Return improved error message when trying to spend Coinbase coins (#1373).

Extra parameter added to AvailableCoins to include or exclude Coinbase coins.
SelectCoins, used for sending taddr->taddr, will exclude Coinbase coins.

Added qa rpc test and a runtime parameter -regtestprotectcoinbase to enforce
the coinbase->zaddr consensus rule in regtest mode.

src/chainparams.cpp

@@ -336,6 +336,11 @@ CChainParams &Params(CBaseChainParams::Network network) {
 void SelectParams(CBaseChainParams::Network network) {
     SelectBaseParams(network);
     pCurrentParams = &Params(network);
+
+    // Some python qa rpc tests need to enforce the coinbase consensus rule
+    if (network == CBaseChainParams::REGTEST && mapArgs.count("-regtestprotectcoinbase")) {
+        regTestParams.SetRegTestCoinbaseMustBeProtected();
+    }
 }
 
 bool SelectParamsFromCommandLine()

src/chainparams.h

@@ -83,6 +83,8 @@ public:
     std::string GetFoundersRewardAddressAtIndex(int i) const;
     /** #1398 to return a fixed founders reward script for miner_tests */
     bool fMinerTestModeForFoundersRewardScript = false;
+    /** Enforce coinbase consensus rule in regtest mode */
+    void SetRegTestCoinbaseMustBeProtected() { consensus.fCoinbaseMustBeProtected = true; }
 protected:
     CChainParams() {}
 

src/wallet/asyncrpcoperation_sendmany.cpp

@@ -715,7 +715,7 @@ bool AsyncRPCOperation_sendmany::find_utxos(bool fAcceptCoinbase=false) {
 
     LOCK2(cs_main, pwalletMain->cs_wallet);
 
-    pwalletMain->AvailableCoins(vecOutputs, false, NULL, true);
+    pwalletMain->AvailableCoins(vecOutputs, false, NULL, true, fAcceptCoinbase);
 
     BOOST_FOREACH(const COutput& out, vecOutputs) {
         if (out.nDepth < mindepth_) {

src/wallet/wallet.cpp

@@ -2050,7 +2050,7 @@ CAmount CWallet::GetImmatureWatchOnlyBalance() const
 /**
  * populate vCoins with vector of available COutputs.
  */
-void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed, const CCoinControl *coinControl, bool fIncludeZeroValue) const
+void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed, const CCoinControl *coinControl, bool fIncludeZeroValue, bool fIncludeCoinBase) const
 {
     vCoins.clear();
 
@@ -2067,6 +2067,9 @@ void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed, const
             if (fOnlyConfirmed && !pcoin->IsTrusted())
                 continue;
 
+            if (pcoin->IsCoinBase() && !fIncludeCoinBase)
+                continue;
+
             if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0)
                 continue;
 
@@ -2232,10 +2235,38 @@ bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int
     return true;
 }
 
