diff --git a/qa/rpc-tests/fundrawtransaction.py b/qa/rpc-tests/fundrawtransaction.py index 82e148c55a..b97e9aecdf 100755 --- a/qa/rpc-tests/fundrawtransaction.py +++ b/qa/rpc-tests/fundrawtransaction.py @@ -660,5 +660,75 @@ class RawTransactionsTest(BitcoinTestFramework): assert_fee_amount(result2['fee'], count_bytes(result2['hex']), 2 * result_fee_rate) assert_fee_amount(result3['fee'], count_bytes(result3['hex']), 10 * result_fee_rate) + ###################################### + # Test subtractFeeFromOutputs option # + ###################################### + + # Make sure there is exactly one input so coin selection can't skew the result + assert_equal(len(self.nodes[3].listunspent(1)), 1) + + inputs = [] + outputs = {self.nodes[2].getnewaddress(): 1} + rawtx = self.nodes[3].createrawtransaction(inputs, outputs) + + result = [self.nodes[3].fundrawtransaction(rawtx), # uses min_relay_tx_fee (set by settxfee) + self.nodes[3].fundrawtransaction(rawtx, {"subtractFeeFromOutputs": []}), # empty subtraction list + self.nodes[3].fundrawtransaction(rawtx, {"subtractFeeFromOutputs": [0]}), # uses min_relay_tx_fee (set by settxfee) + self.nodes[3].fundrawtransaction(rawtx, {"feeRate": 2*min_relay_tx_fee}), + self.nodes[3].fundrawtransaction(rawtx, {"feeRate": 2*min_relay_tx_fee, "subtractFeeFromOutputs": [0]})] + + dec_tx = [self.nodes[3].decoderawtransaction(tx['hex']) for tx in result] + output = [d['vout'][1 - r['changepos']]['value'] for d, r in zip(dec_tx, result)] + change = [d['vout'][r['changepos']]['value'] for d, r in zip(dec_tx, result)] + + assert_equal(result[0]['fee'], result[1]['fee'], result[2]['fee']) + assert_equal(result[3]['fee'], result[4]['fee']) + assert_equal(change[0], change[1]) + assert_equal(output[0], output[1]) + assert_equal(output[0], output[2] + result[2]['fee']) + assert_equal(change[0] + result[0]['fee'], change[2]) + assert_equal(output[3], output[4] + result[4]['fee']) + assert_equal(change[3] + result[3]['fee'], change[4]) + + inputs = [] + outputs = {self.nodes[2].getnewaddress(): value for value in (1.0, 1.1, 1.2, 1.3)} + keys = list(outputs.keys()) + rawtx = self.nodes[3].createrawtransaction(inputs, outputs) + + result = [self.nodes[3].fundrawtransaction(rawtx), + # split the fee between outputs 0, 2, and 3, but not output 1 + self.nodes[3].fundrawtransaction(rawtx, {"subtractFeeFromOutputs": [0, 2, 3]})] + + dec_tx = [self.nodes[3].decoderawtransaction(result[0]['hex']), + self.nodes[3].decoderawtransaction(result[1]['hex'])] + + # Nested list of non-change output amounts for each transaction + output = [[out['value'] for i, out in enumerate(d['vout']) if i != r['changepos']] + for d, r in zip(dec_tx, result)] + + # List of differences in output amounts between normal and subtractFee transactions + share = [o0 - o1 for o0, o1 in zip(output[0], output[1])] + + # output 1 is the same in both transactions + assert_equal(share[1], 0) + + # the other 3 outputs are smaller as a result of subtractFeeFromOutputs + assert_greater_than(share[0], 0) + assert_greater_than(share[2], 0) + assert_greater_than(share[3], 0) + + # outputs 2 and 3 take the same share of the fee + assert_equal(share[2], share[3]) + + # output 0 takes at least as much share of the fee, and no more than 2 satoshis more, than outputs 2 and 3 + assert_greater_than_or_equal(share[0], share[2]) + assert_greater_than_or_equal(share[2] + Decimal(2e-8), share[0]) + + # the fee is the same in both transactions + assert_equal(result[0]['fee'], result[1]['fee']) + + # the total subtracted from the outputs is equal to the fee + assert_equal(share[0] + share[2] + share[3], result[0]['fee']) + if __name__ == '__main__': RawTransactionsTest().main() diff --git a/qa/rpc-tests/test_framework/util.py b/qa/rpc-tests/test_framework/util.py index c29033595d..aca82c8b6f 100644 --- a/qa/rpc-tests/test_framework/util.py +++ b/qa/rpc-tests/test_framework/util.py @@ -524,14 +524,18 @@ def assert_fee_amount(fee, tx_size, fee_per_kB): if fee > (tx_size + 2) * fee_per_kB / 1000: raise