From d247a1b6ad686887f9bb393c8fd678908838bc3f Mon Sep 17 00:00:00 2001
From: UdjinM6 <UdjinM6@users.noreply.github.com>
Date: Mon, 23 Oct 2017 19:06:18 +0300
Subject: [PATCH 1/2] fix edge case for IS (skip inputs that are too large)

---
 src/wallet/wallet.cpp | 23 +++++++++++++++--------
 src/wallet/wallet.h   |  2 +-
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 5d2f27e072d0..5ce4c0781a43 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2421,7 +2421,7 @@ void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed, const
 }
 
 static void ApproximateBestSubset(vector<pair<CAmount, pair<const CWalletTx*,unsigned int> > >vValue, const CAmount& nTotalLower, const CAmount& nTargetValue,
-                                  vector<char>& vfBest, CAmount& nBest, int iterations = 1000)
+                                  vector<char>& vfBest, CAmount& nBest, int iterations = 1000, bool fUseInstantSend = false)
 {
     vector<char> vfIncluded;
 
@@ -2451,6 +2451,11 @@ static void ApproximateBestSubset(vector<pair<CAmount, pair<const CWalletTx*,uns
                     vfIncluded[i] = true;
                     if (nTotal >= nTargetValue)
                     {
+                        if (fUseInstantSend && nTotal > sporkManager.GetSporkValue(SPORK_5_INSTANTSEND_MAX_VALUE)) {
+                            nTotal -= vValue[i].first;
+                            vfIncluded[i] = false;
+                            continue;
+                        }
                         fReachedTarget = true;
                         if (nTotal < nBest)
                         {
@@ -2493,14 +2498,16 @@ bool less_then_denom (const COutput& out1, const COutput& out2)
 }
 
 bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int nConfTheirs, vector<COutput> vCoins,
-                                 set<pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet) const
+                                 set<pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet, bool fUseInstantSend) const
 {
     setCoinsRet.clear();
     nValueRet = 0;
 
     // List of values less than target
     pair<CAmount, pair<const CWalletTx*,unsigned int> > coinLowestLarger;
-    coinLowestLarger.first = std::numeric_limits<CAmount>::max();
+    coinLowestLarger.first = fUseInstantSend
+                                        ? sporkManager.GetSporkValue(SPORK_5_INSTANTSEND_MAX_VALUE)
+                                        : std::numeric_limits<CAmount>::max();
     coinLowestLarger.second.first = NULL;
     vector<pair<CAmount, pair<const CWalletTx*,unsigned int> > > vValue;
     CAmount nTotalLower = 0;
@@ -2586,9 +2593,9 @@ bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int
     vector<char> vfBest;
     CAmount nBest;
 
-    ApproximateBestSubset(vValue, nTotalLower, nTargetValue, vfBest, nBest);
+    ApproximateBestSubset(vValue, nTotalLower, nTargetValue, vfBest, nBest, fUseInstantSend);
     if (nBest != nTargetValue && nTotalLower >= nTargetValue + MIN_CHANGE)
-        ApproximateBestSubset(vValue, nTotalLower, nTargetValue + MIN_CHANGE, vfBest, nBest);
+        ApproximateBestSubset(vValue, nTotalLower, nTargetValue + MIN_CHANGE, vfBest, nBest, fUseInstantSend);
 
     // If we have a bigger coin and (either the stochastic approximation didn't find a good solution,
     //                                   or the next bigger coin is closer), return the bigger coin
@@ -2697,9 +2704,9 @@ bool CWallet::SelectCoins(const CAmount& nTargetValue, set<pair<const CWalletTx*
     }
 
     bool res = nTargetValue <= nValueFromPresetInputs ||
-        SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 6, vCoins, setCoinsRet, nValueRet) ||
-        SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 1, vCoins, setCoinsRet, nValueRet) ||
-        (bSpendZeroConfChange && SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1, vCoins, setCoinsRet, nValueRet));
+        SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 6, vCoins, setCoinsRet, nValueRet, fUseInstantSend) ||
+        SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 1, vCoins, setCoinsRet, nValueRet, fUseInstantSend) ||
+        (bSpendZeroConfChange && SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1, vCoins, setCoinsRet, nValueRet, fUseInstantSend));
 
     // because SelectCoinsMinConf clears the setCoinsRet, we now add the possible inputs to the coinset
     setCoinsRet.insert(setPresetCoins.begin(), setPresetCoins.end());
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 0671f7d3aabe..2e79cded1f9d 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -772,7 +772,7 @@ class CWallet : public CCryptoKeyStore, public CValidationInterface
      * completion the coin set and corresponding actual target value is
      * assembled
      */
-    bool SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int nConfTheirs, std::vector<COutput> vCoins, std::set<std::pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet) const;
+    bool SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int nConfTheirs, std::vector<COutput> vCoins, std::set<std::pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet, bool fUseInstantSend = false) const;
 
     bool SelectCoinsByDenominations(int nDenom, CAmount nValueMin, CAmount nValueMax, std::vector<CTxIn>& vecTxInRet, std::vector<COutput>& vCoinsRet, CAmount& nValueRet, int nPrivateSendRoundsMin, int nPrivateSendRoundsMax);
     bool GetCollateralTxIn(CTxIn& txinRet, CAmount& nValueRet) const;

From 57da68c8dbf3c6a68e2290ae4d1e6b13571f8644 Mon Sep 17 00:00:00 2001
From: UdjinM6 <UdjinM6@users.noreply.github.com>
Date: Tue, 24 Oct 2017 03:48:06 +0300
Subject: [PATCH 2/2] fix

---
 src/wallet/wallet.cpp | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 5ce4c0781a43..9fc76ac6c6b1 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2439,6 +2439,9 @@ static void ApproximateBestSubset(vector<pair<CAmount, pair<const CWalletTx*,uns
         {
             for (unsigned int i = 0; i < vValue.size(); i++)
             {
+                if (fUseInstantSend && nTotal + vValue[i].first > sporkManager.GetSporkValue(SPORK_5_INSTANTSEND_MAX_VALUE)) {
+                    continue;
+                }
                 //The solver here uses a randomized algorithm,
                 //the randomness serves no real security purpose but is just
                 //needed to prevent degenerate behavior and it is important
@@ -2451,11 +2454,6 @@ static void ApproximateBestSubset(vector<pair<CAmount, pair<const CWalletTx*,uns
                     vfIncluded[i] = true;
                     if (nTotal >= nTargetValue)
                     {
-                        if (fUseInstantSend && nTotal > sporkManager.GetSporkValue(SPORK_5_INSTANTSEND_MAX_VALUE)) {
-                            nTotal -= vValue[i].first;
-                            vfIncluded[i] = false;
-                            continue;
-                        }
                         fReachedTarget = true;
                         if (nTotal < nBest)
                         {