Implement watchonly support in fundrawtransaction

Some code and test cases stolen from
Bryan Bishop <bryan@ledgerx.com> (pull bitcoin#5524).

qa/rpc-tests/fundrawtransaction.py

@@ -13,14 +13,15 @@ class RawTransactionsTest(BitcoinTestFramework):
 
     def setup_chain(self):
         print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
+        initialize_chain_clean(self.options.tmpdir, 4)
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(3, self.options.tmpdir)
+        self.nodes = start_nodes(4, self.options.tmpdir)
 
         connect_nodes_bi(self.nodes,0,1)
         connect_nodes_bi(self.nodes,1,2)
         connect_nodes_bi(self.nodes,0,2)
+        connect_nodes_bi(self.nodes,0,3)
 
         self.is_network_split=False
         self.sync_all()
@@ -31,11 +32,20 @@ def run_test(self):
 
         self.nodes[2].generate(1)
         self.sync_all()
-        self.nodes[0].generate(101)
+        self.nodes[0].generate(121)
         self.sync_all()
+
+        watchonly_address = self.nodes[0].getnewaddress()
+        watchonly_pubkey = self.nodes[0].validateaddress(watchonly_address)["pubkey"]
+        watchonly_amount = 200
+        self.nodes[3].importpubkey(watchonly_pubkey, "", True)
+        watchonly_txid = self.nodes[0].sendtoaddress(watchonly_address, watchonly_amount)
+        self.nodes[0].sendtoaddress(self.nodes[3].getnewaddress(), watchonly_amount / 10);
+
         self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(),1.5);
         self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(),1.0);
         self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(),5.0);
+
         self.sync_all()
         self.nodes[0].generate(1)
         self.sync_all()
@@ -428,11 +438,12 @@ def run_test(self):
         stop_nodes(self.nodes)
         wait_bitcoinds()
 
-        self.nodes = start_nodes(3, self.options.tmpdir)
+        self.nodes = start_nodes(4, self.options.tmpdir)
 
         connect_nodes_bi(self.nodes,0,1)
         connect_nodes_bi(self.nodes,1,2)
         connect_nodes_bi(self.nodes,0,2)
+        connect_nodes_bi(self.nodes,0,3)
         self.is_network_split=False
         self.sync_all()
 
@@ -525,5 +536,45 @@ def run_test(self):
         assert_equal(oldBalance+Decimal('50.19000000'), self.nodes[0].getbalance()) #0.19+block reward
 
 
+        ##################################################
+        # test a fundrawtransaction using only watchonly #
+        ##################################################
+
+        inputs = []
+        outputs = {self.nodes[2].getnewaddress() : watchonly_amount / 2}
+        rawtx = self.nodes[3].createrawtransaction(inputs, outputs)
+
+        result = self.nodes[3].fundrawtransaction(rawtx, True)
+        res_dec = self.nodes[0].decoderawtransaction(result["hex"])
+        assert_equal(len(res_dec["vin"]), 1)
+        assert_equal(res_dec["vin"][0]["txid"], watchonly_txid)
+
+        assert_equal("fee" in result.keys(), True)
+        assert_greater_than(result["changepos"], -1)
+
+        ###############################################################
+        # test fundrawtransaction using the entirety of watched funds #
+        ###############################################################
+
+        inputs = []
+        outputs = {self.nodes[2].getnewaddress() : watchonly_amount}
+        rawtx = self.nodes[3].createrawtransaction(inputs, outputs)
+
+        result = self.nodes[3].fundrawtransaction(rawtx, True)
+        res_dec = self.nodes[0].decoderawtransaction(result["hex"])
+        assert_equal(len(res_dec["vin"]), 2)
+        assert(res_dec["vin"][0]["txid"] == watchonly_txid or res_dec["vin"][1]["txid"] == watchonly_txid)
+
+        assert_greater_than(result["fee"], 0)
+        assert_greater_than(result["changepos"], -1)
+        assert_equal(result["fee"] + res_dec["vout"][result["changepos"]]["value"], watchonly_amount / 10)
+
+        signedtx = self.nodes[3].signrawtransaction(result["hex"])
+        assert(not signedtx["complete"])
+        signedtx = self.nodes[0].signrawtransaction(signedtx["hex"])
+        assert(signedtx["complete"])
+        self.nodes[0].sendrawtransaction(signedtx["hex"])
+
+
 if __name__ == '__main__':
     RawTransactionsTest().main()

src/coincontrol.h

@@ -14,6 +14,8 @@ class CCoinControl
     CTxDestination destChange;
     //! If false, allows unselected inputs, but requires all selected inputs be used
     bool fAllowOtherInputs;
+    //! Includes watch only addresses which match the ISMINE_WATCH_PUBKEY criteria
+    bool fAllowWatchOnly;
 
     CCoinControl()
     {
@@ -24,6 +26,7 @@ class CCoinControl
     {
         destChange = CNoDestination();
         fAllowOtherInputs = false;
+        fAllowWatchOnly = false;
         setSelected.clear();
     }
 

src/wallet/rpcwallet.cpp

@@ -2367,15 +2367,20 @@ UniValue fundrawtransaction(const UniValue& params, bool fHelp)
     if (!EnsureWalletIsAvailable(fHelp))
         return NullUniValue;
 