AssertionError("Fee of %s BTC too high! (Should be %s BTC)"%(str(fee), str(target_fee))) -def assert_equal(thing1, thing2): - if thing1 != thing2: - raise AssertionError("%s != %s"%(str(thing1),str(thing2))) +def assert_equal(thing1, thing2, *args): + if thing1 != thing2 or any(thing1 != arg for arg in args): + raise AssertionError("not(%s)" % " == ".join(str(arg) for arg in (thing1, thing2) + args)) def assert_greater_than(thing1, thing2): if thing1 <= thing2: raise AssertionError("%s <= %s"%(str(thing1),str(thing2))) +def assert_greater_than_or_equal(thing1, thing2): + if thing1 < thing2: + raise AssertionError("%s < %s"%(str(thing1),str(thing2))) + def assert_raises(exc, fun, *args, **kwds): assert_raises_message(exc, None, fun, *args, **kwds) diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp index 82f8990562..2428ef04e2 100644 --- a/src/wallet/rpcwallet.cpp +++ b/src/wallet/rpcwallet.cpp @@ -2479,7 +2479,8 @@ UniValue fundrawtransaction(const JSONRPCRequest& request) throw runtime_error( "fundrawtransaction \"hexstring\" ( options )\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" + "This will not modify existing inputs, and will add at most one change output to the outputs.\n" + "No existing outputs will be modified unless \"subtractFeeFromOutputs\" is specified.\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" @@ -2491,11 +2492,17 @@ UniValue fundrawtransaction(const JSONRPCRequest& request) "1. \"hexstring\" (string, required) The hex string of the raw transaction\n" "2. options (object, optional)\n" " {\n" - " \"changeAddress\" (string, optional, default pool address) The bitcoin address to receive the change\n" - " \"changePosition\" (numeric, optional, default random) The index of the change output\n" - " \"includeWatching\" (boolean, optional, default false) Also select inputs which are watch only\n" - " \"lockUnspents\" (boolean, optional, default false) Lock selected unspent outputs\n" - " \"feeRate\" (numeric, optional, default not set: makes wallet determine the fee) Set a specific feerate (" + CURRENCY_UNIT + " per KB)\n" + " \"changeAddress\" (string, optional, default pool address) The bitcoin address to receive the change\n" + " \"changePosition\" (numeric, optional, default random) The index of the change output\n" + " \"includeWatching\" (boolean, optional, default false) Also select inputs which are watch only\n" + " \"lockUnspents\" (boolean, optional, default false) Lock selected unspent outputs\n" + " \"feeRate\" (numeric, optional, default not set: makes wallet determine the fee) Set a specific feerate (" + CURRENCY_UNIT + " per KB)\n" + " \"subtractFeeFromOutputs\" (array, optional) A json array of integers.\n" + " The fee will be equally deducted from the amount of each specified output.\n" + " The outputs are specified by their zero-based index, before any change output is added.\n" + " Those recipients will receive less bitcoins than you enter in their corresponding amount field.\n" + " If no outputs are specified here, the sender pays the fee.\n" + " [vout_index,...]\n" " }\n" " for backward compatibility: passing in a true instead of an object will result in {\"includeWatching\":true}\n" "\nResult:\n" @@ -2523,6 +2530,8 @@ UniValue fundrawtransaction(const JSONRPCRequest& request) bool lockUnspents = false; CFeeRate feeRate = CFeeRate(0); bool overrideEstimatedFeerate = false; + UniValue subtractFeeFromOutputs; + set setSubtractFeeFromOutputs; if (request.params.size() > 1) { if (request.params[1].type() == UniValue::VBOOL) { @@ -2541,6 +2550,7 @@ UniValue fundrawtransaction(const JSONRPCRequest& request) {"includeWatching", UniValueType(UniValue::VBOOL)}, {"lockUnspents", UniValueType(UniValue::VBOOL)}, {"feeRate", UniValueType()}, // will be checked below + {"subtractFeeFromOutputs", UniValueType(UniValue::VARR)}, }, true, true); @@ -2567,6 +2577,9 @@ UniValue fundrawtransaction(const JSONRPCRequest& request) feeRate = CFeeRate(AmountFromValue(options["feeRate"])); overrideEstimatedFeerate = true; } + + if (options.exists("subtractFeeFromOutputs")) + subtractFeeFromOutputs = options["subtractFeeFromOutputs"].get_array(); } } @@ -2581,10 +2594,21 @@ UniValue fundrawtransaction(const JSONRPCRequest& request) if (changePosition != -1 && (changePosition < 0 || (unsigned int)changePosition > tx.vout.size())) throw JSONRPCError(RPC_INVALID_PARAMETER, "changePosition out of bounds"); + for (unsigned int idx = 0; idx < subtractFeeFromOutputs.size(); idx++) { + int pos = subtractFeeFromOutputs[idx].get_int(); + if (setSubtractFeeFromOutputs.count(pos)) + throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid parameter, duplicated position: %d", pos)); + if (pos < 0) + throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid parameter, negative position: %d", pos)); + if (pos >= int(tx.vout.size())) + throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid parameter, position too large: %d", pos)); + setSubtractFeeFromOutputs.insert(pos); + } + CAmount nFeeOut; string strFailReason; - if(!pwalletMain->FundTransaction(tx, nFeeOut, overrideEstimatedFeerate, feeRate, changePosition, strFailReason, includeWatching, lockUnspents, changeAddress)) + if(!pwalletMain->FundTransaction(tx, nFeeOut, overrideEstimatedFeerate, feeRate, changePosition, strFailReason, includeWatching, lockUnspents, setSubtractFeeFromOutputs, changeAddress)) throw JSONRPCError(RPC_INTERNAL_ERROR, strFailReason); UniValue result(UniValue::VOBJ); diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp index 86816a62e2..ccda4a7c7f 100644 --- a/src/wallet/wallet.cpp +++ b/src/wallet/wallet.cpp @@ -2192,14 +2192,15 @@ bool CWallet::SelectCoins(const vector& vAvailableCoins, const CAmount& return res; } -bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool overrideEstimatedFeeRate, const CFeeRate& specificFeeRate, int& nChangePosInOut, std::string& strFailReason, bool includeWatching, bool lockUnspents, const CTxDestination& destChange) +bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool overrideEstimatedFeeRate, const CFeeRate& specificFeeRate, int& nChangePosInOut, std::string& strFailReason, bool includeWatching, bool lockUnspents, const std::set& setSubtractFeeFromOutputs, const CTxDestination& destChange) { vector vecSend; // Turn the txout set into a CRecipient vector - BOOST_FOREACH(const CTxOut& txOut, tx.vout) + for (size_t idx = 0; idx < tx.vout.size(); idx++) { - CRecipient recipient = {txOut.scriptPubKey, txOut.nValue, false}; + const CTxOut& txOut = tx.vout[idx]; + CRecipient recipient = {txOut.scriptPubKey, txOut.nValue, setSubtractFeeFromOutputs.count(idx) == 1}; vecSend.push_back(recipient); } @@ -2221,6 +2222,10 @@ bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool ov if (nChangePosInOut != -1) tx.vout.insert(tx.vout.begin() + nChangePosInOut, wtx.tx->vout[nChangePosInOut]); + // Copy output sizes from new transaction; they may have had the fee subtracted from them + for (unsigned int idx = 0; idx < tx.vout.size(); idx++) + tx.vout[idx].nValue = wtx.tx->vout[idx].nValue; + // Add new txins (keeping original txin scriptSig/order) BOOST_FOREACH(const CTxIn& txin, wtx.tx->vin) { diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h index b9fa6bb24b..92ad098486 100644 --- a/src/wallet/wallet.h +++ b/src/wallet/wallet.h @@ -780,7 +780,7 @@ public: * Insert additional inputs into the transaction by * calling CreateTransaction(); */ - bool FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool overrideEstimatedFeeRate, const CFeeRate& specificFeeRate, int& nChangePosInOut, std::string& strFailReason, bool includeWatching, bool lockUnspents, const CTxDestination& destChange = CNoDestination()); + bool FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool overrideEstimatedFeeRate, const CFeeRate& specificFeeRate, int& nChangePosInOut, std::string& strFailReason, bool includeWatching, bool lockUnspents, const std::set& setSubtractFeeFromOutputs, const CTxDestination& destChange = CNoDestination()); /** * Create a new transaction paying the recipients with a set of coins