Add cost_of_change to coin_select parameters

Author: csralvall

src/wallet/coin_selection.rs

@@ -42,6 +42,7 @@
 //!         fee_rate: FeeRate,
 //!         amount_needed: u64,
 //!         fee_amount: u64,
+//!         cost_of_change: Option<u64>,
 //!     ) -> Result<CoinSelectionResult, bdk::Error> {
 //!         let mut selected_amount = 0;
 //!         let mut additional_weight = 0;
@@ -237,6 +238,7 @@ pub trait CoinSelectionAlgorithm<D: Database>: std::fmt::Debug {
         fee_rate: FeeRate,
         amount_needed: u64,
         fee_amount: u64,
+        cost_of_change: Option<u64>,
     ) -> Result<CoinSelectionResult, Error>;
 }
 
@@ -256,6 +258,7 @@ impl<D: Database> CoinSelectionAlgorithm<D> for LargestFirstCoinSelection {
         fee_rate: FeeRate,
         amount_needed: u64,
         mut fee_amount: u64,
+        cost_of_change: Option<u64>,
     ) -> Result<CoinSelectionResult, Error> {
         log::debug!(
             "amount_needed = `{}`, fee_amount = `{}`, fee_rate = `{:?}`",
@@ -370,6 +373,7 @@ impl<D: Database> CoinSelectionAlgorithm<D> for BranchAndBoundCoinSelection {
         fee_rate: FeeRate,
         amount_needed: u64,
         fee_amount: u64,
+        cost_of_change: Option<u64>,
     ) -> Result<CoinSelectionResult, Error> {
         // Mapping every (UTXO, usize) to an output group
         let required_utxos: Vec<OutputGroup<'_>> = required_utxos
@@ -735,6 +739,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 250_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -756,6 +761,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 20_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -777,6 +783,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 20_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -799,6 +806,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 500_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
     }
@@ -817,6 +825,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1000.0),
                 250_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
     }
@@ -837,6 +846,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 250_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -858,6 +868,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 20_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -879,6 +890,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 299756,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -910,6 +922,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 150_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
 
@@ -932,6 +945,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 500_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
     }
@@ -950,6 +964,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1000.0),
                 250_000,
                 FEE_AMOUNT,
+                None,
             )
             .unwrap();
     }
@@ -967,6 +982,7 @@ mod test {
                 FeeRate::from_sat_per_vb(1.0),
                 99932, // first utxo's effective value
                 0,
+                None,
             )
             .unwrap();
 
@@ -994,6 +1010,7 @@ mod test {
                     FeeRate::from_sat_per_vb(0.0),
                     target_amount,
                     0,
+                    None,
                 )
                 .unwrap();
             assert_eq!(result.selected_amount(), target_amount);

src/wallet/mod.rs

@@ -751,6 +751,8 @@ where
             fee_rate,
             outgoing,
             fee_amount,
+            // REVIEW: Add cost_of_change to TxParams
+            None,
         )?;
         let mut fee_amount = coin_selection.fee_amount;