-    if (fHelp || params.size() != 1)
+    if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
-                            "fundrawtransaction \"hexstring\"\n"
+                            "fundrawtransaction \"hexstring\" includeWatching\n"
                             "\nAdd inputs to a transaction until it has enough in value to meet its out value.\n"
                             "This will not modify existing inputs, and will add one change output to the outputs.\n"
                             "Note that inputs which were signed may need to be resigned after completion since in/outputs have been added.\n"
                             "The inputs added will not be signed, use signrawtransaction for that.\n"
+                            "Note that all existing inputs must have their previous output transaction be in the wallet.\n"
+                            "Note that all inputs selected must be of standard form and P2SH scripts must be"
+                            "in the wallet using importaddress or addmultisigaddress (to calculate fees).\n"
+                            "Only pay-to-pubkey, multisig, and P2SH versions thereof are currently supported for watch-only\n"
                             "\nArguments:\n"
-                            "1. \"hexstring\"    (string, required) The hex string of the raw transaction\n"
+                            "1. \"hexstring\"     (string, required) The hex string of the raw transaction\n"
+                            "2. includeWatching (boolean, optional, default false) Also select inputs which are watch only\n"
                             "\nResult:\n"
                             "{\n"
                             "  \"hex\":       \"value\", (string)  The resulting raw transaction (hex-encoded string)\n"
@@ -2394,18 +2399,22 @@ UniValue fundrawtransaction(const UniValue& params, bool fHelp)
                             + HelpExampleCli("sendrawtransaction", "\"signedtransactionhex\"")
                             );
 
-    RPCTypeCheck(params, boost::assign::list_of(UniValue::VSTR));
+    RPCTypeCheck(params, boost::assign::list_of(UniValue::VSTR)(UniValue::VBOOL));
 
     // parse hex string from parameter
     CTransaction origTx;
     if (!DecodeHexTx(origTx, params[0].get_str()))
         throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
 
+    bool includeWatching = false;
+    if (params.size() > 1)
+        includeWatching = true;
+
     CMutableTransaction tx(origTx);
     CAmount nFee;
     string strFailReason;
     int nChangePos = -1;
-    if(!pwalletMain->FundTransaction(tx, nFee, nChangePos, strFailReason))
+    if(!pwalletMain->FundTransaction(tx, nFee, nChangePos, strFailReason, includeWatching))
         throw JSONRPCError(RPC_INTERNAL_ERROR, strFailReason);
 
     UniValue result(UniValue::VOBJ);

src/wallet/wallet.cpp

@@ -1524,7 +1524,9 @@ void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed, const
                 if (!(IsSpent(wtxid, i)) && mine != ISMINE_NO &&
                     !IsLockedCoin((*it).first, i) && (pcoin->vout[i].nValue > 0 || fIncludeZeroValue) &&
                     (!coinControl || !coinControl->HasSelected() || coinControl->fAllowOtherInputs || coinControl->IsSelected((*it).first, i)))
-                        vCoins.push_back(COutput(pcoin, i, nDepth, (mine & ISMINE_SPENDABLE) != ISMINE_NO));
+                        vCoins.push_back(COutput(pcoin, i, nDepth,
+                                                 ((mine & ISMINE_SPENDABLE) != ISMINE_NO) ||
+                                                  (coinControl && coinControl->fAllowWatchOnly && (mine & ISMINE_WATCH_PUBKEY) != ISMINE_NO)));
             }
         }
     }
@@ -1740,7 +1742,7 @@ bool CWallet::SelectCoins(const CAmount& nTargetValue, set<pair<const CWalletTx*
     return res;
 }
 
-bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount &nFeeRet, int& nChangePosRet, std::string& strFailReason)
+bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount &nFeeRet, int& nChangePosRet, std::string& strFailReason, bool includeWatching)
 {
     vector<CRecipient> vecSend;
 
@@ -1753,6 +1755,7 @@ bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount &nFeeRet, int& nC
 
     CCoinControl coinControl;
     coinControl.fAllowOtherInputs = true;
+    coinControl.fAllowWatchOnly = includeWatching;
     BOOST_FOREACH(const CTxIn& txin, tx.vin)
         coinControl.Select(txin.prevout);
 

src/wallet/wallet.h

@@ -630,7 +630,7 @@ class CWallet : public CCryptoKeyStore, public CValidationInterface
     CAmount GetWatchOnlyBalance() const;
     CAmount GetUnconfirmedWatchOnlyBalance() const;
     CAmount GetImmatureWatchOnlyBalance() const;
-    bool FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nChangePosRet, std::string& strFailReason);
+    bool FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nChangePosRet, std::string& strFailReason, bool includeWatching);
     bool CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletTx& wtxNew, CReserveKey& reservekey, CAmount& nFeeRet, int& nChangePosRet,
                            std::string& strFailReason, const CCoinControl *coinControl = NULL, bool sign = true);
     bool CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey);