Explicitly filter out partial groups when we don't want them

Instead of hacking OutputGroup::m_ancestors to discourage the inclusion
of partial groups via the eligibility filter, add a parameter to the
eligibility filter that indicates whether we want to include the group.
Then for those partial groups, don't return them in GroupOutputs if we
indicate they aren't desired.

Author: achow101

src/wallet/coinselection.h

@@ -62,9 +62,11 @@ struct CoinEligibilityFilter
     const int conf_theirs;
     const uint64_t max_ancestors;
     const uint64_t max_descendants;
+    const bool m_include_partial_groups{false}; //! Include partial destination groups when avoid_reuse and there are full groups
 
     CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_ancestors) {}
     CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors, uint64_t max_descendants) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_descendants) {}
+    CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors, uint64_t max_descendants, bool include_partial) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_descendants), m_include_partial_groups(include_partial) {}
 };
 
 struct OutputGroup

src/wallet/wallet.cpp

@@ -2387,7 +2387,7 @@ bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, const CoinEligibil
             effective_feerate = coin_selection_params.effective_fee;
         }
 
-        std::vector<OutputGroup> groups = GroupOutputs(coins, !coin_selection_params.m_avoid_partial_spends, eligibility_filter.max_ancestors, effective_feerate, long_term_feerate, eligibility_filter, true /* positive_only */);
+        std::vector<OutputGroup> groups = GroupOutputs(coins, !coin_selection_params.m_avoid_partial_spends, effective_feerate, long_term_feerate, eligibility_filter, true /* positive_only */);
 
         // Calculate cost of change
         CAmount cost_of_change = GetDiscardRate(*this).GetFee(coin_selection_params.change_spend_size) + coin_selection_params.effective_fee.GetFee(coin_selection_params.change_output_size);
@@ -2397,7 +2397,7 @@ bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, const CoinEligibil
         bnb_used = true;
         return SelectCoinsBnB(groups, nTargetValue, cost_of_change, setCoinsRet, nValueRet, not_input_fees);
     } else {
-        std::vector<OutputGroup> groups = GroupOutputs(coins, !coin_selection_params.m_avoid_partial_spends, eligibility_filter.max_ancestors, CFeeRate(0), CFeeRate(0), eligibility_filter, false /* positive_only */);
+        std::vector<OutputGroup> groups = GroupOutputs(coins, !coin_selection_params.m_avoid_partial_spends, CFeeRate(0), CFeeRate(0), eligibility_filter, false /* positive_only */);
 
         bnb_used = false;
         return KnapsackSolver(nTargetValue, groups, setCoinsRet, nValueRet);
@@ -2489,8 +2489,8 @@ bool CWallet::SelectCoins(const std::vector<COutput>& vAvailableCoins, const CAm
         (m_spend_zero_conf_change && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, 2), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used)) ||
         (m_spend_zero_conf_change && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, std::min((size_t)4, max_ancestors/3), std::min((size_t)4, max_descendants/3)), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used)) ||
         (m_spend_zero_conf_change && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, max_ancestors/2, max_descendants/2), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used)) ||
-        (m_spend_zero_conf_change && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, max_ancestors-1, max_descendants-1), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used)) ||
-        (m_spend_zero_conf_change && !fRejectLongChains && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, std::numeric_limits<uint64_t>::max()), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+        (m_spend_zero_conf_change && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, max_ancestors-1, max_descendants-1, true /* include_partial_groups */), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used)) ||
+        (m_spend_zero_conf_change && !fRejectLongChains && SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, std::numeric_limits<uint64_t>::max(), std::numeric_limits<uint64_t>::max(), true /* include_partial_groups */), vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
 
     // because SelectCoinsMinConf clears the setCoinsRet, we now add the possible inputs to the coinset
     util::insert(setCoinsRet, setPresetCoins);
@@ -4193,7 +4193,7 @@ bool CWalletTx::IsImmatureCoinBase() const
     return GetBlocksToMaturity() > 0;
 }
 
-std::vector<OutputGroup> CWallet::GroupOutputs(const std::vector<COutput>& outputs, bool single_coin, const size_t max_ancestors, const CFeeRate& effective_feerate, const CFeeRate& long_term_feerate, const CoinEligibilityFilter& filter, bool positive_only) const {
+std::vector<OutputGroup> CWallet::GroupOutputs(const std::vector<COutput>& outputs, bool single_coin, const CFeeRate& effective_feerate, const CFeeRate& long_term_feerate, const CoinEligibilityFilter& filter, bool positive_only) const {
     std::vector<OutputGroup> groups;
     std::map<CTxDestination, OutputGroup> gmap;
     std::set<CTxDestination> full_groups;
@@ -4235,9 +4235,9 @@ std::vector<OutputGroup> CWallet::GroupOutputs(const std::vector<COutput>& outpu
     if (!single_coin) {
         for (auto& it : gmap) {
             auto& group = it.second;
-            if (full_groups.count(it.first) > 0) {
-                // Make this unattractive as we want coin selection to avoid it if possible
-                group.m_ancestors = max_ancestors - 1;
+            if (full_groups.count(it.first) > 0 && !filter.m_include_partial_groups) {
+                // Don't include partial groups if we don't want them
+                continue;
             }
             // If the OutputGroup is not eligible, don't add it
             if (positive_only && group.effective_value <= 0) continue;

src/wallet/wallet.h

@@ -841,7 +841,7 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
     bool IsSpentKey(const uint256& hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void SetSpentKeyState(WalletBatch& batch, const uint256& hash, unsigned int n, bool used, std::set<CTxDestination>& tx_destinations) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    std::vector<OutputGroup> GroupOutputs(const std::vector<COutput>& outputs, bool single_coin, const size_t max_ancestors, const CFeeRate& effective_feerate, const CFeeRate& long_term_feerate, const CoinEligibilityFilter& filter, bool positive_only) const;
+    std::vector<OutputGroup> GroupOutputs(const std::vector<COutput>& outputs, bool single_coin, const CFeeRate& effective_feerate, const CFeeRate& long_term_feerate, const CoinEligibilityFilter& filter, bool positive_only) const;
 
     bool IsLockedCoin(uint256 hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void LockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);