Merge pull request #4906

fc0f52d Added a test for the pruning of extraneous inputs after ApproximateBestSet (Murch)
af9510e Moved set reduction to the end of ApproximateBestSubset to reduce performance impact (Murch)
5c03483 Coinselection prunes extraneous inputs from ApproximateBestSubset (AlSzacrel)

src/wallet/test/wallet_tests.cpp

@@ -328,4 +328,22 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests)
     empty_wallet();
 }
 
+BOOST_AUTO_TEST_CASE(pruning_in_ApproximateBestSet)
+{
+    CoinSet setCoinsRet;
+    CAmount nValueRet;
+
+    LOCK(wallet.cs_wallet);
+
+    empty_wallet();
+    for (int i = 0; i < 12; i++) 
+    {
+        add_coin(10*CENT);
+    }
+    add_coin(100*CENT);
+    add_coin(100*CENT);
+    BOOST_CHECK(wallet.SelectCoinsMinConf(221*CENT, 1, 6, vCoins, setCoinsRet, nValueRet));
+    BOOST_CHECK_EQUAL(nValueRet, 230*CENT);
+}
+
 BOOST_AUTO_TEST_SUITE_END()

src/wallet/wallet.cpp

@@ -1632,6 +1632,16 @@ static void ApproximateBestSubset(vector<pair<CAmount, pair<const CWalletTx*,uns
             }
         }
     }
+
+    //Reduces the approximate best subset by removing any inputs that are smaller than the surplus of nTotal beyond nTargetValue. 
+    for (unsigned int i = 0; i < vValue.size(); i++)
+    {                        
+        if (vfBest[i] && (nBest - vValue[i].first) >= nTargetValue )
+        {
+            vfBest[i] = false;
+            nBest -= vValue[i].first;
+        }
+    }
 }
 
 bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int nConfTheirs, vector<COutput> vCoins,