wallet: add SelectionResult::Merge

src/wallet/coinselection.cpp

@@ -433,6 +433,16 @@ void SelectionResult::AddInput(const OutputGroup& group)
     m_use_effective = !group.m_subtract_fee_outputs;
 }
 
+void SelectionResult::Merge(const SelectionResult& other)
+{
+    m_target += other.m_target;
+    m_use_effective |= other.m_use_effective;
+    if (m_algo == SelectionAlgorithm::MANUAL) {
+        m_algo = other.m_algo;
+    }
+    util::insert(m_selected_inputs, other.m_selected_inputs);
+}
+
 const std::set<COutput>& SelectionResult::GetInputSet() const
 {
     return m_selected_inputs;

src/wallet/coinselection.h

@@ -281,17 +281,16 @@ struct SelectionResult
 private:
     /** Set of inputs selected by the algorithm to use in the transaction */
     std::set<COutput> m_selected_inputs;
+    /** The target the algorithm selected for. Equal to the recipient amount plus non-input fees */
+    CAmount m_target;
+    /** The algorithm used to produce this result */
+    SelectionAlgorithm m_algo;
     /** Whether the input values for calculations should be the effective value (true) or normal value (false) */
     bool m_use_effective{false};
     /** The computed waste */
     std::optional<CAmount> m_waste;
 
 public:
-    /** The target the algorithm selected for. Note that this may not be equal to the recipient amount as it can include non-input fees */
-    const CAmount m_target;
-    /** The algorithm used to produce this result */
-    const SelectionAlgorithm m_algo;
-
     explicit SelectionResult(const CAmount target, SelectionAlgorithm algo)
         : m_target(target), m_algo(algo) {}
 
@@ -308,12 +307,18 @@ public:
     void ComputeAndSetWaste(CAmount change_cost);
     [[nodiscard]] CAmount GetWaste() const;
 
+    void Merge(const SelectionResult& other);
+
     /** Get m_selected_inputs */
     const std::set<COutput>& GetInputSet() const;
     /** Get the vector of COutputs that will be used to fill in a CTransaction's vin */
     std::vector<COutput> GetShuffledInputVector() const;
 
     bool operator<(SelectionResult other) const;
+
+    CAmount GetTarget() const { return m_target; }
+
+    SelectionAlgorithm GetAlgo() const { return m_algo; }
 };
 
 std::optional<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_pool, const CAmount& selection_target, const CAmount& cost_of_change);

src/wallet/spend.cpp

@@ -667,7 +667,7 @@ std::optional<SelectionResult> SelectCoins(const CWallet& wallet, CoinsResult& a
 
     // Add preset inputs to result
     res->AddInput(preset_inputs);
-    if (res->m_algo == SelectionAlgorithm::MANUAL) {
+    if (res->GetAlgo() == SelectionAlgorithm::MANUAL) {
         res->ComputeAndSetWaste(coin_selection_params.m_cost_of_change);
     }
 
@@ -890,7 +890,7 @@ static util::Result<CreatedTransactionResult> CreateTransactionInternal(
     if (!result) {
         return util::Error{_("Insufficient funds")};
     }
-    TRACE5(coin_selection, selected_coins, wallet.GetName().c_str(), GetAlgorithmName(result->m_algo).c_str(), result->m_target, result->GetWaste(), result->GetSelectedValue());
+    TRACE5(coin_selection, selected_coins, wallet.GetName().c_str(), GetAlgorithmName(result->GetAlgo()).c_str(), result->GetTarget(), result->GetWaste(), result->GetSelectedValue());
 
     // Always make a change output
     // We will reduce the fee from this change output later, and remove the output if it is too small.