-bool CWallet::SelectCoins(const CAmount& nTargetValue, set<pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet, const CCoinControl* coinControl) const
+bool CWallet::SelectCoins(const CAmount& nTargetValue, set<pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet,  bool& fOnlyCoinbaseCoinsRet, bool& fNeedCoinbaseCoinsRet, const CCoinControl* coinControl) const
 {
-    vector<COutput> vCoins;
-    AvailableCoins(vCoins, true, coinControl);
+    // Output parameter fOnlyCoinbaseCoinsRet is set to true when the only available coins are coinbase utxos.
+    vector<COutput> vCoinsNoCoinbase, vCoinsWithCoinbase;
+    AvailableCoins(vCoinsNoCoinbase, true, coinControl, false, false);
+    AvailableCoins(vCoinsWithCoinbase, true, coinControl, false, true);
+    fOnlyCoinbaseCoinsRet = vCoinsNoCoinbase.size() == 0 && vCoinsWithCoinbase.size() > 0;
+
+    // If coinbase utxos can only be sent to zaddrs, exclude any coinbase utxos from coin selection.
+    bool fProtectCoinbase = Params().GetConsensus().fCoinbaseMustBeProtected;
+    vector<COutput> vCoins = (fProtectCoinbase) ? vCoinsNoCoinbase : vCoinsWithCoinbase;
+
+    // Output parameter fNeedCoinbaseCoinsRet is set to true if coinbase utxos need to be spent to meet target amount
+    if (fProtectCoinbase && vCoinsWithCoinbase.size() > vCoinsNoCoinbase.size()) {
+        CAmount value = 0;
+        for (const COutput& out : vCoinsNoCoinbase) {
+            if (!out.fSpendable) {
+                continue;
+            }
+            value += out.tx->vout[out.i].nValue;
+        }
+        if (value <= nTargetValue) {
+            CAmount valueWithCoinbase = 0;
+            for (const COutput& out : vCoinsWithCoinbase) {
+                if (!out.fSpendable) {
+                    continue;
+                }
+                valueWithCoinbase += out.tx->vout[out.i].nValue;
+            }
+            fNeedCoinbaseCoinsRet = (valueWithCoinbase >= nTargetValue);
+        }
+    }
 
     // coin control -> return all selected outputs (we want all selected to go into the transaction for sure)
     if (coinControl && coinControl->HasSelected())
@@ -2355,9 +2386,17 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend,
                 // Choose coins to use
                 set<pair<const CWalletTx*,unsigned int> > setCoins;
                 CAmount nValueIn = 0;
-                if (!SelectCoins(nTotalValue, setCoins, nValueIn, coinControl))
+                bool fOnlyCoinbaseCoins = false;
+                bool fNeedCoinbaseCoins = false;
+                if (!SelectCoins(nTotalValue, setCoins, nValueIn, fOnlyCoinbaseCoins, fNeedCoinbaseCoins, coinControl))
                 {
-                    strFailReason = _("Insufficient funds");
+                    if (fOnlyCoinbaseCoins && Params().GetConsensus().fCoinbaseMustBeProtected) {
+                        strFailReason = _("Coinbase funds can only be sent to a zaddr");
+                    } else if (fNeedCoinbaseCoins) {
+                        strFailReason = _("Insufficient funds, coinbase funds can only be spent after they have been sent to a zaddr");
+                    } else {
+                        strFailReason = _("Insufficient funds");
+                    }
                     return false;
                 }
                 BOOST_FOREACH(PAIRTYPE(const CWalletTx*, unsigned int) pcoin, setCoins)

src/wallet/wallet.h

@@ -556,7 +556,7 @@ public:
 class CWallet : public CCryptoKeyStore, public CValidationInterface
 {
 private:
-    bool SelectCoins(const CAmount& nTargetValue, std::set<std::pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet, const CCoinControl *coinControl = NULL) const;
+    bool SelectCoins(const CAmount& nTargetValue, std::set<std::pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet, bool& fOnlyCoinbaseCoinsRet, bool& fNeedCoinbaseCoinsRet, const CCoinControl *coinControl = NULL) const;
 
     CWalletDB *pwalletdbEncryption;
 
@@ -689,7 +689,7 @@ public:
     //! check whether we are allowed to upgrade (or already support) to the named feature
     bool CanSupportFeature(enum WalletFeature wf) { AssertLockHeld(cs_wallet); return nWalletMaxVersion >= wf; }
 
-    void AvailableCoins(std::vector<COutput>& vCoins, bool fOnlyConfirmed=true, const CCoinControl *coinControl = NULL, bool fIncludeZeroValue=false) const;
+    void AvailableCoins(std::vector<COutput>& vCoins, bool fOnlyConfirmed=true, const CCoinControl *coinControl = NULL, bool fIncludeZeroValue=false, bool fIncludeCoinBase=true) 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) const;
 
     bool IsSpent(const uint256& hash, unsigned int n) const;