change_value.saturating_sub(change_output_fee));
-			// Note: dust check not done here, should be handled before
-			funding_outputs.push(OutputOwned::Single(change_output));
+			let change_value_decreased_with_fee = change_value.saturating_sub(change_output_fee);
+			// Check dust limit again
+			if change_value_decreased_with_fee > self.context.holder_dust_limit_satoshis {
+				change_output.value = Amount::from_sat(change_value_decreased_with_fee);
+				funding_outputs.push(OutputOwned::Single(change_output));
+			}
 		}
 
 		let constructor_args = InteractiveTxConstructorArgs {