Check if max_weight is exceeded

src/coin_grinder.rs

@@ -64,7 +64,7 @@ fn build_lookahead<Utxo: WeightedUtxo>(lookahead: Vec<(Amount, &Utxo)>, availabl
 fn calc_effective_values<Utxo: WeightedUtxo>(weighted_utxos: &[Utxo], fee_rate: FeeRate) -> Vec<(Amount, &Utxo)> {
     weighted_utxos
         .iter()
-        // calculate effective_value and waste for each w_utxo.
+        // calculate effective_value for each w_utxo.
         .map(|wu| (wu.effective_value(fee_rate), wu))
         // remove utxos that either had an error in the effective_value calculation.
         .filter(|(eff_val, _)| eff_val.is_some())
@@ -124,6 +124,7 @@ pub fn select_coins<Utxo: WeightedUtxo>(
     weighted_utxos: &[Utxo],
 ) -> Option<std::vec::IntoIter<&Utxo>> {
     let mut w_utxos = calc_effective_values::<Utxo>(weighted_utxos, fee_rate);
+
     let available_value = w_utxos.clone().into_iter().map(|(ev, _)| ev).checked_sum()?;
 
     // descending sort by effective_value using weight as tie breaker.
@@ -152,7 +153,7 @@ pub fn select_coins<Utxo: WeightedUtxo>(
     let mut weight_sum: Weight = Weight::ZERO;
     let mut best_weight_sum: Weight = max_selection_weight;
 
-    let _tx_weight_exceeded = false;
+    let mut max_tx_weight_exceeded = false;
 
     let mut next_utxo_index = 0;
 
@@ -175,6 +176,9 @@ pub fn select_coins<Utxo: WeightedUtxo>(
         if amount_sum + lookahead[tail] < total_target {
             cut = true;
         } else if weight_sum > best_weight_sum {
+            if weight_sum > max_selection_weight {
+                max_tx_weight_exceeded = true;
+            }
             // check if a better solution could exist.  IE there exists a utxo with a better
             // weight along the current branch
             if w_utxos[tail].1.weight() <= min_tail_weight[tail] {
@@ -384,4 +388,23 @@ mod tests {
 
         assert_coin_select_params(&params, None);
     }
+
+    #[test]
+    fn max_weight_exceeded () {
+        let mut wu = Vec::new();
+        for i in 0..10 {
+            wu.push("1 BTC/272");
+            wu.push("2 BTC/272");
+        }
+
+        let params = ParamsStr {
+            target: "29.5 BTC",
+            change_target: "1000000 sats",
+            max_weight: "3000",
+            fee_rate: "5",
+            weighted_utxos: wu
+        };
+
+        assert_coin_select_params(&params, None);
+    }
 }